anatomy, abdomen Flashcards
(777 cards)
1
Q
What is a chryptorchism?
A
Undescended testicle - remove if can’t surgically descend or cancer.
2
Q
What peritoneum is associated with inguinal hernias - mostly in males?
A
Parietal
3
Q
Kidney malignancy Wilms tumor - which gene?
A
WT1
4
Q
When inferior poles of kidney fuse, what halts their ascent?
A
Inferior mesentery artery - “horseshoe kidney”
5
Q
If kidneys fail to develop, is the amniotic fluid level affected?
A
Yes, because of lack of urine. Oligohydramnios results
6
Q
Is hypoplastic lung related to oligohydramnios? If so, it is genetic?
A
Yes they are related, No, it is not genetic. Pulmonary hypoplasia is incomplete development of the lungs, resulting in an abnormally low number or size of bronchopulmonary segments or alveoli. A congenital malformation, it most often occurs secondary to other fetal abnormalities that interfere with normal development of the lungs. SEE that I have two different answers re if it is genetic.
Other source says: There may be a genetic component, but more commonly pulmonary hypoplasia is secondary to an underlying abnormality such as restrictive malformation of the chest wall and decreased fetal breathing (fetal neuromuscular disease), decreased fetal lung fluid (prolonged rupture of membrane, fetal renal dysplasias
7
Q
What’s an annular pancreas?
A
Ventral bud rotation gone astray, It should rotate dorsally and fuse with dorsal bud. An annular pancreas means it rotated ventrally, second part of the duodenum is surrounded by a ring of pancreatic tissue continuous with the head of the pancreas. This portion of the pancreas can constrict the duodenum and block or impair the flow of food to the rest of the intestines.
8
Q
What can failure of lateral folds in embryonic development result in?
A
Lateral folds are key to musculature in anterior abdominal wall - defects range from umbilical hernia (minor) to gastroschisis (major)
9
Q
What is gastroschisis?
A
An opening forms in the baby’s abdominal wall. The baby’s bowel pushes through this hole. The bowel then develops outside of the baby’s body in the amniotic fluid.
10
Q
In relation to the esophagus, how much does the proximal foregut rotate and what nerve is involved?
A
90 degrees counterclockwise. Vagus nerve.
11
Q
Half of baby’s diaphragm is rising higher - what happened?
A
Eventration. One muscular hemidiaphragm fails to develop - due to lack of muscle or phrenic nerve function/development. Due to pressure, abdominal organs are pushed into thorax - pleuroperitoneal folds contribute, as does development of septum transversum (becomes central tendon)
12
Q
Would esophageal atresia cause pneumonia?
A
No, it would end in a blind tube - and while associated with tracheoesophageal fistula, it does not open into the trachea, so pneumonia would not result.
13
Q
What does the tracheoeosophageal septem separate?
A
The ventral wall of the forgut (esophagus) from the laryngottracheal tube. - a fistula would result in fluid from esophagus into trachea and possible pneumonia.
14
Q
What does the septum transversum form?
A
The central tendon.
15
Q
What do the pleuroperitoneal folds form?
A
The posterolateral part of the diaphragm.
16
Q
What does the pleuropericarial fold form?
A
The fibrous pericardium.
17
Q
What do the cervical myotomes form?
A
Musculature of diaphragm.
18
Q
Malrotation of the midgut loop may result in what complication?
A
Midgut volvulus (without fixed mesentery).
19
Q
Absence of an ascending colon is caused by what?
A
Failure of cecal bud to descend.
20
Q
Does duplication of the intestine have a fixed mesentery?
A
Yes - no free movement.
21
Q
What is congenital megacolon due to?
A
Failure of migration of neural crest cells into wall of colon - lack of parasympathetic postganglionic neurons.
22
Q
What is Hirschsprung disease?
A
Congenital megacolon - neural crest migration problem.
23
Q
What is rectal atresia?
A
Failure to adequately recanalize - both anal and rectum exist - but are not connected.
24
Q
Incomplete separation of the cloaca would result in what?
A
Anal agenesis either with or without presence of a fistula.
25
What is the most common site of Meckel diverticulum?
Ileum. Outpouching is a persistence of vitelline duct and can be attached to the umbilicus.
26
Where is the most common site of ectopic pregnancy?
Uterine tubes -
27
Where is the most common site of implantation?
Fundus
28
What nerve carries general visceral afferent fibers from abdominal organs and can be involved in referred pain?
The greater splanchnic nerve.
29
Does the dorsal primary rami of intercostal nerves carry messages from abdominal organs?
Yes - pain from these fibers would be sharp and localized as opposed to dull and diffuse as occurs in referred pain.
30
Does the vagus nerve transmit pain?
No.
31
What nerve transmits pain from the pelvis?
The pelvic splanchinic nerve - parasympathetic, S2 to S4, contains visceral afferent fibers.
32
What is an indirect inguinal hermia?
When a loop of bowel enters the spermatic cord through the deep inguinal ring (lateral to the interior epigastric vessels).
33
Where does the ilioinguinal nerve run
with the spermatic cord to innervate the anterior portion of the scrotum and proximal parts of the genitals - and could be compressed during an indirect inguinal hernia
34
The iliohypogatric nerve - what does it innervate?
The skin of the suprapubic region.
35
What does the lateral femoral cutaneous nerve innervate?
The skin over the lateral thigh
36
What nerve innervates the band of skin superior to the iliac crest and inferior to the umbilicus?
subcostal
37
What innervates the musculature and skin of the perineum?
The pudendal.
38
What lymph drains direction from the stomach before draining into the cisterna chyli?
Celiac Lymph.
39
From where do the superior and inferior mesenteric lymph nodes receive drainage?
Below the stomach
40
Where do the lumbar lymph nodes receive drainage?
Structures inferior to the stomach.
41
What organ are the hepatic lymph nodes associated with
The liver
42
Where does the splenic artery run -
behind the stomach to the spleen from the celiac trunk.
43
During a laparoscopic cholecystectomy, a resident clamped the hepatoduodenal ligament instead of the cystic artery - which vessel would be occluded?
The proper hepatic artery. It lies near the foramen of Winslow. The common hepatic gives origin to the proper hepatic art. but does not run w/in the hepatoduodenal ligament.
44
What hernias of the intestines run through the deep inguinal ring?
Indirect.
45
Do direct intestinal hernias penetrate the deep inguinal ring?
No, they penetrate the abdominal wall medial to the inferior epigastric vessels through the inguinal triangle (of Hesselback)
46
Where do umbilical hernias exit?
The umbilicus
47
Where do femoral and lumbar hernias exit ?
femoral - through the fermoral ring inferior to the inguinal ligament; Lumbar can penetrate through superior (grynfeltt) or inferior (Petit) lumbar triangles
48
What type of germ cells does the pancreas come from?
Endoderm
49
start lippincott abdomen
BEGINS HERE
50
The kidneys are supplied by what arteries
Renal
51
What arteries supply the pyploric portion of the stomach?
Gastroduodenal artery.
52
The head of the pancreas is supplied by what arteries?
Superior and Inferior pancreaticoduodenal arteries.
53
The splenic flexure of the colon is supplied by what arteries?
Marginal - although I also have this answer: receives dual blood supply from the terminal branches of the superior mesenteric artery and the inferior mesenteric artery, thus making it prone to ischemic damage in cases of low blood pressure because it does not have its own primary source of blood.
54
Man lifting weights - what kind of hernia?
Direct - when comes through weakness in anterior abd wall. Borders are inferior epigastric artery localed laterally, semilunar line of rectus sheath medially, and inguinal ligament inferiorily.
55
A direct hernia exits from which ring?
Superficial inguinal ring - and does not usually descend into the scrotum - as do indirect hernias.
56
GI bleed - in lower left area - what artery?
Inferior mesenteric (I don't know if this is always right - but based on the xray-and this Q)
57
A remnant of the embryonic ventral mesentery is...?
the Falciform ligament.
58
Fractures on ribs 9 and 10 on left - what organ likely damaged?
Spleen, 1x3x5",7lbsR9r11 mneomonic
59
Meckel's diverticulitis - where will it be?
Lower ileum - a persistent remnant of embryonic vitelline duct (yolk sac). Mneumonic - rule of 2 (2" long, 2 ft proximal to ileoccecal valve, in 2% of the population
60
Woman with advanced polycystic kidney disease - what nerves convey visceral sensory fibers from renal capsule and cause referred pain to skin of suprapubic region?
Least splanchic - carries presynaptic symp. fibers from T12. Visceral afferent travel along refer pain to T12 dermatome. Further, the renal nerve plexus is supplied primarily from least splanchnic nerve - L1, L2.
61
Infant can't hold milk after 3 weeks of normal feeding - projectile vomit - nonbilous and nonbloody - what's best diagnosis?
Pyloric stenosis, prevents stomach contents from emptying into duodenum. usually present at 2 - 3 weeks after birth. Key is the vomit - nonbilous implies mlik not reach bile. nonbloody rules out possible GI bleed.
62
37 week old fetus, which fetal vessel is carrying the highest concentration of oxygen ?
Umbilical vein.
63
4 year old with diagnosis of aganglionic colon - deficient in which of following neural cells? - she has vomiting, constipation, and abdominal distention.
Postsynaptic parasympathetic neurons. Congential megacolon (Hirschsprung disease) is absense of enteric ganglia in colon - due to failure of neural crest cell migration. Classic symptom described in Q. Is colon not working?
64
to do a laparoscopic appendectomy, what artery needs to be litigated?
Superior mesenteric artery - arises from abdominal aorta at L1. The appendix is an outpocketing of embryonic midgut connected to the cecum - in lower right quadrant.
65
What is esophageal atresia?
congenital disorder where esophogus ends in blind pouch - detected at first feeding.
66
What does the celiac artery supply blood to in embryonic terms
Foregut - from approx lower esophagus to second part of duodenum.
67
What does the inferior mesenteric artery supply in embryonic terms?
Hindgut - from distal portion of trasnverse colon to superior aspect of rectum.
68
failure of differentiation of organs from embryonic foregut would cause malformation in which of following? spleen, gallbladder, asc colon, dec colon, Ileum?
Gallbladder - speen not from gut tube, asc, and ileum from midgut, dec colon from hindgut.
Spleen develops incidentally in the dorsal mesogastrium
69
Malformation of the central tendon in the diaphragm comes from?
Septum transversum
70
What vein drains the embryonic midgut?
superior mesenteric vein. The hepatic portal system collects blood from abd gut tube and spleen and directs flow to liver. Therefore, the distal duodenum, jejunum, ileum, cecum, appendix, asc colona,d prosimarl 2/3 of transverse colon drain via this route.
71
With a perforated ulcer in posterior wall of first part of duodenum, which artery is nearby and possibly damages?
Gastroduodenal.
72
With a left renal and perirenal abscess, which organ is irritated by abscess, and radiating pain to left shoulder?
Diaphragm. closely related to superior pole of left kidney. Visceral sensory fibers convey pain from kidney from t12, L 1 - leads to referred pain in lower abdomen, and thigh - visceral pain is often perceived as cutaneous pain at same spinal cord level as affected abdominal organ. Involvement of diaphragm would refer to left shoulder
73
Dorsal mesentery of esophagus of gut tube forms what structure of the diaphragm?
crura. The crus of diaphragm (pl. crura), refers to one of two tendinous structures that extends below the diaphragm to the vertebral column. There is a right crus and a left crus, which together form a tether for muscular contraction.
74
x
x
75
one year post pregnancy, the medial umbilicus fold contains what structure?
Obliterated umbilical arteries.
76
Which blood vessels supply the embryonic foregut and its derivatives?
Celiac artery. Superior mesenteric (midgut); Interior mesenteric (hindgut); Hepatic portal - drains all three - doesn't supply them; umbilical vein carries blood from placenta to liver and into liver bypass - does not supply gut tube.
77
fetus with midline anterior abd wall defect involving umbilical cord - with intestinal loops and part of liver within membraneous sac - what defect?
Omphalocele - need to finish answer here Q 21
78
rare familial neural defect - involving neural crest cells - which would not be affected by this disorder? pyloric sphincter, abd aorta, teniae coli, diaphragm, hepatopancratic pshyincter?
to do
79
In suprapubic region - using flap for mastectomy, which artery needs to be transected and later grafted?
Inferior epigastric artery
80
A genetically engineered virus selectively attacking cell bodies of post synaptic parasymp neurons - where would virus be most dense? celiac plexus, paravertebral ganglia, myenteric or hypogastric plexus, gray matter of sacral spinal cord segments?
myenteric plexus -
81
loss of weight, upper abd pain radiating to middle/upper back - sclera of eyes are icteric (yellow) reveals tumor in pancreas. Exocrine secretions is blocked from which organ?
liver
82
What does the left gastric artery supply?
Lesser curvature of stomach - forming anastomotic arc with right gastric artery along the lesser curve.
83
Peritoneum referred pain is where?
c3 - c5 dermatomes over shoulder (slides)
84
Projectile nonbilous vomiting one hour after feeding suggests what problem?
Pyloric stenosis - caused by hypertrophy (not error in recanalization), can often be palpitated. More common in males.
85
Histologically, list the four layers of the alimentary canal wall.
Mucosa, Submucosa, Muscularis Externa, Serosa
86
The esophagus starts and ends at what points?
C6 - T11. Upper sphincter, lower
87
Esophageal achalasia - what is it?
A failure of smooth muscle fibers to relax, which can cause the lower esophageal sphincter LES to remain closed.
88
What are the 3 esophageal constrictions and their locations?
Cervical (C5 -6), Thoracic (betw aortic art and left main bronchus), Diaphragmatic T10
89
What does the phrenicoesophageal ligament do?
Permits independent movement of diaphragm and esophagus during respiration and swallowing. The esophagus is attached to its hiatus by this ligament
90
What is a hiatal hernia?
When stomach prolapses the esophageal hiatus. Rarely life threatening
91
What are the two main types of hiatal hernias?
Paraesophogeal and sliding - sliding most common
92
What is a Bochdalek hernia?
Congenital diaphragmatic hernias -
A Bochdalek hernia is a congenital abnormality in which an opening exists in the infant's diaphragm, allowing normally intra-abdominal organs (particularly the stomach and intestines) to protrude into the thoracic cavity.
93
What side do Morgagni hernias normally occur on?
90% right - high mortality rate in infants re causes pulmonary hypoplasia - organs move up into chest.
94
Is there an anatomic sphinchter at the lower end of the esophogas, and what nerves control it?
No, vagus. It is called the esophogastric junction - Z line. LES
95
What is the cardiac orifice?
Where esophagus and stomach join - cardiac sphinter prevents regurgitation
96
What causes GERD?
Functional or mechanical problems of LES (lower esophogal sphincter - made of a bundle of muscles) - are most common - transient relaxation can be caused by foods, drugs, hormones (progesterone), nicotine
97
Are the les and z line the same?
One is the location of the lower esophageal sphincter (LES) or gastroesophageal junction. The second is the upper end of the squamo-columnar junction (Z line),which now (with Barrett's) is in the esophagus (moved north).
98
What is Barrett's Esophagus?
A condition where the tissue lining is replaced by a lining similar to the intestinal tract, caused by chornic esophagitis. (Columnar metaplasia). Most patients would have GRD and hiatus hernia or mid/high ulcer.
99
What nerves innervate the esophagus?
Sympathetic T 1 - 10, para Vagus afferants
The esophagus is innervated by the vagus nerve and the cervical and thoracic sympathetic trunk. The vagus nerve has a parasympathetic function, supplying the muscles of the esophagus and stimulating glandular contraction.
100
Lymphatics of esophogus?
Prox third - deep cervical nodes - thoracic duct; mid third - superior and posteria mediastinal nodes; distal third, follow left gastric artery to gastric and celiac lymph nodes
101
Two acids in stomach?
Pepsin (protein digesting) HCI (helps kill bacteria - hydrochloric acid). simple columnar epithelium, secretes bicarbonate buffered mucus
102
Nutrients from stomach not waiting to be absorbed in small intestine?
Water, electrolytes, some drugs (aspirin) , and alcohol
103
List order of pyloric parts starting from the duodenum.
Pylorus, pyloric sphincter, pyloric canal, pyloric atrium
104
Can gastric and duodenal ulcers be distinguished based upon history alone
No - although some findings are suggestive.
105
When is testing for H pylori infection necessary?
to determine if have peptic ulcer - rapid urease tests best choice
106
What is one mark of a benign stomach ulcer?
ulcer projects out beyond normal expected lesser curvature.
107
STARTING at Q 22 of Greys
here we go
108
Patient diagnosed w/ inguinal hernia. During operation loop of intestine found passing through deep inguinal ring - what kind of hernia is it?
Indirect hernia results from intestines coming through deep inguinal ring. Direct penetrate the anterior abd wall MEDIAL to inferior epigastric vessels through inguinal triangle and DO NOT penetrate deep ring.
109
perforating ulcer in stomach, posterior wall - where would peritonitis most likely develop initially?
Omental bursa is directly posterior to stomach. Pouch of Morison (subhepatic space) is behind liver and anterior to right kidney;
110
Which venous tributaries to portal system anastomoses w/ caval veins to causes varices in esophagus?
Left gastric vein carries blood from stomach to portal vein. At junction, left gastric vein (portal system) anastomoses with esophageal veins (caval system)
111
severe abdominal pain, cremasteric reflect notedly absent - which nerves is responsible for efferent limb of this reflex?
Genitofemoral from vental rami L1 and L2. Ilioinguinal arises from L1 and supplies skin over root of penis and upper part of scrotum. Pudendal innervates external genitalia.
112
exploratory lapartomy - where would incision likely be made to separate left and right rectus sheaths
Linea alba
113
After a tummy tuck, which layer of abdominal wall will hold the sutures?
Scarpas. Thick and tough.
114
Tumor in head of pancreas - which structure is likely obstructed?
Common bile duct is located at the head of the pancreas and receives contents from the cystic duct and hepatic duct. . An obstruction here backs up bile with pain and jaundice.
115
man admitted - excessive vomiting and dehydration - xray shows part of bowel is being compressed between abd aorta and superior mesenteric artery - which intestinal structure is most likely being compressed?
Third part of duodenum,
116
During surgical repair of perforated duodenal ulcer, the gastroduodenal artery is ligated - what branch of what artery will continue to supply blood to the pancreas?
Superior mesenteric artery.
117
alcoholic, bleeding from esophogael varices, Varices most likely a result of anastomoses between left gastric vein and which other vessels?
left gastric vein and esop veins of azygos form important link when portal vein backing up. Portal caval anastamoses.
118
Excruciating pain in back and left shoulder - abscess in upper part of left kidney - The shoulder pain may be caused by spread of inflammation from what structure?
Diaphragm
119
which anatomical features is most useful to distinguish the jejunum from the ileum?
Jejunem has less mesenteric fat.
120
severe diarrhea, 90% blockage of inferior mesenteric artery from aorta - which artery will provide collateral supply to desc colon?
middle colic artery. via marginal?
121
dull aching pain in umbilical region, and flexion of the hip causes sharp pain in lower abd quadrant - which structure is most likely inflamed?
appendix. psoas sign makes sense re iliopsoas muscle group lies directly beneath appendix.
122
Excruciating pain in back and left shoulder - abscess in upper part of left kidney - The shoulder pain may be caused by spread of inflammation from what structure?
Diaphragm
123
Dull pain, tumor at head of pancreas - abdominal pain is mediated by afferent fibers that travel initially with which of the following nerves?
Greater thoracic splanchnic nerve arising from T5 - T9
124
Severe antherosclerosis, low sperm count - which artery is most likely occluded?
Testicular artery.
125
malignancy in scrotum, which of following are the
| first lymph nodes affect area?
Superficial inguinal nodes.
126
which component of spermatic cord is derived from internal abd oblique muscle?
cremaster muscle.
127
Do neural crest cells give rise to adrenal medulla or adrenal cortex?
Medulla
128
Does nerepinephrine or dopamine increase cardiac output?
nerepinephrine
129
What neurotransmitter is the most common excitatory one in the CNS?
Glutamate
130
Does GABA or dopamine inhibit cardiac output in the CNS?
both
131
What is a perinuerium?
Each bundle of nerves is surrounded by one, consisting of several layers of epithelial cells.Tight junctions exclude most macromolecules
The tight junctions provide selective barrier to chemical substances. The perineurium is a smooth, transparent tubular membrane which may be easily separated from the fibers it encloses. In contrast, the epineurium is a tough and mechanically resistant tissue which is not easily penetrated by a needle.
132
What does the epineruium surround?
Many fascicles, but does not exclude macromolecules - it is an external coat of nerves.
133
What is the layer of reticular fibers that covers each individual nerve fiber?
endoneurium - which does not exclude macromolecules.
134
What is the neurotransmitter for preganglionic sympathetic and pre and post ganglionic parasym synapsis?
ACh
135
What are Nissi bodies composed of and where do they reside?
Only in neurons, large granular basophilic bodies of RER and polysomes.
136
What is the axon hillock made of?
it contains microtubules arranged in bundles and permits passage neurofilaments, mitochondria, and vesicles into the axon.
137
Do synaptic vesicles become incorporated into the presynaptic membrane or enter the synaptic cleft?
They become incorporated - releasing neurotransmitters via exocytosis
138
What disease is associated with demyalinization in the CNS and retina?
MS
139
What disease is characterized by tremors, muscular rigidity, difficulty in movement, and what is its cause?
Parkinsons. Loss of dopaminergic neurons from the substantia nigra possibly due to poisons and envionmental factors.
140
What disease is associated with loss of neurons that produce the neurotransmitter GABA
Huntingtons - a fatal heredity disease becoming evident in the third or fourth decade of life.
141
Is viral or bacterial meningitis more serious?
bacterial. Death can occur within 24 hours.
142
Does depolarization trigger the opening of voltage gated K+ channels?
Yes. Voltage-gated potassium channels are activated by depolarization, and the outward movement of potassium ions through them repolarizes the membrane potential to end action potentials, hyperpolarizes the membrane potential immediately following action potentials, and plays a key role in setting the resting membrane
143
Is Hirschsprung disease characterized by a dilated retina or colon?
Colon - caused by the absence of parasympathetic myenteric ganglia known as Auerback plexus.
Hirschsprung disease (HSCR) is a birth defect. This disorder is characterized by the absence of particular nerve cells (ganglions) in a segment of the bowel in an infant. The absence of ganglion cells causes the muscles in the bowels to lose their ability to move stool through the intestine (peristalsis).
144
Why is the arcuate line is important?
It is the site of entry of the inferior epigastric artery into the rectus sheath.
145
What is Hesselbach's triangle?
Common site for direct hernias - area of potential weakness. Bound medially by linea semilunaris, laterally by inferior epigastric vessels, and interiorly by inguinal ligament
146
What is the Superficial Inguinal Ring
A triangular opening in the aponeurosis of the external oblique muscles that lies just lateral to the pubic tubercle.
147
What a aponeuroris?
A sheet of pearly white fibrous tissue that takes the place of a tendon in flat muscles having a wide area of attachment.
148
What is the deep inguinal Ring?
Lies in the transversalis fascia, just lateral to the inferior epigastric vessels
The two openings to the inguinal canal are known as rings. The deep (internal) ring is found above the midpoint of the inguinal ligament. which is lateral to the epigastric vessels. The ring is created by the transversalis fascia, which invaginates to form a covering of the contents of the inguinal canal.
149
What is the inguinal Canal?
connects deep and superficial inguinal ring - transmits spermatic cord or round ligament of uterus and genital branch of genitofemoral nerve - both of which run through the deep inguinal ring and inguinal canal.- An INDIRECT HERNIA also passes through.
150
Does the ilioinguinal nerve run through the inguinal canal?
Yes, but not through the deep inguinal ring.
151
Describe the differences between Reducible, Incarcerated and Strangulated hernias
Reducible - content can be returned; Incarcerated - trapped or stuck in groin - irreducible; Strangulated - life threatenening - tissues twisted and will turn gangrenous.
152
Indirect Inguinal hernia
congenital - descends into scrotom, LATERAL to inf. epig vessels - more common than Direct. - passes through deep ring, canal and superficial
153
Direct hernia
through weakened area of abdominal - MEDIAL to inf epig vessels - rarely descends to scrotum. Older men get them because of weakened transverse muscles. ?
154
What is the spermatic cord composed of?
The spermatic cord contains the ductus deferens (vas deferens), the testicular artery and the pampiniform plexus of veins. Other structures in the cord are the cremasteric artery, the artery to the vas, nerve to the cremaster, sympathetic nerves and the lymphatics of the testis and epididymis.
155
What is the Processus Vaginalis Testis?
fetal structure -
The processus vaginalis (or vaginal process) is an embryonic developmental outpouching of the peritoneum. It is present from around the 12th week of gestation, and commences as a peritoneal outpouching. n males, it precedes the testis in their descent down within the gubernaculum, and closes.
156
What happens if around birth the processus vaginalis testis fails to close?
can lead to congenital indirect inguinal hernia, may cause fluid accumulation (hydrocele processus vaginalis) if occluded
157
What is the inntermost layer of the scrotum?
Tunica Vaginalis
158
What are the peritoneal reflections?
Omentum (Lesser, Greater), Mesenteries (Proper - small intestine; Transverse mesocolon; Sigmoid mesocolon; Mesoappendix); other Peritoneal Ligaments - (5) and Peritoneal Folds ( 3)
159
What is Peritonitis?
Inflammation/infection of pertitoneum - commonly caused by burst appendix, a perforating ulcer, or poor sterile techniques during abd surgery - NEEDLE insert - McBurney's Point - avoiding epigastric vessels.
160
Is the peritoneal cavity sealed?
Only in males - hence females can get infections through... vagina and uterine tubes. Is there something more here?
161
What is the Pouch of Douglass - and do only males have it?
Only females:
The rectouterine pouch, also known as the rectovaginal pouch, cul-de-sac or pouch of Douglas, is an extension of peritoneum between the posterior wall of uterus and the rectum in females. It is the most dependent part of the peritoneal cavity and is analogous to the rectovesical pouch in males.
162
What is Morrison's Pouch?
An area between your liver and your right kidney. It's also called the hepatorenal recess or right subhepatic space. Morison's pouch is a potential space that can open up when fluid or blood enters the area
163
What is the Lesser Sac and where is it?
"Omental Bursa" - a space behind liver, lesser omentum, stomach, and upper greater omentum - CLOSED sac except communication with Greater Sac through epiploic (omental) foramen.
164
How many recesses does the Lesser Sac have?
three - superior, inferior, and splenic
165
what is the Greater Sac?
Extends across abdomen - with many recesses into which pus can live - Subphrenic (between diap and anterior/superior liver - separated into two by Falciform Ligament; Subhepatic (Morrison's pouch) - betwe liver and kidney and suprarenal gland - communicates with Lesser Sac via epiploic foramen and right paracolic gutter - thus the pelvic cavity, Paracolic (Gutters) - lateral to ascending colon (right recess) and lateral to descending (left)
166
What is the epiploic or Omental (Winslow's) Foramen?
natural opening between lesser and greater sacs - DAVE - Duct, Artery, Vein, Epiploic foramen -
anterior: the free border of the lesser omentum, known as the hepatoduodenal ligament. This has two layers and within these layers are the common bile duct, hepatic artery, and hepatic portal vein.
167
What do peritoneal reflections do?
support the viscera and provide pathways for associated neurovascular structures. - include omentum (lesser, greater), 4 mesenteries, and 5 Ligaments and 3 folds
168
What is a Pott's fracture?
Fibula and tibia - damage to their distal ends.
169
What is a Colles fracture?
Radius near wrist.
170
Three sources of new bones when healing?
Periosteum (majority), endosteum, bone marrow (will need to take time to differentiate) - especially the pluripotent stem cells.
171
What are diathroses vs. synarthroses joints?
Diathroses - a lot of movement (knee, elbow)
172
What is Pannus?
In rheumatoid arthritis, where synovial membrane lining thickens and is changed to a villae-type inflammatory connective tissue.
173
What is the cause of rheumatoid arthritis?
Rheumatoid arthritis is an autoimmune disorder -
Peptide antigen presented to T cells (DC4+) releasing Interfeuron 15 activating synovial macrophages that secrete proinflammatory cytokines, which then release collagenase and matrix metalloproteases - Neutrophils contribute prostaglandins, proteases and reactive oxygen species tarted to the destruction of the articular cartilage and subjacent bone tissues.
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What is an ascites?
Abnormal buildup of fluid in the abdomen.
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What is Morrison's pouch?
Morison's pouch is an area between your liver and your right kidney. It's also called the hepatorenal recess or right subhepatic space. Morison's pouch is a potential space that can open up when fluid or blood enters the area.
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What is the Pouch of Douglass?
The rectouterine pouch, also known as the rectovaginal pouch, cul-de-sac or pouch of Douglas, is an extension of peritoneum between the posterior wall of uterus and the rectum in females. It is the most dependent part of the peritoneal cavity and is analogous to the rectovesical pouch in males.
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What is osteopetronis?
Stone bone - failure of OClasts or hormones associated w/, lack of ruffled border - very thick bones, fills in medulary cavity - then lack of marrow, and lack of RBC/WBC production.
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Cleidocranial dysplasia - what is it?
Affects development of bones and teeth - Lack of or mutation in RUNx2, hypoplastic clavicles, delayed ossif of sutures - cartilagous skeletons in mice. Some have extra pieces of bone called Wormian bones within the sutures.
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What is osteogenesis imperfecta?
Many kinds - Collagen Type 1 deficiency - gene mutation - , Brittle Bone - blue sclera, hearing loss, seizures, OSx deficiency, ectopic cartilage formation under bone collar. Affects Collagen Type I mutation
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What are rickets vs. Osteomalacia?
Vitamin D and calcium deficiency - rickets in children, growth place wides - soft osteoid, bones bow and bend
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Scurvy is caused by what vitamin deficiency and what does it do?
C - Disrupts growth plate - vitamin C needed for collagen. Early symptoms of deficiency include weakness, feeling tired and sore arms and legs. Without treatment, decreased red blood cells, gum disease, changes to hair, and bleeding from the skin may occur.
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What is achondroplasia?
Problem in chondrocytes - poorly formed growth plates - limbs short and stunted.
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What is osteofibrosa?
CA up - Excessive fibrous tissue w/ many Oclasts - bone transparent in xrays. Loss of calcium in bones - makes them fragile.
Osteitis fibrosa cystica is the result of unchecked hyperparathyroidism, or the overactivity of the parathyroid glands, which results in an overproduction of parathyroid hormone (PTH). PTH causes the release of calcium from the bones into the blood, and the reabsorption of calcium in the kidney.
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What is osteoporosis?
bone quality goes down - two types - menopausal women (lack of estrogen) and elderly - lack of zinc.
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What is Acromegaly?
bones grow thick due to excess human growth hormone in pituitary- GH - causes excess IGH - large hands, feet and face.
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What are malignant bone tumors called, who gets them and where are they located?
osteosarcoma - young adults, femur, humerus
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Jansen's Disease- 20 cases in the world, what is it?
PTH mutation - rare autosomal dominant disorder characterized by short-limbed dwarfism and severe, agonist-independent hypercalcemia. Four different mutations in the gene encoding the PTH/PTHrP receptor (PTHR1) were identified in several unrelated JMC patients
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How does hyperparathyroidism effect bones?
Excessive bone resorption. Overactivity of the thyroid gland, resulting in a rapid heartbeat and an increased rate of metabolism.
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What does excess of Human Growth Factor bode?
Gigantism, or dwarfism if insufficient. HGH calls out IGFs, IGFs promote cell division in growth plate.
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What is the different between osteoarthritis and rheumatoid arthritis?
Rheumatoid - immune system attacks the synovium - changing membrane to villae-type. A chronic progressive disease causing inflammation in the joints and resulting in painful deformity and immobility, especially in the fingers, wrists, feet, and ankles. Osteroarthritis comes from USE over time.
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What is mneumonic for growth plate process?
Real People Have Career Options
| Resting zone, Proliferative zone, Hypertrophic cartilage zone, Calcified cartilage zone, Ossification zone.
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Describe the four layers of the alimentary canal - from esophagus to anal canal -
MSMS - Mucosa, Submucosa, Muscularis Externa, Serosa
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What is McBurney's Point?
Marks BASE of appendix.Site of maximum pain and tenderness in acute appendicitis. Junction of the outer 1/3 and middle 1/3 of an imaginary line between the umbilicus and anterior superior iliac spine
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What is Addison's plane?
The transpyloric plane, also known as Addison's plane, is an imaginary axial plane located midway between the jugular notch and superior border of pubic symphysis, at approximately the level of L1 vertebral body.
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What are esophageal varices?
Enlarged veins in the esophagus. They're often due to obstructed blood flow through the portal vein, which carries blood from the intestine, pancreas and spleen to the liver.
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What is caput madusea?
Caused by portal hypertension - recanalized ligament of teres (in females) - and travels to superfilicial periumbilical veins. Sx of portal hypertension.
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What causes anal rectal hemorrhoids?
Portal hypertension- blood backflows through superior rectal vein -
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What are the three main places one finds sinusoid capillaries (the most permeable)?
The liver, spleen and red blood marrow. Traps old RBC (120 days).
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In liver, what's the percentage of hepatic portal vein blood to hepatic artery blood?
75/25
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What is Annular Pancreas?
A rare condition in which the second part of the duodenum is surrounded by a ring of pancreatic tissue continuous with the head of the pancreas. This portion of the pancreas can constrict the duodenum and block or impair the flow of food to the rest of the intestines.
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What is the difference between interstitial and appositional growth in bone?
Interstitial increases length, Appositional increases in width.
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What is the difference between intramembranous and endochondral ossification?
In intramembranous ossification, bone develops directly from sheets of mesenchymal connective tissue. In endochondral ossification, bone develops by replacing hyaline cartilage. ... Appositional growth allows bones to grow in diameter.
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What is endochondral ossification?
The process by which growing cartilage is systematically replaced by bone to form the growing skeleton.
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What are the six steps of endochondral ossification?
Step 1
Cartilage enlarges; Chondrocytes die
Step 2
blood vessels grow into perichondrium; cells convert to osteoblasts; shaft becomes covered with superficial bone
Step 3
more blood supply and osteoblasts; produces spongy bone; formation spreads on shaft
Step 4
Osteoclasts create medullary cavity; appositional growth
Step 5
epiphysis centers calcify; blood and osteoblasts move in; secondary ossification centers
Step 6
Epiphysis filled with spongy bone; cartilage remains at joints; epiphyseal plate in metaphysis
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What is GFAP?
A type III intermediate filament protein that is expressed by numerous cell types of the central nervous system (CNS), including astrocytes and ependymal cells during development.
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Effects of IGF-1 on bones:
Ups Oblast and Oclast activity, thus increasing endochondral ossification. Increases collagen type 1 and proteoglycans. - It also increases interstitial bone growth by acting on cartilage to proliferate, increas size and differentiation of chondroblasts.
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How does appositional bone growth occur?
Osteoblasts in the periosteum deposit new bone matrix layers onto already-formed layers of the outer surface of bone. ... This results in a greater concentration of bone being built than being destroyed, which produces thicker and stronger bones.
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What does GH do in the liver to promote bone growth?
Facilitates creation of IGF-1. This is where IGF-1 is created.
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What does FAST stand for in the ER room re trauma?
```
Focused assessment with sonography for trauma (FAST) is a rapid assessment type of ultrasonography which includes evaluations of:
The hepatorenal recess (Morison pouch)
The perisplenic area
The subxiphoid pericardial space
Suprapubic area (Douglas pouch)
```
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Why is the arcuate line important and where is it?
It is roughly positioned half way between the umbilicus and the pubic crest. Clinically, the arcuate line is important as the site of entry of the inferior epigastric artery into the rectus sheath.
The inferior one-quarter (below the arcuate line) of the rectus sheath is supported posteriorly only by the transversalis fascia, extraperitoneal fat, and the peritoneum
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what is the rectus sheath?
The rectus sheath, also called the rectus fascia, is formed by the aponeuroses of the transverse abdominal and the internal and external oblique muscles. It contains the rectus abdominis and pyramidalis muscles. It can be divided into anterior and posterior laminae.
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What is the inguinal canal, and how is it formed?
The inguinal canal is formed in relation to the relocation of the testis during fetal development.
The inguinal canal in adults is an oblique passage approximately 4 cm long directed inferomedially through the inferior part of the anterolateral abdominal wall.
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Where are the inguinal rings located?
Superficial inguinal ring
A triangular-shaped defect in the aponeurosis of the external abdominal oblique and lies immediately above and medial to the pubic tubercle
Deep inguinal ring
An oval opening in transverse fascia and lies approximately 1.5cm above midpoint of inguinal ligament lateral to inferior epigastric vessels
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What structures run through the inguinal canal?
In males
Spermatic cord
Ilioinguinal nerve
In females
Round ligament of uterus
Ilioinguinal nerve
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What does the The ilioinguinal nerve innervate?
The anterior surface of the scrotum or labia majora, root of the penis or mons pubis, and a small portion of the upper antero-medial thigh. It also innervates the internal oblique and transversus abdominis muscles.
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What nerve innervates the penis?
The pudendal nerves supply somatic motor and sensory innervation to the penis. The cavernous nerves are a combination of parasympathetic and visceral afferent fibers and provide the nerve supply to the erectile tissue.
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What are the three layers of the spermatic cord?
Covered by three concentric layers of fasciae
External spermatic fascia: It is derived from the external oblique muscle. It attaches to the margins of superficial inguinal ring.
Cremasteric fascia: It is derived from the internal oblique muscle. It covers the cremaster muscle.
Internal spermatic fascia: It is derived from the fascia transversalis (fascia covering the transversus abdominis muscle). It is attached to the margins of the deep inguinal ring.
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What is the spermatic cord?
The spermatic cord is the cord-like structure in males formed by the vas deferens (ductus deferens) and surrounding tissue that runs from the deep inguinal ring down to each testicle. Its serosal covering, the tunica vaginalis, is an extension of the peritoneum that passes through the transversalis fascia.
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What are the contents of the spermatic cord?
Contents
Vas deferens (Ductus deferens):
Thick walled muscular duct.
Transports spermatozoa from epididymis to urethra.
Testicular artery:
A branch of abdominal aorta arising at the level of second lumbar vertebra.
Supplies blood to testis and epididymis.
Testicular veins (Pampiniform plexus):
From the Pampiniform plexus (testis).
Becomes reduced in size as it ascends.
At the deep inguinal ring, only a single vein is left (testicular vein).
Drains into the left renal vein on the left side and into the inferior vena cava on the right side.
Testicular lymph vessels:
Ascend through the inguinal canal and pass up over the posterior abdominal wall to reach the lumbar (para-aortic) lymph nodes.
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What nerve supplies the creamaster muscle?
Genital branch of genitofemoral nerve.
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What is the Processus vaginalis?
An embryonic developmental outpouching of the peritoneum. The remains of it are present within the spermatic cord.
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What nerves innervate the testis?
The somatic supply to the testes and scrotum originates from the L1–L2 and S2–4 nerve roots through the iliohypogastric, ilioinguinal, genitofemoral, and pudendal nerves The iliohypogastric nerve provides sensory innervation to skin above the pubis.
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What's the most common cause of scrotal enlargement?
Hydrocele - fluid accumulation in the tunica vaginalis (potential space).
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What is varicocele of the scrotom?
An abnormal dilation and tortuosity in the pampinafour venous plexus - can be seen when patient standing. Usually on left because vein drains to left renal vein rather than right's drainage to larger IVC.
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What are the most common types of hernias?
Approximately 75% of all hernias are inguinal; of these, 50% are indirect (male-to-female ratio, 7:1), with a right-side predominance, and 25% are direct
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Where do indirect (congenital) hernias occur?
Lateral to inferior epigastric vessels - passing through deep inguinal ring and as a protrusion along the spermatic cord.
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Where do direct hernias occur?
Occurs medial to the inferior epigastric vessels, passes directly through the posterior wall of the inguinal canal, and is separate from the spermatic cord and its coverings derived from the abdominal wall
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Where is referred pain on the DPH?
C3 -5 dermatomes over the shoulder -
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Is visceral peritoneum sensitive to anything?
YES, to stretch and chemicals. Pain often referred to midline - poorly located.
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What are the structures of the female that lead into the peritoneal cavity?
The uterine tubes, the uterus, and the vagina
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What are the primary retroperitoneal organs (never had a mesentery)?
Kidney, Adrenals, Ureters, Aorta, IVC, Rectum, Anal Canal.
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What organs lost a mesentery during development?
Duodenem (2 and 3); Head, neck and body of pancreas; Asc and Desc Colon, Upper rectum
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What are the Major Intraperitonial Organs (suspended by mesentery)?
Stomach, Liver and gallbladder, spleen, duodenum (1st part), tail of pancreas, Jejunum, ileum, appendix, transverse colon, sigmoid colon
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What structures does the Lessor Omentum create?
2 Structures - hepatogastric ligament (from porta hepatis to lesser curvature of stomach; Hepatoduodenal ligament - from porta hepatis to superior duodenum, - CONTAINS common bile duct, proper hepatic a and hepatic portal vein.
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Where and what is the omental foramen?
behind right border of hepatoduodenal ligament.. Also called foramen of Winslow and is the passage of communication between the greater sac (general cavity (of the abdomen)), and the lesser sac.
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What is the difference between the lesser sac and the lesser omentum?
The lesser sac (omental bursa) is behind the lesser omentum and stomach. It allows the stomach to move freely against the structures posterior and inferior to it. The omental bursa is connected with the greater sac through an opening in the omental bursa - the epiploic foramen (of Winslow).
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What is peritonitis?
An inflammation of the serosal membrane that lines the abdominal cavity and the organs contained therein - numerous causes.
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What is the greater sac?
Also known as the general cavity (of the abdomen) or peritoneum of the peritoneal cavity proper, is the cavity in the abdomen that is inside the peritoneum but outside the lesser sac.
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What is mesentery?
Folds of peritoneum that support and stabilize the intraperitoneal GI tract organs. Blood vessels, lymph vessels, and nerves are sandwiched between the two folds and supply the digestive organs.
There are several different types of mesenteries:
Omenta
Ligaments
Mesentery Proper
Mesocolons
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What does the small intestine mesentery do?
It has a 4 to 6 meter periphery, which covers the entire length of the jejunum and ileum and attaches to the posterior abd wall. (looks like an octopus - in a fan shape - really embracing above sections of small intestine - anchoring them.
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What are the various mesenteries other than the small intestine?
Triangular (ileum to appendix), transverse mesocolon, sigmoid mesocolon; Liver ligaments - falciform, coronary, left and right triangular , round (remnant of fetal umbilical vein), hepatoduodenal (portion of lesser omentum enveloping the portal triad)..
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What's the portal triad and where is it?
The hepatic artery proper, the hepatic portal vein and the common bile duct in the hepatoduodental lilament (portion of lesser omentum).
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What does the falciform ligament divide?
Anterior right and left lobes of liver.
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What are the four ligaments of the spleen?
Gastrosplenic ligament
A double layer of peritoneum that connects the fundus of stomach to hilum of spleen.
In this double layer of peritoneum are the short gastric and left gastroepiploic vessels
Splenorenal ligament
Extends between the hilum of spleen and anterior aspect of left kidney.
The splenic vessels lies within this ligament, as well as the tail of pancreas
Phrenicosplenic ligament
A double fold of peritoneum (mesentery) extending between the diaphragm and spleen; this is a portion of the greater omentum
Splenocolic ligament
Connection between the splenic capsule and the transverse colon
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What are the ligaments of the stomach?
Hepatogastric ligament
The part of the lesser omentum that extends between the liver and lesser curvature of the stomach
Gastrosplenic ligament (See Spleen)
Gastrophrenic ligament
The portion of the greater omentum that extends from the greater curvature of the stomach to the inferior surface of the diaphragm
Gastrocolic ligament
From the greater curvature of the stomach to the transverse colon (anterior wall of lessor sac)
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Are there various peritoneal subdivisions?
Yes, including the Pouch of Morrison behind the right kidney - Right infrahepatic recesses = hepatorenal recess = Pouch of Morison!
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What do the transverse colon and transverse mesocolon divide?
The greater sac into supracolic and infracolic compartments.
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What is the difference between the Left and Right suprahepatic recesses?
The left suprahepatic recesees include the
left anterior and posterior suprahepatic spaces
Right suprahepatic recesses included the
right anterior and
right posterior suprahepatic spaces and the
bare area of liver (extraperitoneal space)
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What are other peritoneal subdivisions?
Infrahepatic, Right (Pouch of Morrison) Left infrahepatic, and the Infracolic compartments - right and left paracolic sulcus (gutters), and the right and left mesenteric sinus
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What is paracentesis?
Use a needle - Liquid that accumulates in the abdomen is called ascites. Ascites seeps out of organs for several reasons related either to disease in the organ or fluid pressures that are changing
There are two reasons to take fluid out of the abdomen
To analyze it for diagnostic purposes
To relieve pressure.
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What is the route of somatic abdominal pain?
Central part of the diaphragm: Phrenic nerve (C3, 4, and 5)
Peripheral part of the diaphragm: Intercostal nerves (T7 to 11)
Anterior abdominal wall: Thoracic nerves (T7 to 12) and the 1st lumbar nerve
Pelvic wall: Obturator nerve (L2, 3, and 4)
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What are the three types of abdominal pain?
Somatic from skin, fascia, muscle and parietal - can be severe and precisely localized - when origin is on one side of midline, pain is also lateral.
Visceral from organs, viscera and mesentery - cause can be stretching, distention ischemia and chemical pain (ie gastric juices) - is dull and poorly localized
Visceral is referred to midline - colic is a form - often because of lumen occlusion - ie gallstone, intestinal obstruction, etc
Referred pain - for both somatic and visceral
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Where is referred pain for heart?
left chest cavity, down left arm.
254
Referred pain for lungs and DPH?
neck and collar area - shoulders and clavicles -
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Referred pain of spleen
Left shoulder
256
Referred pain of ovaries?
both sides of umbilicus and down a bit.
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Referred pain for kidneys?
from waste down like a skirt, into inner and outer thighs.
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Referred pain for ureters
Lower than bladder - pelvic girdle
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What is Meckel's diverticulum?
An outpouching or bulge in the lower part of the small intestine ( the ILEUM). The bulge is congenital (present at birth) and is a leftover of the umbilical cord. Meckel's diverticulum is the most common congenital defect of the gastrointestinal tract.
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Meckel's diverticula, vitelline cysts, or vitelline fistulas are most commonly found in association with with organ?
The Ileum.
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During development of the gut, are the smooth muscle in the wall of the esophagus is derived from somatic or splanchnic mesoderm?
Splanchnic.
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Lateral plate mesoderm gives rise to what?
The body cavity. On either side of the intermediate mesoderm resides the lateral plate mesoderm. Each plate splits horizontally into the dorsal somatic (parietal) mesoderm, which underlies the ectoderm, and the ventral splanchnic (visceral) mesoderm, which overlies the endoderm.
Paraxial mesoderm – which forms somitomeres and somites
Intermediate mesoderm – which contributes to the urogenital system
Lateral plate mesoderm – which is involved in forming the body cavity
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Where is the coronary ligament?
Liver.
264
Ruptured spleen - surgery needed, what peritoneal structure must be carefully manipulated to avoid intraperitoneal bleeding?
Splenorenal ligament.
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Kidney stone obstructing right ureter - severe pain radiating from lower back toward pubic symphysis - at which point is the calculus most likely to lodge?
Pelvic brim.
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Lower portion of descending colon needs to be removed - which vessels and nerves will be cut during operation?
Pelvic splanchnic nerves and left colic artery supply desc colon.
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two weeks after appendectormy, male complains of numbness of skin over pubic region and anterior portion of genitals, which nerves were most likely injured?
ilioinguinal nerve is a terminal branch of spinal nerve L1. Innervates skin overlying iliac crest and upper inner thigh (not the cremaster nerve FYI - that is genitofemoral). Can be injured with extension of appendectomy incision.
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5 year old, projective vomiting, severe dysphagia - two days later aspiration pneumonia - webs and strictures in distal third of thoracic esop - ?
Esophogal stenosis results from failure or recanalization in 8th week, which may also cause esophageal atresia. webs and strictures in esop are found w/ stenosis, but not in atresia.
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vomitus of 5 day old infant contains stomach contents and bile - 4th part of duodenum has stenosis, child cries all the time, not gaining weight?
duodenal stenosis caused by incomplete recanalization of duodenum. other options above this would not create bile, i.e. hypertrophied pyloric sphincter, patent bile duct, atrophied gastric antrum.
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4 day old, vomiting, no bile - distressed, sucking movements w/ lips, failing to thrive - ?
hypertrophy of pyloric sphincter - projectile vomited with stomach contents but no bile. Duodental atresia, like stenosis, causes vomiting of stomach but vomiting begins soon after birth in atresia - stenosis does not begin and can occur days after delivery.
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5 day old, vomit stomach contents and bile - 2 days of vomiting, xray - stenosis in third part of duodenum - ?
Incomplete recanalization of duod caused either by duod stenosis or partial occlusion of lumen of duod and usually occurs in distral third portion of duod.
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2 hour old diagnosed in-utero with polyhydramnios - now vomiting w/ bile - and xray shows double bubble, constantly hungry, losing weight?
Duodenal atresia is the result of a failed reformation of lumen of duod - with vomiting within first few days of birth. Polyhyd present. double bubble is a sign because of distended gas filled stomach. Duod stenosis is caused by incomplete recanalization of duod
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4 year old, severe vomiting, xray reveals annular pancreas - what is the typical explanation?
caused duod obstruction due to thick band of pancreatic tissue that surrounds and constricts second part of duod. Both buds have to be involved - any answer with only one of the buds - dorsal or ventral - is wrong - needs both.
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during emergency appendectomy, surgeon notes 5cm long fingerlike pouch on anterior border of ileum near ileocecal junction - this pouch is remnant of what?
Omphaloenteric duct, vitalline. It is NOT a remnant of the umbilical cord.
275
3 month old admitted with abnormal mass of tissue protruding from abdomen. xray shows it contains some greater omentum and small intestine - mass proturdes when infant cries, strains and coughts - what is based explanation?
Umbilical hernia - a defect in the linea alba. Differs from omphalocele - as there is a failure of intestine to return to abd cavity - without a covering of hernia of the skin. In umbilical hernia - structures are covered by skin. Gastroschisis is an imcomplete closure of the lateral foldes - resulting in an epigastrric hernia where organs protrude into the amniotic cavity - surrounded by amniotic fluid. An indirect inguinal hernia si when the communcation betwe the tunica vaginalis and peritoneal cavity do not close, and a loop pof intestine or portion of other oragn herniates through the deep inguinal ring into the inguinal canal with possible further descent thru the superficial inguinal ring into scrotum or lambium majus.
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fetal defect - on right side, lateral to median plane, viscera protrude into amniotic cavity - What explains this?
Gastroschisis, an incomplete closure of the lateral folds during the 4th week.
277
What does nonrotation of the midgut result in?
the lower portion of the loop returning to the abdomen first, the small intestine passing to the right side of the abdomen and the large intestine lying entirely on the left.
278
When the cloacal membrane ruptures during the 8th week, what happens?
A communication between the anal canal and amniotic cavity.
279
2 hour infant vomits stomach content and bile - abdominal distention, unable to pass meconium - what is the most common cause?
obstruction in fetal bowel - midgut volvulus results in twisting of intestine and bowel obstruction, small or large intestine.
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what is the most common cause of Mecke's diverticulum?
Remnant of oomphaloenteric duct.
281
newborn has no passage of first meconium stool for 48 hours after birth - . Exam reveals anal agenesis w/ perineal fistula - what is most common explanation?
Incomplete separation of cloaca by urorectal septum. Failure of anal membrane to perforate results in inperforate anus.Abnormal recanalization of colon results in rectal atresia where there is NO connection between rectum and anal canal.
282
anal stenosis diagnosis, after infant lacking stool for ten days - what is most likely cause?
Dorsal deviation of urorectal septum results in anal stenosis.
283
2 month old infant presents with fecal discharge from umbilicus - best explanation?
failure of ureteric bud to form results in renal agenesis and oligohydramnios.
284
5 day old infant diagnosed with anorectal agenesis - ultrasound reveals rectourethral fistula - what is most likely embryoligic cause?
Anorectal agenesis - due to abnormal partitioning of cloaca, often associated with recto-type fistulas.
285
12 year old massive rectal bleeding - free of pain, reveals meckle diverticulum, what is the underlying embryoligcal cause?
Remnant of yolk stalk.
286
pregnant woman, ultrasound - unilateral renal agenesis and oligohydramnios - what condition is most likely?
Failure or ureteric bud to form. Ureteric duplication occurs due to premature division of ureteric bud and can also result in a double kidney. Wilms tumor is a malignancy of the kidney more common in children.
287
15 year old female with bilateral inguinal masses. No period yet but normal breast development - external genitalia feminine - shall vagina, no uterus - sec chromatin pattern was negative - what is best diagnosis? -
Androgen insensitivity syndrome involves the development of testes and female external genitalia with a blind ending vagina and absence of uterus and uterine tubes. Male and female pseudohermaphroditism have different presentation and result from 46 xy and 46 xx genotypes.
288
female gymnast with pelvic pain - history of primary amenorrhea and imperforate hymen - best explanation?
The vaginal plate which arises from sinovaginal bulbs, undergoes canalization during embryonic development. Failure of canalization results in persistent
vaginal plate and thus imperforate hymen.
289
What are the two parts of the lesser omentum?
Hepatogastric (clear) and hepatoduodenum (with portal triad).
290
What is the omental bursa - or lesser sac?
A hollow space that is formed by the greater and lesser omentum and its adjacent organs. It communicates with the greater sac via the epiploic foramen of winslow, which is known as the general cavity of the abdomen that sits within the peritoneum, but outside the lesser sac. It is tricky because it is behind the hepaduodenal ligametn - door takes you to other space.
291
Where is the transpyloric plane?
midway between jugular notch and pubic - near L1
292
How does the neural plate divide? Does dorsal somatic (parietal) mesoderm lie under or over the ectoderm?
Each plate splits horizontally into the dorsal somatic (parietal) mesoderm, which underlies the ectoderm, and the ventral splanchnic (visceral) mesoderm, which overlies the endoderm.
293
What arteries lie within the gastrosplenic ligament?
short gastric and left gastroepiploic vessels.
294
What arteries lie within splenorenal ligament - "high yield"?
Splenic vessels as well as the tail of the pancreas
295
Is the phrenicosplenic ligament part of the greater omentum and where does it lie?
Yes, and between DPH and spleen
296
Is the greater sac divided into two portions?
Yes, the supracolic and suprahepatic - divided by transverse colon and transverse mesocolon.
297
What is a route of infection between pelvic cavity and upper abdominal region?
Right paracolic sulcus (gutter). Lateral to ascending colon. Communicates between hepatorenal recess and pelvic cavity.
298
Where does greater omentum come from embryonically?
Dorsal mesentery hanging down from stomach once stomach has turned 90 degrees and the Ventral mesentery becomes the lesser omentum.
299
In lesser omentum between liver and stomach, where are the left and right gastric arteries found?
Hepatogastric ligament. Hepatoduodenal has the portal triad.
300
In a surgery involving the liver - where would surgeon clamp to stop blood from flowing into liver?
Hepatoduodenal ligament - portal triad.
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Where do you access the lesser sac from the greater sac?
The free margin of the hepatoduodenal ligament. The epiploic foramen or Foramen of Winslow.
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Is the lesser sac the lesser bursa or the lesser omentum?
The Lesser Sac is the Lesser Bursa.
303
What is the ligament of teres?
The round ligament of the liver (or ligamentum teres, or ligamentum teres hepatis) is the remnant of the umbilical vein that exists in the free edge of the falciform ligament of the liver. The round ligament divides the left part of the liver into medial and lateral sections... and runs all the way down to the umbilicus
??
304
What is the gastrocolic ligament and what arteries does it contain?
The apron of the abdomen (Greater Omentum) - a four layer structure (because of flopping and folding) dorsal to stomach - with stomach and transverse colon attached. The gastroepiplatic vessels are found here - which feed the greater omentum and stomach
305
Where is the gastrosplenic ligament?
in the Greater Omentum - from stomach to spleen.
306
Does the splenorenal ligament have a part of the pancreas?
Yes, the tail, as well as the splenic artery and vein.
307
Where is the juncture between the foregut and midgut?
In the duodenum, just below the major duodenal papilla. Originally where liver bud sprouted, where bile duct comes into duodenum. The second part, or descending part, of the duodenum begins at the superior duodenal flexure. ... The second part of the duodenum also contains the minor duodenal papilla, the entrance for the accessory pancreatic duct.
308
Where is the vitelline duct located?
Communication between the intestinal loop and yolk sac.
309
What is the blood supply to the midgut?
Superior Mesentery Artery.
310
How many degrees does the midgut rotate - and where are the rotations done?
270 degrees - 90 degrees out side of body, 180 degrees when back in body.
311
Is the duedenum retro or intraperiotneal?
Both - first and 4th part intra - 2 and 3 - retro.
312
What is the blood supply of the 3rd part of duodenum?
Superior Mesentery artery - vs first parts of duodenum coming from Celiac via gastroduodenal artery
313
What's the duodenal cap?
The first part of the duodenum contains the duodenal cap or duodenal ampulla is the very first part of the duodenum which is slightly dilated. It is the part which is intraperitoneal and is about 2 cm long. It is mobile and has a mesentery. It is also smooth walled.
314
What is the ligament of Treitz? Where do you see it and what does it do?
??
Where the 4th part of duodenum ends and the jejunum begins. upper vs. lower GI bleed.
It allows space for the rotation of the intestinal loop among other things. In ER work - this may define what kind of injury you have based upon what is seen in your blood - digestive blood means the injury is distal to this ligament. ??
It is also thought to help digestion by widening the angle of the duodenojejunal flexure.
Gastrointestinal bleeding can fall into two broad categories: upper and lower sources of bleeding. The anatomic landmark that separates upper and lower bleeds is the ligament of Treitz, also known as the suspensory ligament of the duodenum
315
in the midgut, does the cranial or caudal part of the intestine grow more?
The cranial - and becomes a LOT of the small intestines - the caudal end develops less length, and becomes much of the large intestine - ending at the 2/3 line of transverse colon.
316
What happens if loop doesn't go back into body?
Oomphalocele. Has amnion. Probably chromosomal problem, w/ other problems - high mortality rate.
317
Gastrioschisis - is caused by what?
Failure of abdominal wall to close - no amnion involved. Less chromosomal issues, more association with younger mothers - not high mortality rate but dries out,
unprotected organs. Today 90% children survive.
318
What is a fistula of the vitalline duct and why does that happen?
Meckel's diverticulum at the ileum. Failure of vitalline duct to obliterate.
In the human embryo, the vitelline duct, also known as the vitellointestinal duct, the yolk stalk, the omphaloenteric duct, or the omphalomesenteric duct, is a long narrow tube that joins the yolk sac to the midgut lumen of the developing fetus
319
How is a volvulus created?
The vitelline vessels remnant that connects the diverticulum to the umbilicus may form a fibrous or twisting band (volvulus), trapping the small intestine and causing obstruction.
320
Is the anus part of the hindgut?
Only the first two thirds. The distal one third is ectodermal.
321
How does the cloaca develop?
it is split up into separate tracts during the development of the urinary and reproductive organs.
322
What is the allontois?
The allantois is derived from splanchnopleure (endoderm and splanchnic mesoderm). It arises as a diverticulum of the hindgut and gradually fills the entire extraembryonic coelom (exocoelom).
323
What happens to the allontois?
The embryonic allantois becomes the fetal urachus, which connects the fetal bladder (developed from cloaca) to the yolk sac. The urachus removes nitrogenous waste from the fetal bladder.
324
What is the urachus?
The urachus is a fibrous remnant of the allantois, a canal that drains the urinary bladder of the fetus that joins and runs within the umbilical cord. The fibrous remnant lies in the space of Retzius, between the transverse fascia anteriorly and the peritoneum posteriorly.
325
What is a patent urachus?
Patent urachus repair is surgery to fix a bladder defect. In an open (or patent) urachus, there is an opening between the bladder and the belly button (navel). The urachus is a tube between the bladder and the belly button that is present before birth.
326
What is the analrectul septum?
The endodermal cloaca is divided into a dorsal and a ventral part by means of a partition, the urorectal septum, which grows downward from the ridge separating the allantois from the cloacal opening of the intestine and ultimately fuses with the cloacal membrane and divides it into an anal and a urogenital part.
327
What is the dentate line?
The pectinate line (dentate line) is a line which divides the upper two thirds and lower third of the anal canal. Developmentally, this line represents the hindgut-proctodeum junction.
328
Does the anal pit recanalize?
YES, as does the hindgut - and they meet and form the dentate line. Both can have atresias - blind pounces - and not connect.
329
Anal canal (first 1/3) is ectoderm - stratified squamou - not part of the hindgut. What are the nerves?
There can be pain - inferior rectal a branch of the pudendal nerve - there is voluntary control. Upper 2/3 of anal canal is NOT painful - parasympathetic (pelvic splanchnic) /sympathetic (contracts - not defecate). Re PAIN - no pain, so can tell where the cancer, etc is. Different blood supplies as well.
330
mnuemonic for anal sphinter - voluntary control
S 2, 3, 4, keeps poo off the floor. Muscle around sphincter is the external anal sphincter.
331
What is a key difference about above and below the pectinate line?
PAIN - pain can be felt on the outside of the body and the first 1/2 of anal canal.
332
Blood supply re pectinate line?
Above (inside) -superior rectal artery - branch of inferior mesenteric. Below (near outside of body) Inferior rectal artery from internal iliac artery.
333
Re venous - possible hemeroids because above pectinate line - there is what venous drainage?
Superior rectal vein to inferior mesenteric to splenic vein to the portal vein to the liver. - Any liver problem can back up here.
334
Where does the internal iliac vein drain?
Inferior Vena Cava.
335
Where do the middle and inferior rectal veins drain?
into the Internal Iliac vein - at any rate into the systemic circulation - bypassing the liver.
336
What type of cells is mesentary made of?
Double layers, Simple squamous epithelial w/ mesothelial (basement membrane of aerolar connective tissue) - good to carry arteries, veins, nerves, lymphatic vessles.
337
Does the liver develop in the ventral or dorsal mesentery?
Ventral. And it will become the Lesser Omentum with associated ligaments.
338
What does the dorsal mesogastrium (mesentery) form?
Greater Omentum with many ligaments.
339
Where does the epiploic foramen lead?
Into the lesser sac.
340
What organ hangs from the cecum?
The Appendix with it's mesentery, the mesoappendix.
341
what mesentary, if any, anchors the jejunem and ilium?
Small bowel mesentery.
342
is the cecum intraperitoneal?
sometimes - it varies
343
Does the transverse colon have a mesentery?
Yes - the transverse mesocolon - for all of its structure.
344
How are cells differentiated in gut tube?
Specification is initiated by a concentration gradient of retinoic acid (RA) causing specific transcription factors to be expressed in different regions of the gut tube
345
What does HOX gene do in gut tube differentiation?
A lot. Hox genes specify regions of the body plan of an embryo along the head-tail axis of animals. Hox proteins encode and specify the characteristics of 'position', ensuring that the correct structures form in the correct places of the body.
Important for major sphincters, GI tract, etc
346
What does Sonic HH gene do in muscles?
High SHH concentration directly inhibits smooth muscle differentiation (via repression of Smooth Muscle Activating Protein, or Smap)
Low SHH concentration is permissive of muscle differentiation in the outer wall of the gut
The SHH gene provides instructions for making a protein called Sonic Hedgehog. This protein functions as a chemical signal that is essential for embryonic development. Sonic Hedgehog plays a role in cell growth, cell specialization, and the normal shaping (patterning) of the body.
347
Where is the ventral mesentery derived from?
The septum transversum which divide further into the lesser omentum and falciform ligament.
348
Is the dorsal mesentery responsible for the following structures?
```
YES:
Dorsal mesogastrium (greater omentum)
```
mesoduodenum
mesocolon
jejunal and ileal loops forms the mesentery proper
349
What does the falciform ligament contain?
The umbilical vein which is obliterated after birth.
Where is the round ligament?
to form the round ligament of the liver (ligamentum teres hepatis)
In anatomy, the round ligament of (the) liver (also commonly known by its Latin name, ligamentum teres - or more specifically ligamentum teres hepatis) is a degenerative string of tissue that exists in the free edge of the falciform ligament of the liver.
350
What roof does the Lesser omentum form?
the roof of the epiploic foramen of Winslow (Omental Foramen)
351
Is esophogael stenosis caused by failure to recanalize?
Probably yes. Postnatally, the child will regurgitate IMMEDIATELY upon feeding. However, there is usually NO tracheoesophageal fistula, so the lungs will usually NOT be congested - no pneumonia.
352
What is a congenital hiatal hernia?
When the esophagus fails to grow long enough so it pulls the cardiac stomach up into the esophogeal hiatus. Because the structure is compromised, other organs may come up too.
353
What is a DPH hernia?
90% are posterolateral Bochdalek hernias
Posterolateral defects of the diaphragm- usually on the left side. Morgani is in the sternocostal area - almost all right sides - high mortality rate due to pulmonary hypoplasia.
354
Failure of what gene signaling can lead to pyloric stenosis and what can one often see?
OLIVE often seen. Caudal end of the stomach is separated from the duodenum by formation of the pyloric sphincter (this process is dependent on factors such as SOX-9, NKX-2.5, and BMP-4 signaling). Most common to see 2 weeks - 2 months of life.
forceful or "projectile," non-bilious vomiting shortly after feeding (usually ~1 hour) because the hypertrophic sphincter prevents gastric emptying into the duodenum.
runs in families, more males
Not a recanalization error
355
Which vagus nerve supplies the anterior stomach?
left. Right is posterior
356
What is Diverticulum of the cecum
A rare, benign, generally asymptomatic lesion that manifests itself only following inflammatory or hemorrhagic complications. Most patients with inflammation of a solitary diverticulum of the cecum present with abdominal pain that is indistinguishable from acute appendicitis
357
What is the most common clinical manifestation of midgut malformation?
Neonatal intestinal obstruction
358
Why does midgut malformation occur?
Variety of reasons - lots of actions going on, easy to have happen.
359
What are some typical midgut malformations?
Agenesis:
Complete absence of an intestinal segment (incompatible with survival if it is very extensive)
Atresia and stenosis:
An intestinal segment is, and remains, narrow and constricted (obstructs the passage of food)
Seen most often in the ileum
Duodenal (intestinal) atresia:
Distal to the duodenal papilla; vomitus always has bile
Polyhydramnios may occur with duodenal atresia
Cause often failure of recanalization or interruption of the blood supply
Aplasia:
Where the contracted segment does have a mucosa and lumen
360
Duodenal atresia can also be a sign of what?
Intestinal obstruction may also be due to midgut volvulus or annular pancreas
361
What's the double bubble associated with?
Duodenal atresia - with Day 1 of life - bilious vomiting. Associated with Downs.
Supine radiograph of the abdomen demonstrates a dilated stomach and an accompanying dilated proximal duodenum.
362
What is volvulus?
Twisted intestine - surgery - Ladd's procedure. bilious vomiting, abdominal distension, hemodynamic instability (abnormal or unstable blood pressure, which can cause inadequate blood flow to your child's organs)
Often w/ associated problems - heart disease, , DPH hernia, Omphalocele
363
What are duplications in midgut malformation?
All duplications are caused by failure of normal recanalization and formation of two lumina
Range from simple diverticulae to almost complete doubling of the digestive tube
Also may include many varieties of cystic malformations
Commonly found on the dorsal (mesenteric) border of the intestine
364
Are gastroschisis and omphalocele ventral or dorsal body wall defects?
Ventral body wall defects:
Gastroschisis - 1 case in 2000 births
Omphalocele - 1 case in 4000 births
365
What are other types of Vental body wall defects?
Ectopia cordis, bladder exstrophy, and cloacal exstrophy, which are extremely rare
Bladder exstrophy - 1 case in 40,000 births
Ectopia cordis - 1 case in 125,000 births
Cloacal exstrophy - 1 case in 200,000 births
366
What is nonrotation re midgut malformations?
Nonrotation:
Quite common; called "left-sided colon" and generally is asymptomatic, but twisting or volvulus can occur
Midgut does not rotate after it enters the abdomen. Thus, the caudal limb enters before the cranial limb
Small intestine lies on the right side and the entire large intestine on the left.
May cause obstruction of vessels and gut if kinking or twisting occurs
367
Midgut malformation - due to failure of midgut loop to complete final 90 degrees - what happens?
Volvulus and mixed rotation:
Cecum lies below the pylorus and is fixed to the posterior abdominal wall by peritoneal bands (Ladd’s Bands) that cross over the duodenum
Usually causes duodenal obstruction
368
What causes malrotation of the small intestine?
Failure of normal sequence of rotation and fixation of the bowel.
369
What can malrotation of the small intestine lead to?
Duodenal obstruction can occur due to extrinsic compression from bands leading from the caecum to the lateral abdominal wall (Ladd’s bands) or from small bowel volvulus, which also leads to ischemia of the midgut from superior mesenteric artery occlusion
Midgut volvulus can lead to irreversible intestinal necrosis, which is potentially fatal
370
What are symptoms of bowel obstruction?
Bilious emisis (vomiting) in the neonate is an indication of malrotation until proven otherwise and is usually due to acute volvulus
Chronic volvulus will involve recurrent abdominal pain and malabsorption, as well as diarrhea, constipation, and gastroesophageal reflux.
Acute duodenal obstruction occurs mainly in infants and involves the compression of the duodenum by Ladd’s bands. Patients demonstrate forceful emesis.
Chronic duodenal obstruction may appear in older children (preschool-age).
Other less common presentations can include failure to thrive, solid food intolerance, malabsorption, chronic diarrhea
371
What is Ladd's procedure?
The procedure involves counterclockwise detorsion of the bowel,
surgical division of Ladd's bands,
the small intestine is placed on the right side of the abdomen, and the colon is placed on the left side.
372
Is omphalocele or gastroschisis a more serious problem? What's the mneumonic?
omphalocele - often because of chromosomal abnormalities, other problems, often associated with older mother. OMP - The abdominal contents are sealed in the O;, the Guts are coming out of the G.
373
What is an imperforate hymen and how is it formed?
A congenital disorder where a hymen without an opening completely obstructs the vagina. It is caused by a failure of the hymen to perforate during fetal development. It is most often diagnosed in adolescent girls when menstrual blood accumulates in the vagina and sometimes also in the uterus.
374
What embryonic structure gives rise to Gartner duct cyst?
Often appearing in lateral walls of vagina, these are remnants of mesonephric (woffffian) duct. Persistence of this duct can lead to Gartner cysts, and epoophoron and paroophone cysts. The paranephricducts are responsible for formation of the uterus, cervix and uppermost aspect of the vagina.
375
What is Potter's syndrome? 2 day old with acute respiratory distress, w/ anuria, oligohydramnios and hypoplast lungs.
Rare autosomal recessive trait associated with renal agenesis or hypoplasia. Presents with altered facial characteristics. Absense or lack of proper developemtn of kidneys causes oligohydramnios (too little amnionic fluid)
376
Two ureters on one side - how?
Note ureter pain, kidney stone - pain in lower back to pubic region. An early splitting of the ureteric bud results in formation of a second ureter on ipsilateral side. Failure of bud to form would cause complete absence of ureter. Normal is failure of ureteric bud to branch - causing one ureter joined to each kidney..
The urorectal septum is a section of tissue between the allantois and hindgut.
A persistent urachus acts as an abnormal fistula that runs from bladder to umbilicus, with urine leaking from external abnormal wall.
377
During surgery- where would fluid most likely gather with supine patient - in abdomen?
Morrison's pouch. The vesicouterine and rectouuterine pouches would provide predictable sites when patient is upright.``
378
with upright chest xray, air pocket noticed in abdomen - where most likely to gather?
The right subphrenic spaces is located between the inferior aspect of the DPH and superior surface of the liver. An ulceration in the posterior stomach wall would allow the passage of air from the stomach into this space through an open communication in the omental bursa.
379
ruptured cyst on left ovary, where is fluid likely to gather when patient supine?
Pouch of Douglas because it is the lowest point in the pelvis when patient is standing erect.
380
Thrombus in intestinal artery supplying the ileum, which layers of peritoneum will have to be entered by surgeon to gain access?
Parietal peritonium and the mesentery. One could reflect the greater omentum, but unlikely to need to pierce it.
381
multiple stones in gallbladder, shoulder pain - what nerves are associated?
T 5 - 9. Referred pain from gallbladder often in inferior angle of the right scapula.
382
right hepatic artery accidentally injured during gallbladder operation - to slow blood flow, what should be clamped?
Pringle manuever, NOT clampling the portal triad. The Pringle maneuver (total inflow occlusion) is performed by inserting the index finger through the foramen of Winslow and the thumb through a defect in the gastrohepatic ligament. An atraumatic clamp or Silastic vessel loop can be placed and tightened around the porta hepatis.
383
Severe abdominal pain, chronic colonic diverticulitis w/ massive bleeding (tachycardia and hypotension) - which artery is hemorrhaging?
Left colic artery. Given Answer choices, the only colon mentioned was the descending colon - hence the left colic.
384
What's the porta hepatis?
The porta hepatis or transverse fissure of the liver is a short but deep fissure, about 5 cm long, extending transversely beneath the left portion of the right lobe of the liver, nearer its posterior surface than its anterior border.
385
Which test helps confirm gallstones?
Murphy's sign - pressing deeply under right costal margin and asking patient to breath deeply. Causes sharp pain if cholecystitis.
386
gunshot, source of bleeding is a vessel within lesser sac, which ligament needs to be transected to gain entry to lesser sac?
Gastrocolic ligament which extends from greater curvature of stomach to transverse colon. The lowest point of the lesser sac occurs at intersection of gastrocolic ligament and trasnverse colon. bleeding would travel to the lowest point of lesser sace.
387
abnormal mass below pectinate line - adenocarcinoma - which lymph nodes would first received lymph from this area?
Superficial inguinal nodes. Anal canal primarily drains to these. The inferior rectum above the pectinate line drains into the internal iliac.The superior aspect of the rectum drains into the middle rectal lymph. The external iliac nodes primarily drain lower limb, pelvic and deep peritoneal structures. Deep inguinal lymph drains glands of clitoris and penis and superficial inguinal nodes.
388
same q as above, but above pectinate line?
Internal iliac.
389
What landmark distinguishes a sliding from a paraesophageal hiatal hernia? ??
In sliding hernias - the gastroesophageal juncture is displaced. In para - the stomach goes up along side of the esophagus - and is in danger of being twisted.
390
intense abdominal pain - xray reveals right subphrenic abscess extending to midline - what structure could retard spread of abscess across midline?
falciform.
391
football player, intense pain in back fracture of 11th rib on left - what organ?
The KIDNEY lies at the 12th rib and problems with respiration would result
392
painless mass on right groin, lymph biopsy reveal malignant cells - what is most likely primary source of carcinoma?
Anal canal drains into inguinal lymph nodes - specifically the superficial lymph.
393
massive tumor originating from third part of duodunum, which structure may be compressed or invaded by tumor?
Superior mesenteric artery.
394
What structure crosses the ureter just lateral to the cervix of the uterus?
Uterine artery lateral to the cervix.
395
What part of the brain will have Purkinje neurons?
Cerebellum, marked by many dendrites.
396
Where is CSF made?
Choroid plexus
397
What are the cells of cajal and betz?
Cerebral cortex - top lateral - cells of cajal (? -diiferent or same than the ones found in muscles?) - parallel to cortex, axons and dendrites; Betz - 5th layer (of 6), large pyramidal.
398
What are "nuclei" found in brain, and what are they?
in brain - islands of grey matter within white matter - aggregates of neronal cell bodies
399
What are nuerologlial processes?
A physical barrier - separates cortex from CSF.
400
What three things form the BBB? blood brain barrier
The blood-brain barrier is formed by endothelial cells of the capillary wall, astrocyte end-feet ensheathing the capillary, and pericytes embedded in the capillary basement membrane. per google/
per class - Arachnoid CSF Barrier; blood, CSF barrier; tight junctions.
401
What is the arachnoid CSF barrier?
The CSF-filled cisterns and spaces outside the brain are lined with arachnoid and pia cells. The arachnoid barrier consists of the arachnoid epithelium (mostly pia) which additionally intervenes, separating blood vessels from the subarachnoid CSF and brain.
402
What types of blood will a epidural, subarachnoid, and subdural hematoma have?
Epi and sub - arterial; subdural - venous.
403
Describe different brain layers involved in three types of hematomas.
?
404
What are Ependymal cells?
A specialized type of epithelial cells that line the ventricular system of the brain and play a key role in the production of cerebrospinal fluid.
405
How is CSF reabsorbed?
From the fourth ventricle it passes through three small openings (foramina) into the subarachnoid space surrounding the brain and spinal cord. CSF is absorbed through blood vessels over the surface of the brain back into the bloodstream. Some absorption also occurs through the lymphatic system.
subarach villi?
406
Where is CSF produced?
CSF is produced mainly by a structure called the choroid plexus in the lateral, third and fourth ventricles. CSF flows from the lateral ventricle to the third ventricle through the interventricular foramen (also called the foramen of Monro).
407
What's the flow of CSF
CSF flows from the lateral ventricle to the third ventricle through the interventricular foramen (also called the foramen of Monro). The third ventricle and fourth ventricle are connected to each other by the cerebral aqueduct (also called the Aqueduct of Sylvius)
408
What is the structure of the meninges?
The three meninges are the dura mater, the arachnoid mater, and the pia mater. The last two comprise the leptomeninges.
409
What are the arachnoid villi
Arachnoid granulations, or arachnoid villi, are small projections of the arachnoid membrane into the superior sagittal sinus and its major tributaries, involved in the absorption process of cerebrospinal fluid (CSF).
410
Problems of midgut formation:
Acute midgut volvulus.
Chronic midgut volvulus.
Acute duodenal obstruction.
Chronic duodenal obstruction.
Short bowel syndrome, in cases of volvulus with intestinal necrosis.
Death, in cases of volvulus with pan-necrosis of the bowel, severe septic shock or hypovolemic shock.
Malabsorption.
the small intestine found predominantly on the right side of the abdomen
the cecum displaced from its usual position in the right lower quadrant into the epigastrium or right hypochondrium
an absent or displaced ligament of Treitz - fibrous peritoneal bands called bands of Ladd running across the vertical portion of the duodenum
an unusually narrow, stalk-like mesentery
411
What is main cause of duodenal ulcer?
Infection with bacteria called Helicobacter pylori, or H. pylori. The bacteria can cause the lining of your duodenum to become inflamed and an ulcer can form. Some medications can also cause a duodenal ulcer, particularly anti-inflammatory drugs such as ibuprofen and aspirin.
412
What can cause duodenal obstruction?
It can occur due to myriad of causes from benign to malignant. The most common etiologies that present as intraluminal obstruction are bezoars and duodenal hematomas, whereas postbulbar peptic ulcer disease, duodenal tuberculosis, and Crohn's disease may present as luminal pathology like a stricture or stenosis.
413
What are the patches in the ?
Peyer patches, an important part of gut associated lymphoid tissue usually found in the lowest portion of the small intestine, mainly in the distal jejunum and the ileum, but also could be detected in the duodenum.
414
Where are the perkinje cells in the brain and how are they noted?
Cerebellum, LOTS of dendrites
415
What is the main function of the "little brain" - cerebellum?
Equilibrium (eye and head movement and balancing); Postural changes/muscle tone- smooth execution of voluntary movements (accuracy, perfection, control.
416
Three parts of brainstem:
midbrain (vision, hearing eye movement), pons (motor, sensory analysis) medulla oblongate (breathing and heartrate)
417
Where is grey matter in CNS and PNS
CNS - outside and deep inside - PNE - in the H
418
Islands of grey matter in white CNS is called?
Nuclei
419
IN the white matter, how do the mylineated axons arrange themselves?
Into Tracts - usually w/ particular function
420
What is a key component in the six layers of the cerebral cortex?
Pyramidal shaped neurons in various sizes.
421
What layer are the cells of cajal found?
top layer - running parallel
422
What layer are Betz cells, and what is their unique features
huge pyramid cells in 5th layer
423
How many layers does the cerebellum have
3 - outer molecular, purkinje cells (dendrites occupying most of this) , inner granular
424
What is the subarachnoid space?
layer in arachnoid - where CSF runs - this area communicates with ventricals of brain. It is a cavernous, columnar structure where blood vessels run and is bathed in CSF.
425
Does the arachnoid proper have blood vessels?
no, it touches the dura - via a protective membrane, and has no vessels - only the lower subarachnoid space has vessels
426
What are the nueroglial processes?
A thin layer between the pia matter and the cortex - forming part of BBB
427
What are the perivascular spaces?
Blood vessels penetrating the cortex via the subarachnoid space and pia matter, and neuroglial processes -
the capillaries are completely covered by neuroglial processes - the pia matter disappears before the blood vessels are changed into capillaries
428
How is CSF formed?
90% in choroid plexus - fenestrated endothelial capillaries take an ultrafiltrated plasma from blood capillaries, turn into excretory product - CSF
429
What are ependymal cells?
Ependymal cell, type of neuronal support cell (neuroglia) that forms the epithelial lining of the ventricles (cavities) in the brain and the central canal of the spinal cord.
They can secrete and absorb CSF - and are part of the BBB
430
What are the main components of the BBB?
Capillary endothelium, tight junctions, basal membrane and astrocyte feet.
431
What are where is the choroid plexus
3 and 4 ventricle, walls of 1 and 2 - specialized tissue projecting elaborate folds with many villi - - ependymal lining directly contacts pia mater.
432
Where does excess CSF drain?
from arachnoid villi to superior sagital sinus.
433
Where is the cerebral aqueduct
Between ventricles 3 and 4.
434
What is the main job of the choroid plexus?
Remove water from blood and turn into CSF. Each villus of choroid plexus contains a vascularized plexus of pia mater.
435
What is CSF made from?
CSF) is produced from arterial blood by the choroid plexuses of the lateral and fourth ventricles by a combined process of diffusion, pinocytosis and active transfer. A small amount is also produced by ependymal cells. ... The volume of the ventricles is about 25 ml.
436
What does excessive CSF cause? and When is it seen?
hydrocephalus - causing ventricular dilation - only rarely due to overproduction (tumor) - generally failure to absorb or obstruction.
In infancy prior to sutures closing - enlargement of head - in adults - expansion of the ventricles causing increased intracranial pressure - does not increase head size.
437
What is the venous sinus in the brain?
A layer near outside (skull, endosteum, venous) where arachnoid villi protude - where CSF is absorbed. the venous sinus collect oxygen depleted blood.
438
What are the sinuses of the brain?
The dural venous sinuses (also called dural sinuses, cerebral sinuses, or cranial sinuses) are venous channels found between the endosteal and meningeal layers of dura mater in the brain.
439
What are the different types of hematomas in brain?
subdural hematoma, intraparenchymal hemorrhage (from contusion), and subarachnoid blood. Subdural hematomas are recognized by their crescent shape overlying and compressing the brain.
Epidural hematomas are usually caused by bleeding from the middle meningeal artery, while subdural hematomas are usually due to bleeding from veins that drain blood away from the surface of the brain. ... This makes subdural hematomas more deadly.
440
Are sheath of Schwann and sheath of myelin the same?
No. Both will be present in myelinated PNS axons - unmyelinated will only usually have schwann layer
441
What is the neurlolemma?
Sheath of schwann - a thin cell layer - of schwann cytoplams - Schwann have heterochromatic nucleus, lots of mitochondria, micro filatments, lysosomes, RER and Golfi
442
How is thickness of myelin determined?
in PNS, myelin wraps around up to 50 layers - depends on diameter of axon, signaled by neuregulin (Nrg1) - growth factor.
443
Do Schwann cells completely cover mylieneated axons?
Sometimes several Schwann will be needed to cover mylineation - and there are gaps - Nodes of Ranvier - important for nerve impulse transmission - one schwann for each internode -
444
In some places, does the Schwann loosen up?
Yes. Schmidt Lantermann clefts or incisures are thought to be where the Schwann loosens
445
is myelin same in CNS and PNS?
No, different composition, but similar percentage - -
both have MBP and P2-
only protein Zero and PMP22 in PNS (created by Schwann)
PLO only in CNA
446
Function of the nodes of Ranvier?
Gaps in the myelin sheath coating on the neural axon. The myelin allows the electrical impulse to move quickly down the axon. The nodes of Ranvier allow for ions to diffuse in and out of the neuron, propagating the electrical signal down the axon.
Nodes of Ranvier are microscopic gaps found within myelinated axons. Their function is to speed up propagation of action potentials along the axon via saltatory conduction. ... The Schwann cells of the myelin sheath block the movement of sodium ions elsewhere along the axon
447
Does myelination enhance conductivity
Yes - the thicker the more conducive, the more energy conservation. The excitation is confined to nodal Ranvier regions.
448
describe the fiber type of nerve cells in skeletal muscles?
A alpha - 70 - 120 conduction velocity, diameter wide, mylienated.
449
if infant vomiting bile - what does that tell you?
problem is below the the ampulla of Vater, also known as the hepatopancreatic ampulla or the hepatopancreatic duct, is formed by the union of the pancreatic duct and the common bile duct. The ampulla is specifically located at the major duodenal papilla.
Usually found in 2nd duodenum.
450
If red currant jelly in stools?
Intussusception - telescoping of bowel.
451
if 270 degrees of perfection midgut rotation, where will the SMA be between?
Jejunum behind, and transverse column in front
452
What is a subhepatic secum?
Failure of last 90 degrees of rotation, cecum fails to descent.
453
What organ comes off of cecum?
Appendix (with mesentery)
454
What is a meckle's scan?
A Meckel's scan can help identify this abnormal tissue. Your child will receive something called Technetium-99m through a vein. This substance has a tiny amount of radioactive material in it. ... The camera will show if this material appears in a Meckel's diverticulum in your child's small intestine.
455
Meckle's diverticulum - how common? Cause?
VERY common - most common - 2%, rule of 2s - cause: remnant of yolk stalk - vitaline duct.
456
if gastric mucosa seen in relation to meckle's during tech scan
You may have a meckle's diverticulum even without other symptoms.
457
What causes blood in stool and abdominal pain?
Bright red blood mixed with the stools indicates the bleeding is acute and likely in the colon. Causes include infections, IBD, diverticula, or tumor. ... Sometimes bleeding from the stomach can be so perfuse that it appears as bright red blood from the rectum.
458
Why do some organs lose their mesenteries
They scoot back to the posterior wall, and don't need one.
459
how to locate the appendix?
Convergence of 3 bands on cecum - taenia coli
460
Where is the ileocecal valve and what does it do?
A sphincter muscle situated at the junction of the ileum (last portion of your small intestine) and the colon. Its function is to allow digested food materials to pass from the small intestine into your large intestine. It's normal position is closed.
461
What causes inflammation of the ileocecal valve?
Ileocecal thickening (ICT) is a common finding on radiological imaging. It can be caused by a variety of inflammatory, infectious, or neoplastic conditions, and evaluating a patient of ICT can be a challenging task. Intestinal tuberculosis (ITB), Crohn's disease (CD), and adenocarcinoma are the most common causes.
462
What part of the gut is the appendix?
Midgut
463
Where does the hindgut begin?
last 1/3 of transverse colon.
464
What is agenesis in midgut?
Partial lack of part of intestine.
465
Where is most common area for atresia, stenosis in midgut?
Ileum
466
Signs of atresia, stenosis in midgut?
Vomiting bile (defines location), polyhydramnios, due to recanalization - or interruption of blood supply.
467
What causes volvulus and clinical signs?
Twisting around - often a mesentery - mesentery too loose. Clinical signs? shock, abdominal distention
468
What is ladd's procedure?
Removal of mesentery and reorganization of midgut so no problems.
The procedure involves counterclockwise detorsion of the bowel, surgical division of Ladd's bands, widening of the small intestine's mesentery, performing an appendectomy, and reorientation of the small bowel on the right and the cecum and colon on the left (the appendectomy is performed so as not to be confused by ...
469
What is the cecal diverticulum in week 6?
Beginning of formation of appendix. The appendix is a vestige of incomplete cecum.
470
What is the major problem with malformations of midgut?
Neonatal intestinal obstruction - variety of causes - failed complete rotation, failure of fixation of mesenteries, other organ problems,
471
Intestinal obstruction - due to what?
Duod atresia, midgut volvulus, annular pancreas
472
When might you see the double bubble?
Duodenal atresia (gas in both stomach and duodenum) - associated with Downs
473
Volvulus - what is it, what will you see?
Twisted small intesting around mesentery - bilous vomiting, abdominal distention, blood instability -
Associated disorders
oomphacele, heart disease, DPH hernia
Remedy? Ladd's
474
What are duplications in midgut caused by?
failure of normal recanalization - usually dorsal mesentery problem.
475
Nonrotation midgut problems
left colon (possibly w/ volvulus) - caudal end re-entered first
476
What are Ladd's bands?
fibrous stalks of peritoneal tissue that attach the cecum to the retroperitoneum in the right lower quadrant (RLQ)
Usually the bands cause intestinal obstruction
477
Signs of malrotation in midgut?
```
Signs of bowel obstruction
Bilious emisis (vomiting) in the neonate is an indication of malrotation until proven otherwise and is usually due to acute volvulus
Chronic volvulus will involve recurrent abdominal pain and malabsorption, as well as diarrhea, constipation, and gastroesophageal reflux.
Acute duodenal obstruction occurs mainly in infants and involves the compression of the duodenum by Ladd’s bands. Patients demonstrate forceful emesis.
Chronic duodenal obstruction may appear in older children (preschool-age).
Other less common presentations can include failure to thrive, solid food intolerance, malabsorption, chronic diarrhea
```
478
By what week is oomphacele obvious?
10th. higher Mortality rate than gastroschisis
479
Intussusception signs
Target on xray - sausage shape, often meckels is lead point, red currant jelly - dark red stools, abd pain, usually in children. May be from virus - peyer patch hypertogphy creates lead point.
480
Malrotation of midgut
small bowel on right - formation of Ladd's bands - can lead to volvulus, deod obstruction
481
Hirschsprung disease?
Megacolon - Downs, explosive feces, lack of enteric nervous plxuses in distal colon - failure or neural crest cells to migrate.
failure to pass mecumium in 48 hours, chornic constipation. normal portion of colon proximal is dilated.
482
What is the source of slow waves in the gastrointestinal tract?
Cells of cajal.
483
What are the major vascular structures that pass underneath the inguinal ligament?
Femoral vessels (artery and vein)
484
What vessels supply the lesser curvature of the stomach?
Right and left gastric.
485
What segments of the small intestine have plicae circulares?
Distal duodenum, jejunum, and proximal ileum
486
Which epithelial glands are found throughout the small intestine?
Crypts of Lieberkühn
487
Why does a ruptured abdominal aorta present with back pain and not chest or epigastric pain?
The aorta in the abdomen is retroperitoneal, so pain is referred to the dorsal side of the body
488
The inferior epigastric vessels are branches of which vascular structures?
External iliac arteries and vein
489
What is Nutcracker syndrome?
compression of left renal vein between superior mesenteric artery and aorta. Characterized by abdominal (flank) pain and gross hematuria (from rupture of thin-walled renal varicosities).
490
Superior mesenteric artery syndrome?
characterized by intermittent intestinal obstruction symptoms (primarily postprandial pain) when SMA and aorta compress transverse (third) portion of duodenum. Typically occurs in conditions associated with diminished mesenteric fat (eg, low body weight/malnutrition).
491
What is the difference with arteries in GI system?
Arteries supplying GI structures are single and branch anteriorly.
Arteries supplying non-GI structures are paired and branch laterally and posteriorly.
492
What are the watershed regions re blood supply and abdomen?
Two areas of the colon have dual blood supply from distal arterial branches (“watershed regions”) susceptible in colonic ischemia:
Splenic flexure—SMA and IMA
Rectosigmoid junction—the last sigmoid arterial branch from the IMA and superior rectal artery
493
Where will peyer patches be found?
The ileum
494
What is primary lymph drainage below pectinate line?
Superficial inguinal nodes
495
What's the Pringle manuever?
Compression during surgery of portal triad via compression of the hepatoduodenal ligament
496
Digestive tract histology
Digestive tract histology
Esophagus
Nonkeratinized stratified squamous epithelium. Upper 1/3, striated muscle; middle and lower 2/3 smooth muscle, with some overlap at the transition.
Stomach
Gastric glands .
Small Intestine
A
Duodenum
Villi and microvilli absorptive surface. Brunner glands(HCO3−-secreting cells of submucosa) and crypts of Lieberkühn (contain stem cells that replace enterocytes/goblet cells and Paneth cells that secrete defensins, lysozyme, and TNF).
B
Jejunum
Villi, crypts of Lieberkühn, and plicae circulares (also present in distal duodenum) .
C
Ileum
Peyer patches lymphoid aggregates in lamina propria, submucosa), plicae circulares (proximal ileum), and crypts of Lieberkühn. Largest number of goblet cells in the small intestine.
D
Colon
Crypts of Lieberkühnwith abundant goblet cells, but no vill
497
What submucosal glands are unique to the duodenum?
Brunners
498
What are the functions of the pancreas?
exocrine, endocrine.
Exocrine:
Acinar (looks like cloud bubbles) secrete fluids to aid in digestion - including bicarbonate to neutralize stomach acids in duodenum. (alkiline) - secrete through Pancreatic main and accessory duct.
Endocrime: Islets of Langerhans
Also creates insulin and glucogone that regulate blood levels, and somotostatin which prevents release of both of above. Glucogone (makes glucose gone). Insulin ups glucose.
Mr. Gluca has Gone to the cAMP to bring out some Glucose
Insulin - insulin causes sugars in the blood stream to be transported into the cells, decreasing the blood sugar level.
insulin beta, glucogon alpha (vowel goes with consonant)
499
What arteries are near the pancreas (a lot) - which ones come from the hepatoduodenal?
The superior pancreaticoduodenal artery and inferior pancreaticoduodenal artery anastamose between the duodenum and the right lateral border
500
What vessels does the neck of the pancreas straddle?
Superior mesenteric and portal vein
Behind the pancreas - (Posteriorly), superior mesenteric and splenic vein confluence to form portal vein
501
Body of pancreas? what arteries?
Splenic vein runs embedded in the posterior surface
Inferior surface is covered by transverse mesocolon
502
Tell me about the tail of the pancreas.
it is intraperitoneal,
Lies at T12
Ends within the splenic hilum
Lies in the splenophrenic ligament
Anteriorly, related to splenic flexure of colon
May be injured during splenectomy (fistula)
503
Pancreatic cancer?
Very serious - often discovered too late - 80% are adenocarcinomas of the ductal epithelium.
anorexia, malaise, nausea, fatigue, and midepigastric or back pain
504
Pancreatic duct?
Main duct (Wirsung) runs the entire length of pancreas
Joins CBD at the ampulla of Vater
Ductal pressure high
lesser duct (santorini)
505
What is the duodenal papilla?
Where the converging ampulla of vater w/ pancreatic main duct enter 2nd duod -
sphincter of ODDI - controls the release of bile and pancreatic fluid into the duodenum.-
506
What does the sphincter of Oddi do?
controls the release of bile and pancreatic fluid into the duodenum.-
507
With gallstones, what do they often block?
The ampulla of vater. Depending upon patient - this may also block the pancreatic duct - cause reflux of bile into pancreas.
508
What is the main cause of pancreatitis?
having gallstones. Gallstones cause inflammation of your pancreas as stones pass through and get stuck in a bile or pancreatic duct.
509
Arteries to pancreas - so many
Anterior collateral arcade between the anterosuperior and anteroinferior
pancreaticoduodenal artery
Posterior collateral arcade between the posterosuperior and posteroinferior
pancreaticoduodenal artery
Body and tail supplied by splenic artery by about 10 branches
Three biggest branches are
Dorsal pancreatic artery
Pancreatica Magna (midportion of body)
Caudal pancreatic artery (tail)
510
Does the celiac or MSA supply the pancreas?
BOTH -
Celiac Common Hepatic Artery Gastroduodenal Artery Superior pancreaticoduodenal artery which divides into anterior and posterior branches
SMA Inferior pancreaticoduodenal artery which divides into anterior and posterior branches
511
Does pancreas ultimately drain into portal vein?
Yes.
512
Lymph drainage of pancreas?
rich - 5 nodes
```
Superior nodes
Anterior nodes
Inferior nodes
Posterior PD nodes
Splenic nodes
```
513
Nerves of pancreas?
Sympathetic -greater and lesser thoracic splanchnic nerves
Parasympathetic vagus
514
What does spleen do embryonically that it doesn't do at other times?
Creates blood (as does the liver).
515
Why is the spleen called the graveyard?
Because it takes out old RBCs. haemoglobin is dissociated into heme and globin
516
What are the ligaments of the spleen?
It is intraperitoneal - and from mesenchymal cells
at the hilum as the gastrosplenic ligament to the greater curvature of the stomach (carrying the short gastric and left gastroepiploic vessels)
Also passes to the left kidney as the splenicorenal ligament (carrying the splenic vessels and the tail of the pancreas)
517
Is the spleen associated with a bleeding tendency including purpura and petechiae?
Yes - Immune thrombocytopenic purpura (ITP) is a bleeding disorder in which the immune system destroys platelets, which are necessary for normal blood clotting. People with the disease have too few platelets in the blood.
518
What is pancreas divisum and is it dangerous?
common - two ducts fail to fuse from two buds (ventral rotating and joining with dorsal - and then... ducts joining (except for the accessory) - however
Pancreas divisum can lead to recurrent or acute pancreatitis, which is painful and can lead to malnutrition. It occurs when the narrow pancreatic duct becomes blocked as the digestive juices find it difficult to drain into the small intestine. This causes swelling and damage to the tissue
519
Nerves of PNS - from lecture June 3 - three coverings of nerves.
three covering of nerves - Endoneurium -> Peri-> Epi.
Endo (forms a tube around each axon); Peri around fasciculats - blood barrier; Epi around entire thing - ... it's EPIC
520
How does endoneurium effect neuron regeneration?
if endos tubes can remain intact - regeneration is enhanced. Endoneurium hugs tightly the axon (compressing it - creating a bit of pressure)
If axon degenerates, endo tube collapses by 80%.
They are loose connective tissue
521
What does perineurium do and what is it made from?
Wraps individual wrapped axons into fascicules -
Gives elasticity to nerve when stretched and creates blood nerve barrier for protection of toxins.
Contains Actin - and attached to others with TIGHT Junctions.
Thin but dense - 3 or four layers of flattened CT cells. of collagen fiber.
522
EPInuerium (EPIC - around all!)
Wraps around whole nerve, CT dense fibrous irregular - cushioning nerve especially where nerve crosses joint - disappears as nerves become finer and finer.
EPI merges with adiopose tissue, etc has fibroblasts, mast cells and collagen bundles
523
Effect of injury on neuron? how many outcomes?
2 - die or regenerate -
524
What happens in nerve degeneration?
cell increases in size due to water coming in -
organelles disappear - Nissi, Golgi, nucleus moves to edge.
525
What is Wallerian Degeneration? Degeneration of...
AXON!
Myelin sheath breaks down into fat droplets, axoplasm disintegrates w/in 24 hours; endoneurium collapes; macrophages invade to clean up debris - Schwann may also contribute lytic enzymes.
526
What is the roll of Schwann cells in nerve regeneration?
KEY - have to have it.
They proliferate on both ends of stump, reinflating endoneurium tube, and bridging gap.
Axon starts growing from proximal end - using Schwann as tightrope lines to distal end (occasionally gets lost and grows sideways).
And in a perfect world - all goes back to normal - axon plumps up, myelin sheath reforms, axon terminal flourishes, nucleus back to center, etc.
527
If injury to nerve too severe or too distal, what happens regarding regeneration?
The nerve can't bridge the gap - so a nerve bundle forms at a dead end - neuroma - swelling - very sensitive - ie where limb no longer exists.
528
Autonomic Nervous system is made of what three groups? -
Sympathetic, para, and Enteric - controls smooth and cardiac muscles, and glands
529
Parasympathetic characteristics
relaxing - cervical C 3, 7, 9, 10? and sacral L 2 - 4; ACH Only, long presynaptic - often to organ. - always stimulatory
530
Sympathetic - two types of ganglia
Chain and collateral
Short presynaptic -
Also medulla can go to blood vessels - the synapse is a chemical into vessel -
Ach, Epin EP, Nore NE, Dopamine DO - and receptors - nicotinic, alpha 1,2, Beta, 12 M1,3,5, M2, 4
Can be excitory (stimulatory) or inhibitory
Neurons of the collateral ganglia, also called the prevertebral ganglia, receive input from the splanchnic nerves and innervate organs of the abdominal and pelvic region. These include the celiac ganglia, superior mesenteric ganglia, and inferior mesenteric ganglia.
531
Sensory vs Autonomic?
Sensory - skeletal muscles - Voluntary, ACH only, no post ganglionic - only one synapse - at the muscle with a nicotinic receptor.
532
Are postganglionic nerve fibers myelinated?
No. Sensory Axons are highly myelinated - and run all the way to the skeletal muscle.
533
Patient reporting red rectal blood - what can it be?
Hemorrhoids — Painless bleeding is usually associated with a bowel movement. Bright red blood typically coats the stool at the end of defecation. Blood may also drip into the toilet or stain toilet paper
Anal fissures — Anal fissures can usually be diagnosed from the history. Affected patients describe a tearing pain with the passage of bowel movements. The passage of stool may be accompanied by bright rectal bleeding usually limited to a small amount on the toilet paper or on the surface of stool. Some patients complain of an itch or perianal skin irritation
Polyps — Polyps, including adenomatous polyps, are generally asymptomatic and are most often detected by colon cancer screening tests. Small adenomas do not typically bleed, but occult bleeding and minimal BRBPR can occur; minimal BRBPR is more likely with distal polyps
Proctitis — Patients with proctitis or proctosigmoiditis often present insidiously with intermittent rectal bleeding associated with the passage of mucus, and mild diarrhea with fewer than four small loose stools per day
Rectal ulcers — Rectal ulcers can present with bleeding, passage of mucus, straining during defecation, and a sense of incomplete evacuation
Cancer — The majority of patients with symptomatic colorectal cancer have hematochezia, abdominal pain, and/or a change in bowel habits. Patients with minimal BRBPR from colorectal cancer are likely to have left-sided lesions.
534
What are some gallbladder anomolies?
Anatomic variants of the gallbladder are fairly common in which two, bilobed, diverticula, and septated gall bladders are found
Septated gallbladder is most likely due to incomplete recanalization of the lumen
535
What is extrahepatic Biliary Atresia?
Biliary atresia is characterized by obliteration or discontinuity of the extrahepatic biliary system, resulting in obstruction to bile flow
The disorder represents the most common surgically treatable cause of cholestasis encountered during the newborn period
If not surgically corrected, secondary biliary cirrhosis invariably results
536
What are the two types of biliary atresia?
Isolated - postnatal - 65-90%
Patients with associated situs inversus or polysplenia/asplenia with or without other congenital anomalies (fetal/embryonic form), comprising 10-35% of cases
537
Signs of neonatal biliary atresia?
Typical symptoms include variable degrees of jaundice, dark urine, and light stools
In the case of biliary atresia, most infants are full-term, although a higher incidence of low birthweight may be observed
In most cases, acholic stools are not noted at birth but develop over the first few weeks of life. Appetite, growth, and weight gain may be normal
538
What does biliary atresia look like in children?
Biliary Atresia Symptoms in Children
Pale or clay-colored (acholic) stools, an indication that very little or no bile (which gives bowel movements their normal color) is reaching the intestine. Enlarged liver that feels harder than normal, enlarged spleen. Poor weight gain.
539
Does liver or spleen make blood for the fetus? HEMATOPOIESES
Both - and generally end pre-birth.
540
Functions of liver?
Storage of energy sources (glycogen, fat, protein, and vitamins)
Production of cellular fuels (glucose, fatty acids, and ketoacids)
Production of plasma proteins and clotting factors
Metabolism of toxins and drugs
Modification of many hormones
Production of bile acids
Excretion of substances (bilirubin)
Storage of iron and many vitamins
Phagocytosis of foreign materials that enter the portal circulation from the bowel
541
What do hard nodes on a liver mean, when palpitating?
suggest malignancy. An obstructed distended gallbladder can also be felt -
542
What does very tender liver suggest?
Inflamation of congestion (congestive heart disease).
543
What are the lobes of the liver?
```
Right lobe (largest lobe)
Left lobe
Quadrate lobe (lies between the gallbladder and the round ligament of the liver)
Caudate lobe (lies between the IVC, ligamentum venosum, and porta hepatis)
```
544
How are livers segmented?
in 8 or so groups - different people have developed three different systems -
545
Is the common bile duct part of the portal triad?
Yes - and the proper hepatic and portal vein.
546
What vessels are connected to the liver?
Hepatic artery, portal vein, and hepatic veins.
547
Does the bile produced and sent out of the liver eventually return to the liver?
Yes, via the portal vein in the venous blood.
548
Does the liver create much lymph?
YES - half of the body's lymph. Celiac node and posterior mediastinal
549
What innervates the Liver
The celiac plexus and vagal trunk (giving rise to large hepatic branch).
550
Signs of liver disease?
Can be seen in head (spider angioma) constructional apraxia (can't draw star of David), bad breath - dead mouse (fetor hepaticus, jaundice, parotid gland enlargement.
CHEST - diminished hair, spider angioma, ,
HANDS
asterixis (tremor)
Palmar erythema (pale hands with red palms)
clubbing of fingers, Terry's nail (paleness at base) Duputryen's contracture (Fingers w/ palm)
551
What's shamroth's sign?
Looking for clubbing in fingers - nails can't touch when second knuckles put together
552
Other liver disease signs?
Scratch marks, petechiae, echymosis, edema, testicular atrophy, female escucheon in male - public hair shape reversed.
553
Bile passage from liver
from the left and right hepatic ducts, down the extrahepatic, into the CBD... if a stone is in the extrahepatic duct, and not yet in the CBD branch - will see gallbladder on contrasted film. If see neither gall or liver, stone is in CBD because contrast is reaching neither.
554
What stimulates bile from liver?
Vagus and CCK (produced in duodenum usually after fatty big meal).
555
Three functions of Sphincter of Oddi?
Regulation of bile and pancreatic flow into the duodenum
Diversion of hepatic bile into the gallbladder
The prevention of reflux of duodenal contents into the pancreaticobiliary tract
556
Does the gallbladder secrete bile?
The gallbladder stores and concentrates bile from the liver. The bile is then released into the first section of the small intestine (the duodenum), where it helps your body to break down and absorb fats from food. ... When we eat fatty foods, the gallbladder contracts and squeezes bile through the bile duct.
557
What is the Spiral valve of Heister?
The mucous membrane of the cystic duct is raised to form a spiral fold
558
What is the triangle of Calot?
Calot's triangle (cystohepatic triangle) is a small anatomical space in the abdomen. It is located at the porta hepatis of the liver – where the hepatic ducts and neurovascular structures enter/exit the liver.
559
Is there a danger associated with the triangle of Calot?
Small (potential) triangular space at the porta hepatis of surgical importance as it is dissected during cholecystectomy. Its contents, the cystic artery and cystic duct must be identified before ligation and division to avoid intra-operative injury.
560
Is porta hepatis the same as portal triad?
A wide array of pathologic conditions can arise within the porta hepatis, which encompasses the portal triad (the main portal vein, common hepatic artery, and common bile ducts), lymphatics, nerves, and connective tissue.
561
What cause the gallbladder to contract?
the hormone cholecystokinin (CCK), which is produced by the mucous membrane of the duodenum on the arrival of fatty food from the stomach
562
What is Cholelithiasis ?
Gallstone disease. Gallstones are concretions that form in the biliary tract, usually in the gallbladder
Gallstones develop insidiously, and they may remain asymptomatic for decades
563
what are gallstones made from - and can they be a mixed variety? Can they become infected?
80% US - cholesterol monohydrate crystal -
Can also be Calcium, bilirubin, and pigment gallstones BLACK in color due to oxidation
Yes to mixed and yes to infection.
564
What is biliary colic, and when does surgery need to happen?
Biliary colic occurs when gallstones impact in the cystic duct during a gallbladder contraction
In most cases, the pain resolves over 30 to 90 minutes. If not - need to operate.
Other symptoms, often associated with cholelithiasis, include indigestion, dyspepsia, belching, bloating, and fat intolerance
565
Where is referred pain in gallbladder
Right shoulder.
566
How are gallbladders removed - if there are stones? Can you have acute vs. chronic gallbladder problems?
It there are stones and pain, almost always need to remove gallbladder - Laparoscopic, entry through Carot's triangle - careful of nerves associated sometimes not where you think they should be - different percentages of where they will be.
Acute will show with dark circle around area in ultra sound
567
Complications to gallbladder surgery?
```
Gallbladder Empyema (pus)
Perforation
Gallbladder Adenocarcinoma
Cholecystoenteric fistula
Common bile duct obstruction
Ascending cholangitis (inflamation of bile duct)
Acute pancreatitis
```
568
Does the hepatic portal system drain all of the Abdominal GI system?
YES. and takes non-oxygenated, nutrient rich blood to liver.
569
What two veins form the Portal vein?
SMV and Splenic.
570
Liver cirrohsis?
Cirrhosis represents the final common histologic pathway for a wide variety of chronic liver diseases
Cirrhosis is defined histologically as a diffuse hepatic process characterized by fibrosis and the conversion of normal liver architecture into structurally abnormal nodules
The progression of liver injury to cirrhosis may occur over weeks to years
571
How much of the liver can grow back?
The liver is the only visceral organ that possesses the capacity to regenerate. The liver can regenerate after either surgical removal or after chemical injury. It is known that as little as 51% of the original liver mass can regenerate back to its full size
572
Etiology of cirrhosis?
Most common causes of cirrhosis in the United States
Hepatitis C (26%)
Alcoholic liver disease (21%)
Hepatitis C plus alcoholic liver disease (15%)
Cryptogenic causes (18%) - Many cases actually are due to NAFLD
Hepatitis B - May be coincident with hepatitis D (15%)
Miscellaneous (5%)
573
5 portal systemic anastomosis?
Naturally occurring venous communications between tributaries of the portal venous system and tributaries of the systemic venous system
The major portal-systemic anastomoses include:
Esophageal branches of left gastric vein with esophageal veins
Paraumbilical veins with subcutaneous veins of anterior abdominal wall
Superior rectal vein with middle and inferior rectal veins
Retroperitoneal veins with venous branches of veins of the colon and bare area of the liver
A patent ductus venosus connecting left branch of portal vein to inferior vena cava (rare)
574
What causes esophageal, rectal, and caput medusea varices?
Portal vein hypertensions.
Esoph - left gastric with azygos,
rectal - superior rectal vein w/ meddle and inferior rectal
Umbil - paraumbilical w/ superficial epigastric.
Patent ductus venosus (PDV) is an uncommon vascular malformation, classified as a type of intrahepatic shunt [1]. In utero, the ductus venosus connects the left portal vein to the inferior vena cava, allowing a portion of the venous blood to bypass the liver and return to the heart.
575
What's the Pringle manuver?
Clamping the hepatoduodenal ligament interrupting the flow of blood through the hepatic artery and the portal vein and thus helping to control bleeding from the liver
30 minutes, no longer
576
What are the retroperitoneal organs?
SAD PUCKER
Supradrenal, aorta and IVC, dudodemn (2 - 4), pancreas (except tail) ureters, colon (asc, dec) kidney, esoph (thoracic) Rectum (partially)
577
How deep do ulcers go?
SMS (of MSMS) - if it is only in the mucous layer - it is an EROSION
578
What's up with the band - Waves of Cajal?
Electric wave rhythm (slow) in interstitial cells of CAJAL - stomach, duo, ileum. Smooth muscles?
Interstitial cells of Cajal (ICC-IM) are involved in the stimulation of smooth muscle cells, neurotransmitters act through them.
579
What two areas of the colon have dual blood supplies?
Splenic flexure (SMA and IMA); Rectosignmoid Junction ( Last sigmoid of IMA and superior rectal a).
Both of these areas are subject to Colonic ischemia, also referred to as ischemic colitis, is a condition characterized by a reduction of blood flow to the colon (i.e., large bowel or large intestine).
580
What is nutcracker syndrome and where does it occur?
compression of left renal vein between SMA and Aorta .
581
What is Superior Mesenteric Artery Syndrome?
Characterized by intermittent intestinal obstruction syndrome ( when SMA and aorta compress transverse (third) portion of DUO. Often due to lack of body weight, fat - lack of mesenteric fat.
582
What are two strong anastomoses in celiac trunk area?
Left and right gastric; left and right gastroepiploics.
583
What are the three varices of Gut, butt, and caput?
from Portal vein problem - , esophoGUT, rectum, and umbilicus
584
What are the different lymphatics, arteries and veins involved in the Pectinate Line?
Above: Lymph - drain to internal iliac; Art: Superior rectal of IMA; superior rectal vein to IMV - splenic - portal vein.
Below: Lymph - Superficial Inguinal; Inferior rectal artery - branch of Internal pudendal; Inferior rectal vein - internal pudendal vein - internal iliac vein - common iliac vein - IVC
.
585
What can you tell me about Anal Fissures? Is it above or below the Pecinate Line?
Tear in anal mucosa below Pectinate Line, Pain while Pooping; blood on toilet Paper; Located Posteriorly because this area is Poorly Perfused - innervated by the Pudendal nerve.
586
What shape is liver tissue
6 sided, central vein, portal triads on the edge (portal vein, hepatic artery, bile and lymph too). Kuppfer cel ls (macrophages) in sinusoids - Blood runs in canals in and Lymph runs out in other canals.
587
What's the double duct sign re the pancreas?
Stones blocking both the CBD and Pancreatic duct - at the ampule of vater. Tumors can cause this in head of pancreas.
588
What does the mneumonic Ice Tea stand for?
Internal Spermatic fascia, Crematerie muscle and fascia; External spermatic fascia; Transverse fascia, Internal oblique, external oblique. spermatic cord layers
589
What's the liver's round ligament of remnant of?
The umbilical vein.
590
Posterior duodenal ulcer most commonly damages which artery?
Posterior superior pancreaticoduodenal artery.
591
An anterior perforating ulcer of the duodenum is most likely to cause what injury?
Peritonitis. Perforating ulcers pierce the duo or stomach anteriorly, penetrating ulcers posteriorly
592
What nerve complex innervates the ureters?
sympathetic and parasympathetic ureter plexus. visceral afferent will be at T11 - L2 for the sympathetic.
593
What ligament is typically used as a landmark for surgeons in the duo/jejunum area?
The ligament of Treitz at the 4th duo.The superior and inferior mesa arteries and the vasa recta are too variable in location to be used as landmarks.
594
IN a baby, what can cause herniation of abdominal organs into thorax with a posterolateral defect in the DPH?
Failure of pleuroperitonial folds to close. Defective formation of the pleuroperitoneal membranes and/or their failure to fuse with the dorsal mesentery of the esophagus and the septum transversum results in a congenital posterolateral defect of the diaphragm. This means that the intestines pass into the thorax, sometimes accompanied by the stomach and spleen.
If it was failure of muscles to develop in dPH, would have paradoxical respiration
Failure of the septum transversum to develop would cause absense of central tendone and is not normally associated with congenital dDPH hernia.
595
Are Morgagni hernias often between the costal margin and ziphoid process?
yes. and if severe can cause respiratory distress Bochdalek are not near the ziphoid but is due to a posterolateral hernia..
596
What organ can become ischemia when arterial supply from SMA is compromised?
The Ileum. The SMA arises from aorta posterior to neck of pancreas.
597
What anamostis is first affected by portal hypertension?
The umbilicul veins.
598
What would common bile duct compression result in?
Jaundice and increased seum bilirubin.
599
What would compression of the common bile duct lead to?
An inflamed gallbladder (cholecystitis).
600
What is a dermatome?
An area of skin supplied by a single spinal nerve.
601
Where does the descending column receive its visceral sensory nerve supply for pain from?
SC L1, L2.
602
What do the nerves from L1 to Lr supply?
Rectum, bladder and uterus.
603
What is a gallstone ilius?
This occurs when a gallstone ulcerates through the wall of the body of the gallbladder and into the duod. Pain can mimic appendicitis. Bowel sounds will be exaggerated above the obstruction and absent distal to the obstruction.
604
What are the Veins of Retzius?
are various veins in the dorsal wall of the abdomen forming anastomoses between the inferior vena cava and the superior and inferior mesenteric veins. ... More rarely, anastomosis may occur with the left gonadal vein via a venous network developed from the inferior mesenteric vein
605
What symptoms would appear if the ampulla of vater was obstructed?
jaundice and radiating pain localized into right upper quadrant with referred pain to scapula.
606
What artery supplies blood to the lowest part of the esophagus below the dph?
Left gastric artery. Perforation in this area, could easily injure this artery. The inferior phrenic supplies the portion of the EPH just superior to the DPH.
607
What is Kerh sign?
Ruptured spleen -w/ intense radiating pain to top of left shoulder.
608
What is the most common variation in hepatic artery supply to the right lobe of the liver?
Right hepatic artery originating from the SMA.
609
if catheter not entering gallbladder - what may be blocking it?
Spiral valve of Heister (which is a fold of skin, and is not actually a valve but it is tortuous.
610
Is the dPH affected by autonomic nerves?
No, it is a skeletal muscle and it innervated by somatic nerve fibers in the phrenic nerves. So if there was some mutation to autonomic nerves the DPH would not be affected.
611
I Slow Red Ox ?
Skeletal muscles - three types, slow and fast (and intermediate), white and red,
Type 1, slow, red, for marathons, lots of myoglobin
612
Muscle types can change, and how are they different?
Red can become white, and vice versa via a change of innervation - so if it is red, and the innervation is stopped and a white innervation is then connected - ti becomes white.
- Red and white vary bec of myoglobin (protein similar to hemoglobin, binds o2), number of mitochondria, enzymes, rate of contraction.
613
Red and white skeletal muscles - ATPase difference?
Red - low in ATPase,
What does an ATPase do?
ATPase. ATPases are enzymes that catalyze the hydrolysis of adenosine triphosphate (ATP) into adenosine diphosphate (ADP) and a free phosphate ion. This reaction leads to the release of energy which is used in the cell.
White high and high in phospholorases. Because white muscles don't have as many mechanisms to obtain and use oxygen to generate energy, they rely on anaerobic (oxygen-less) energy generation. As a result, the fast twitch fibers are sometimes called anaerobic fibers. The energy generated by anaerobic mechanisms relies on sugar.
Red - They have large amount of mitochondria whereas, the white muscle fibres have low amount of mitochondria and myoglobin. ... Red muscle fibres have slow conduction due ti low myosin ATPase activity whereas, white muscle fibres have fast conduction due to high myosin ATPase activity.
614
Basic structure of skeletal muscle?
Packaged with Endo (forming aponuerosis to tendons), peri, and EPImyocin
Sarcoplasma, multi nucleated, striated (meaning... sarcoplasma with z discs, M, H,line, I band, A band (A band ALWAYS stays the same) during contraction.
Myofibrils of different proteins form thick and thin filament
Calcium gated (no leaky gates like cardiac and smooth), when depolarized, T tubules invaginations pull out ryan stoppers and release Ca+ from T tubule cisterns - TRIAD.
615
What is the thin filament in skeletal muscle?
made of Nebullin, Actin (G to F), Troponin (3), and Tropomyocin which blocks active sites.
616
What is Titan?
Recoils the sarcomere like a spring after it is stretched.
Stabilize the thick filament, center it between the thin filaments
617
What does C protein do in skeletal muscles?
M LINE _ Myosin-Binding protein-C (MyBP-C) is a family of accessory proteins of striated muscles that contributes to the assembly and stabilization of thick filaments, and regulates the formation of actomyosin cross-bridges, via direct interactions with both thick myosin and thin actin filaments.
618
How is ATP used in skeletal muscles?
ATP binds to myosin, moving the myosin to its high-energy state, releasing the myosin head from the actin active site. ATP can then attach to myosin, which allows the cross-bridge cycle to start again; further muscle contraction can occur.
619
What is the dihydropyridine receptor? DHPR
DHPR plucks the ryanodine receptor out of the Sarc Ret - thus allowing Ca+ to be released.
The dihydropyridine receptor (DHPR), normally a voltage-dependent calcium channel, functions in skeletal muscle essentially as a voltage sensor, triggering intracellular calcium release for excitation-contraction coupling
620
How does the ryanodine receptor work?
Ryanodine receptors mediate the release of calcium ions from the sarcoplasmic reticulum and endoplasmic reticulum, an essential step in muscle contraction. ... However, as the concentration of intracellular Ca2+ rises, this can trigger closing of RyR, preventing the total depletion of SR.
621
Describe how a neuron causes contraction in a skeletal muscle?
1. Message coming down axon.
Axon terminal at rest is negative. Sodium is positive and circulating outside wanting to come in, as is Calcium
2. Message opens sodium gated voltage channels - and sodium rushes in. Depolarizing wave occurs.
3. Calcium voltage gated channels open when reach threshhold (+ 30 MV threshold when gate opens) - the Calcium is used to eventually will bind SNARES to pull vesicle to membrane edge - thus allowing release of ACH). The cell is now becoming more positive.
2. Choline enters cell via diet/GI system, and meets up with Acetyl-Coa from Mitochondria. ACH is created using special enzyme.
3. ACH climbs into vesicle via 2dary messenger action from proteins going into vesicle via ATP, and then when too many proteins in vesicle, they come out allowing ACH in.
5. Calcium that had come in early Snares the snare proteins which pull vesicle to membrane, and Ach is released into cleft
6. Ach binds to receptor on awaiting muscle at nicotinic or musculatore receptors allowing
??sodium to flood in. When enough sodium in, calcium channels open ????
ACH high in t terminals, sodium lower in.
7. ? Ach allows opening of Ca+ channels - which begin depolarization
8. when wave reaches T tubules, DPHR plucks Ryan out of Cisterne - and Ca+ floods into muscle (sequested by calsequester)
9. Ca+ goes to sarcomere - where binds to tropinin C, white opens active sites on actin thin filament,
10. permitting myocin heads to bind into thin filament from thick, causing pulling and contraction.
622
What is an alpha vs gamma motor neuron?
motor neurons whose cell bodies are found in the anterior horn of the spinal cord and whose axons travel down to the body to innervate skeletal muscle to cause muscle contraction.
Gamma motor neuron are the efferent (sending signals away from the central nervous system) part of the fusimotor system, whereas muscle spindles are the afferent part, as they send signals relaying information from muscles toward the spinal cord and brain.
Alpha motor neurons control muscle contraction involved in voluntary movement, whereas gamma motor neurons control muscle contraction in response to external forces acting on the muscle. In response to these external forces, the gamma motor neurons induce the involuntary, reflexive movement called the stretch reflex.
623
Where are vesicles for Ach made?
Made in cell body in spinal cord in anterior horn, moved down axon via kinesin.
624
Where are all neurotransmitters of protein made?
In Neuron cell bodies.
625
Where is ACH made?
In the preganglionic terminal bulbs. It is NOT a protein -
626
What do choline and acetate make? and where do they come from?
Choline (from your diet and thus your GI tract) and there are channels on the terminal bulb to allow choline in.
Mitochondria - has acetalchoa - (basis for kreb's cycle), i
627
What is ACH made of?
it is an ester of acetic acid and choline. Parts in the body that use or are affected by acetylcholine are referred to as cholinergic.
Acetylcholine is synthesized in certain neurons by the enzyme choline acetyltransferase from the compounds choline and acetyl-CoA. Cholinergic neurons are capable of producing ACh
628
What is Acetyl-CoA , and where does it come from?
is a molecule that participates in many biochemical reactions in protein, carbohydrate and lipid metabolism. Its main function is to deliver the acetyl group to the citric acid cycle to be oxidized for energy production.
It comes from mitochondria
629
How is ACh made?
from choline from diet, and Acetyl-Coa merge - Coa is released - energy needed to make this happen is the enzyme Cholineacytal transferase.
630
Ach is made in the terminal bulb, how do we get it into a vesicle?
ATP used to make this happen. ATP breaks to ADP and inorganic phosphate. Proteins move into vesicle. when High enough concentration in vesicle, move out of vescicle, they help ACH come in via secondary transport
631
What do v and t snares do and where are they?
V snares (synatotagnin and synaptobrevin) are attached to vesicles - T snares (Snap 25 and syntaxin) are bound to cell membrane. They snare each other - and pull the vesicle to the membrane.
Calcium CROSSLINKS these proteins - that were at rest without Calcium.
Calcium links these snares together, thus causing release of ATP.
632
What is the order of muscle contraction in a skeletal muscle?
1. ACH leaves terminal bulb and binds with receptors
2. depolarizes postsynaptic sarcolemma
3. Propagation of T tubules affecting DPHA and RYAN plucked from Sarcoplasmic Reticulum
4. Release of Ca+ from Sar Ret
5. Binds with troponin C and affects confirmation change in troponin tropomyocin complex (allowing myocin heads to contact with thin filament and begin contraction)
633
What causes Muscular dystrophy?
Dystrophin mutation - truncated or absent - waddling gate, - connects the cytoskeleton to ECM. Duchenne - onset before 5 years old; Becker (Becker is Better)
X linked disorder
Patients typically present with muscular complaints affecting specific muscle groups, particularly the pelvic girdle musculatur
634
What's an intercalated disc, and where is it found?
CARDIAC muscle cells, unique junctions called intercalated discs (gap junctions + desmesome) link the cells together and define their borders. Intercalated discs are the major portal for cardiac cell-to-cell communication, which is required for coordinated muscle contraction and maintenance of circulation
635
how is 85% of the body's heat produced?
Skeletal Muscles
636
Where are satellite cells found in muscles and what do they do?
These are active during repair and regeneration.
Satellite cells are able to differentiate and fuse to augment existing muscle fibers and to form new fibers. These cells represent the oldest known adult stem cell niche, and are involved in the normal growth of muscle, as well as regeneration following injury or disease
637
How are muscles attached to bones, cartilage or ligaments?
Tendons and aponeurosis
638
What does epimyseium, perimyseium and endomysium do?
Wraps muscles EPIC - is the last layer, then peri wraps fascicles, and endo (delicate layer) the individual cell fibers.
639
Where do the arteries, veins and nerves run in a muscle?
2 arteries, one vein and nerve through CT, with capillary system piercing each endomysium.
640
What does a skeletal muscle cell contain?
muscle cell or fiber (sarcoplasm) made of microfibrils, nucleuses, sarcolemma, satellite cell and wrapped in endomysium.
large, multinucleated, nuclei on surface, external to sarcolemma is glycoproteins and fine network of retic fiber forming external lamina that binds with adjacent muscle cells.
641
Why are they called "striated" muscles?
You can see the striping, caused by overlapping thin actin and thick myosin filaments that together make up myofibrils
642
What are skeletal muscles? and what does syncitia mean?
Multinucleal post-mitotic structures where nucleus has lost ability to synthesize DNA. Once myofibers are developed from uninuclear myoblasts, which come to form myotubes, and then mature myofibers (from mesoderm)- in fetus, muscles can not duplicate. syncitiza means several cells have now formed into one.
643
What is the formula for a sarcomere?
1/2 I + A + 1/2 I
644
What is the H band
space between two thin filaments in sarcomere.
645
What are red fibers vs. White fibers?
Red - 1 slow red ox. Red meat, white meat! and then Intermediate.
646
Do white or red have more mitochondria?
Red. They also have more myoglobin (oxygen binding sites).
647
What is the main protein in the M line?
Creatine kinase.
CK stands for creatine kinase, an enzyme that leaks out of damaged muscle. When elevated CK levels are found in a blood sample, it usually means muscle is being destroyed by some abnormal process, such as a muscular dystrophy or inflammation
648
What does creatine kinase do at the M line?
Replenishes ATP during muscle contraction.
M-line-bound creatine kinase is a back up source of energy when ATP is low in muscles. Seems to have the capacity for the intramyofibrillar regeneration of most or all of the ATP hydrolyzed by the myofibrillar ATPase during muscle contraction
649
What are the four main proteins in a myofibril?
myosin, actin - together are 55%, tropomyosin, troponin.
650
What do Thin filaments have?
Thin filaments have nebullin, G Actin (f -actin) tropomyosin BLOCKS, tropinin groups (tnt, tnc tnI
651
What do the myocin head do?
plug into the active sites in the thin filament which causes contraction.
652
What proteins does the Z line contain?
desmin and alpha-actinin.
653
What regulated the elasticity of the sarcomere and limits its displacement range when stretched?
Titan
654
What do costameres do in the muscle and how do they work with Desmin?
Desmin, an intermediate filament, extends from one myofibril to the other, and anchors to the sarcolemma - desmin inserts into costameres which are specialized attachment regions of the sarcolemma. Plectin and ab-crystallin play a roll too.
655
What does alpha-actinin do in skeletal muscles?
anchors the barbed end of actin filaments to the Z disk
656
where are the Transverse tubules found in a muscle cell?
Area of overlaps between A and I bands. Each sarcomere has two of these tubules
657
What are the swollen sacs of the sarcoplasmic reticulum called?
Terminal cisternae. Making a triad in skeletal muscles ( a diad in cardiac)
658
How are the cisternae attached to the t tubules and what accumulates in them during rest??
Gap Junctions - Ca+ accumulates via calsequester
659
How many sarcomere are in a muscle cell?
A muscle fiber from a biceps muscle may contain 100,000 sarcomeres. The myofibrils of smooth muscle cells are not arranged into sarcomeres
660
Where would myoglobin be higher? Red or White cells?
Red fibers are more resistant to fatigue than are white fibers. Red fibers have more myoglobin (oxygen binding pigment) than white fibers. White fibers store glycogen and use anaerobic metabolism. Red fiber and slow twitch muscle is for endurance.
661
White cells - FAST - don't use oxygen, but glucose, for action - so do they have more or less myoglobin?
LESS - RED=myoglobin
662
At the top of a T tubule, what can be bound?
? ACh receptors vs. sodium?
663
What is the primary function of the sarcoplamsic reticulum?
To store calcium
664
What is muscular dystrophy?
A group of diseases - characterized by mutation in the dystrophin gene... which links the muscle fibers to the cytoskeleton and ECM. Loss of the DAP complex
665
What does dystrophin do, and where does it lie?
Dystrophin is a protein found in muscle cells. It is one of a group of proteins that work together to strengthen muscle fibers and protect them from injury as muscles contract and relax. It links muscles to the cytoskeleton and ECM. it links to Laminan 2 and others
666
What do dieretics do? and how does that affect muscles?
Diuretics, sometimes called water pills, help rid your body of salt (sodium) and water. Most of them help your kidneys release more sodium into your urine. The sodium takes with it water from your blood, decreasing the amount of fluid flowing through your veins and arteries. This reduces blood pressure.
667
How does smooth muscle control blood flow?
Vascular smooth muscle contracts or relaxes to change both the volume of blood vessels and the local blood pressure, a mechanism that is responsible for the redistribution of the blood within the body to areas where it is needed (i.e. areas with temporarily enhanced oxygen consumption)
668
How does smooth muscle help control blood pressure?
The main function of vascular smooth muscle tone is to regulate the caliber of the blood vessels in the body. Excessive vasoconstriction leads to high blood pressure, while excessive vasodilation as in shock leads to low blood pressure
669
What is myathenias gravis?
POST synaptic - a rare chronic autoimmune disease marked by muscular weakness without atrophy, and caused by a defect in the action of acetylcholine at neuromuscular junctions.
Receptors on MUSCLE for ACH are blocked - can't bind, can't repolarize,
670
What is lambert eaton myathemic syndrome?
PRESYNAPTIC - Calcium channels on terminal bulb are blocked - so vesicles can't snare it up.
autoimmune disease — The attack occurs at the connection between nerve and muscle (the neuromuscular junction) and interferes with the ability of nerve cells to send signals to muscle cells
671
What is the difference between myasthenia gravis and Lambert Eaton syndrome?
Post vs. Pre -
Histologically - POST (muscle receptors for ACH are blocked) so cell can not depolarize and muscle can not receive calcium.
PRE - Calcium channels are blocked on the terminal - so can't snare it up so no ACH is delivered to cleft.
The difference between LEMS and myasthenia gravis (MG)
This is very similar to myasthenia gravis, however the target of the attack is different in MG as the acetylcholine receptor on the nerve is affected, whereas in LEMS it's the voltage-gated calcium channel on the nerve
672
How does myasthemia Gravis present?
Facial muscles - drooping eyelids, double vision - muscles not working - if gets to DPH - hard to breathe! Now better survival re ventilators, etc.
Drugs - steroids, Cholinesterase - (inhibits ?
673
Can some antibiotics adversely effect Calcium channel response in neuron terminals?
YES - and if calcium channel is blocked, no calcium, no snare action, no ACH, no muscle movement
674
What does botulinis toxin do in muscles?
Snare complex not form. Vesicles of ACH can't deliver.
675
What is malignant hypothermia?
Excessive release of Ca+ from Sarc Retic. Chrom 19, mutated channels open too easily, rigid muscles - too much Ca+ stimulating glycogen, glycolosis, aerobic matabolsim, Excessive HEAT Production - whole muscle breaks down. CAUSED by drugs
676
Is malignant hypothermia related to phamacology?
yes.
677
What do myasthenia gravis and Lambert_Eaton myasthnic syndrome have in common?
They are both autsomsal neuromuscular junction diseases. MG more common (POST), worsens w/ muscle use; facial, eyes, difficult to chew - where it starts; associate w/ thymoma/thymic hyperplasia. - Drugs can have some beneficial affect
Lambert - PRE - starts in Limbs, improves with muscle use, associates w/ cell lung cancer
678
What are the 2 types of cholinergic receptors?
Acetylcholine receptors (AChRs) are of two types: muscarinic (mAChR) and nicotinic (nAChR) based on the agonist activities of the natural alkaloids, muscarine and nicotine, respectively. These receptors are functionally different
679
What is malignant hyperthermia?
Malignant hyperthermia (MH) is a disease that causes a fast rise in body temperature and severe muscle contractions when someone with MH gets general anesthesia. MH is passed down through families. Hyperthermia means high body temperature
680
What is the botulinum toxin, and how does it affect muscles?
Binds presynaptically to Calcium channels - SNARE problem so ACH can not be released.
681
How does rigor mortis affect muscle contraction?
The muscles remain in the contracted state until adenosine triphosphate (ATP) binds to myosin, releasing the myosin and actin filaments from one another. ... Unable to release contraction, all the muscles of the body remain tense, causing rigor mortis.
682
What causes rigor mortis?
A stiffening of muscles fibers after death, resulting from the flood of calcium ions into the sarcomere (contractile units of the muscle fiber).
683
If there is too much calcium in muscles, what happens
Rigor mortis (not really), because that happens once you are dead - but the muscles don't relax - you need ATP to make the muscles relax. So too much calcium, w/o enough ATP is a problem.
684
What receptor does botulinum toxin bind?
Botulinum toxin, one of the most lethal biologic toxins, is produced by the bacteria Clostridium botulinum. It acts at the neuromuscular junction, where it binds to the presynaptic cholinergic terminal and inhibits the release of acetylcholine. This functional denervation causes weakness and atrophy
685
What triggers motor neurone disease?
There are many theories, including exposure to environmental toxins and chemicals, infection by viral agents, immune mediated damage, premature ageing of motor neurones, and loss of growth factors required to maintain motor neurone survival and genetic susceptibility. Most cases of MND occur spontaneously
686
To stimulate a muscle, where does the action need to begin, and where does it reach the muscle fiber(s)?
In the ventral horns of the spinal cord - each nerve fiber can stimulate 3 to many muscle fibers - each neuromuscular junction meets the muscle fiber near the midpoint. 98% muscles have only one junction
687
What is the motor end plate?
Above the synaptic cleft. Nerve fibers can form complex branching that lie outside of fiber plasma membrane. Perisynatpic Schwann cells insulate at preganglionic terminal.
Acetylcholine is synthesized in cytoplasm terminal and absorbed into small synaptic vesicles (~ 300,000 or more in terminal of single endplate)
688
is ATP needed to synthesize ACH?
Indirectly, to get the ACH into the vesicles you need ATP (which is true), whether you need before that - I don't know
689
What happens if acetylcholine receptors are blocked?
Cobras and Curare
The acetylcholine receptor is an essential link between the brain and the muscles, so it is a sensitive location for attack. Many organisms make poisons that block the acetylcholine receptor, causing paralysis
690
What receptor does botulinum toxin bind?
Botulinum toxin, one of the most lethal biologic toxins, is produced by the bacteria Clostridium botulinum. It acts at the neuromuscular junction, where it binds to the presynaptic cholinergic terminal and inhibits the release of acetylcholine. This functional denervation causes weakness and atrophy
691
What does Acetylcholinesterase
| do?
This enzyme breaks down ACH in synaptic cleft
692
What are subneural clefts?
invaginations at the motor endplate - which have synatpic cleft - In the Cleft there is a lot of Actylchoinesterase to break down ACh once it has done it's job.
Subneural clefts increase surface area of synaptic membrane.
ACH
ACh gated channels at top
Voltage gated Na+ channels in bottom half
693
What are dense bars in the presynaptic terminal bulb?
Ca2+ channels are localized around linear structures on the pre-synaptic membrane called dense bars
Vesicles fuse with the membrane in the region of the dense bars.
Ach receptors located at top of subneural cleft.
Voltage gated Na+ channels in bottom half of subneural cleft
694
How does end plate potential work?
ACh released into the neuromuscular junction binds to, and opens, nicotinic ACh receptor channels on the muscle fiber membranes (Na+, K+, Ca2+).
Opening of nACh receptor channels produces an end plate potential, which will normally initiate an AP if the local spread of current is sufficient to open voltage sodium channels.
What terminates the process?
Acetylcholinesterase
695
What's the sliding interdigitating filament hypothesis?
During muscle contraction -
sarcomeres shorten, Z lines move close, I bands become less prominent - A Band ALWAYS stays the same. Sliding occurs as thin filaments come together causing greater overlap
696
At the T-tubule triad, what are the two proteins of import?
Dihydrophyridine (voltage sensor) plucks RYANODINE out of the cisternae of the sarcoplamic reticulum.
697
How does Ca+ get back into the cisternae?
Ca2+ ATPase - The pump is found in the membrane of the sarcoplasmic reticulum. ... Powered by ATP, it pumps calcium ions back into the sarcoplasmic reticulum, reducing the calcium level around the actin and myosin filaments and allowing the muscle to relax.
698
inside the cisternae, with what does Ca+ bind to facilitate storage?
Calsequestrin.
699
What does Cathepsin K do?
It is a proteinase that is secreted by osteoclasts and results in bone degradation, primarily of type I collagen.
it is also produced by cancer cells that metastasize to bone.
700
What does RANK and calcitonin do in bones?
RANK facilitates osteoclast bone degradation, calcitonin slows down osteoclast activity
Specifically RANK is the interaction between osteoblasts and preosteoclasts that tells macrophages to transform under low blood CA and high pth levels?
701
How does a contraction end?
The Ca+ breaks its connection with Troponin C and accumulates again the cisternae
702
What does too much Ca+ or lack of ATP create in muscles?
A type of tetany, muscle rigidity, as Calcium can not detach. ATP is needed for detachment. Like Rigor mortis similar
703
Do osteoclasts have PTH receptors?
No, the have RANK receptors, and calcitonin receptors. RANK increases their activity (of bone destruction) and Calcitonin slows them down.
704
What causes Calcium to release the myocin head in muscle contractions?
ATP - without it - bad news.
705
During muscle contractions, does the thin filament get shorter?
No, nor does the A Band. It does however overlap
706
What is OPG in bone?
Osteoprotegerin (OPG) DECOY? is secreted by osteoblasts and osteogenic stromal stem cells and protects the skeleton from excessive bone resorption by binding to RANKL and preventing it from interacting with RANK. The RANKL/OPG ratio in bone marrow is thus an important determinant of bone mass in normal and disease states.
707
Where is calcitonin produced?
Calcitonin is a 32 amino acid hormone secreted by the C-cells of the thyroid gland.
708
What is Rhabdomyolysisit?
is the breakdown of damaged skeletal muscle. Muscle breakdown causes the release of myoglobin into the bloodstream. Myoglobin is the protein that stores oxygen in your muscles. If you have too much myoglobin in your blood, and can cause kidney damage
709
What cause malignant hyperthermia?
A dose of anesthetics. The reaction is sometimes fatal. It is caused by a rare, inherited muscle abnormality. Infrequently, extreme exercise or heat stroke can trigger malignant hyperthermia in someone with the muscle abnormality
710
How do skeletal muscles vary the force of the contraction, as if one is firing, it is all or nothing?
Muscles are broken up into motor units, and different amounts of these fire - depending upon the circumstance.
One motor unit can fire many muscle fibers or a few. Fine motor skills use small motor units.
711
How is fine control done, such as in the eye, with motor units?
Each nerve fiber innervates one muscle fiber
712
What does it mean when myasthenic gravis syndrome may cause ptosis and diplopia?
eye lid drooping and double vision. More females are harmed by this autoimmunie disease. Treatment - anticholiesterase agents (which encourage ACH), steroids, and thymectomy
713
What causes myasthenic gravis?
autoimmunity - POST synaptic - ACH can't bind. symptoms increase with activity
714
What does blue sclera associate with?
osteogenesis imperfecta / type I collagen mutations
715
Can some types of antibiotics have a significant neuromuscular effect?
Yes, cipro, etc can block Ca+ gates opening in presynaptic neurons.
716
If Traf6 or Nfatc1 is defective what result would that have on bones
Overproduction or no production of osteoclasts.
these are the genes that signal to macrophages to create osteoclasts.
Specifically if it doesn't work you would get NO osteoclasts, if it works to well, TOO many osteoclasts
This is related to RANK
717
Is there autonomic disfunction with MG and LEMS?
Only with LEMS. and with LEMS - you likely won't see diplopia and dysphagia - and weakness IMPROVES with activity. LEMS is rarer
718
Botulinus Toxin? what does it do?
Blocks ACH presynaptic ca+ receptors
719
Are there drugs that can help with this botulinum toxin?
two kinds - one type that can not be reversed -
tubcararine, etc - a NON-DEPOLARIZING med
that competitively blocks nACH receptors - (a receptor antagonist). The effects of these drugs can be reversed by Anticholiesterase drugs that increase the ACH with synaptic cleft.
Succinylchoines is a depolarizing drug . it is a receptor agonist - competing with ACH for receptor. it maintains an open sodium channel - eventually causing skeletal muscle relaxation and paralysis - Can not be reversed. May cause Malignant Hypothermia.
720
What is a receptor antagonist?
A type of receptor ligand or drug that blocks or dampens a biological response by binding to and blocking a receptor rather than activating it like an agonist. STOP THE BIND
721
What is a receptor agonist?
An agonist is a chemical that binds to a receptor and activates the receptor to produce a biological response. An agonist CAUSES an ACTION, an antagonist blocks the action of the agonist, and an inverse agonist causes an action opposite to that of the agonist. BINDS INSTEAD OF WHAT WAS SUPPOSED TO
722
What is malignant hyperthermia?
Gene mutation on chromosome 19 - for the ryanodine receptor - OPENS channel more easily - cell is flooded with Calcium - causing muscle contraction (rigidity), also stimulates glycogen, glycoysis and aerobic matabolism causing Excessive Heat production.
Body creates more and more ATP to get rid of calcium, body heats up, and stores of glycogen are used up. Also stimulates lysosome action, nuclear DNases, potentaill resulting in rhamdomylosis.
This is brought on by being administered a certain drug
723
What is rhabdomyolysis?
A breakdown of damaged skeletal muscle. Muscle breakdown causes the release of myoglobin into the bloodstream. Myoglobin is the protein that stores oxygen in your muscles. If you have too much myoglobin in your blood, it can cause kidney damage
724
What controls tension in muscles?
Muscle Spindles - enclosed in fluid filled space, numerous where fine motor control is needed (eg eye, hand)
made of smaller muscles called interfusal fibers (normal skeletral called extrafusal)
725
What are intrafusal fibers?
Intrafusal muscle fibers are skeletal muscle fibers that serve as specialized sensory organs (proprioceptors) that detect the amount and rate of change in length of a muscle. They constitute the muscle spindle and are innervated by both sensory (afferent) and motor (efferent) fibers
726
What is the neuromuscular spindle?
Only in SKELETAL MUSCLES _ A spindle-shaped end organ in skeletal muscle in which afferent nerve fibers terminate and which is sensitive to passive stretching of the muscle enclosing it
727
What is a muscle spindle and how does it work?
Loading the muscle spindle: When activated the muscle spindle causes the muscle being stretched to generate tension to resist the stretch, so by stretching a muscle immediately prior to a contraction you effectively prime the muscle to create more force for that contraction.
728
What's a Golgi Tendon Organ?
Golgi tendon organs (GTOs) are receptors that are activated by stretch or active contraction of a muscle and that transmit information about muscle tension.
The Golgi Tendon Organ is a proprioceptive receptor that is located within the tendons found on each end of a muscle. It responds to increased muscle tension or contraction as exerted on the tendon, by inhibiting further muscle contraction. ... Golgi tendon organs are arranged in series with the extrafusal muscle fibers.
729
What's the difference between a nuclear chain and bag fiber?
A nuclear chain fiber is a specialized sensory organ contained within a muscle. Nuclear chain fibers are intrafusal fibers that, along with nuclear bag fibers, make up the muscle spindle responsible for the detection of changes in muscle length. ... They are static, whereas the nuclear bag fibers are dynamic in comparison
A nuclear bag fiber is a type of intrafusal muscle fiber that lies in the center of a muscle spindle. Each has many nuclei concentrated in bags and they cause excitation of both the primary and secondary nerve fibers. There are two kinds of bag fibers based upon contraction speed and motor innervation.
730
To whom does the muscle spindle communicate
To the CNS via afferent nerve fibers reporting status of muscles
731
What are muscle spindles and Golgi tendon organs?
Unlike muscle spindles (located in parallel with muscle fibres), Golgi tendon organs are located in tendons near the myotendinous junction and are in series, that is, attached end to end, with extrafusal muscle fibers. Golgi tendon organs are activated when the tendon attached to an active muscle is stretched.
732
What is the difference between Golgi tendon organs and muscle spindles?
Golgi tendon organs are activated when the tendon attached to an active muscle is stretched. ... The result is a reduction in tension within the muscle and tendon. Thus, whereas spindles facilitate activation of the muscle, neural input from GTOs inhibits muscle activation
733
What is an alpha motor neuron
Stimulates skeletal muscles
734
What is a gamma motor neuron?
involved in reflexes and involved in adjusting muscle tension in spindles
735
How do golgi tendons work?
near insertion of muscle fiber in tendons, CT sheath encapsulates several large bundles of collagen.
Sensory nerves penetrate the capsule,
They detect tensional differences in tendons and report. They help regulate effort required to perform movement
736
Regeneration of muscles?
very limited - satellite cells can help a bit - during repair process they can divide and form new myotubes and myocytes. . Sometimes they can merge with existing fibers that helps the repair.
737
After a muscle crush, do pathological changes occur?
Yes, and may lead to breakdown of myofibers and release myoglobin, which can affect renal function and be life threateing
738
Are myofibers syncytial or post-mitotic?
Both. Syncytial means a multinucleated cell that can result from multiple cell fusions of uninuclear cells
739
If nerve supply is cut to a skeletal muscle fiber what happens?
It atrophies.
740
What are two motor neuron diseases?
SMA (spinal muscular atrophy) genetic defect SMN1 which is essential for survival of motor neurons
ALS amyotrophic Lateral Sclerosis - lou gehrig's disease - muscle weakness and atrophycaused by degen of upper and lower motor neurons - 20% familia
Although the cause of ALS is not completely understood, recent research suggests that multiple complex factors contribute to the death of motor neurons. Specific risk factors for ALS have not been conclusively identified, but ongoing research is exploring the possible role of genetics and/or environmental factors.
741
Cardiac Muscles - what are they like?
striated; type 1, RED - with abundant myoglobin, high oxidative, slow twitch)l fibers branch, lots of ATP, one or two nucleus, sheath of endomysial CT
742
Do Cardiac muscles have triads?
No - diads - one cisternae.
743
What kind of junctions are there in cardiac muscles?
Desmosome, Fascia Adherens, and gap:
```
TRANSVERSE component (right angles)- desmosome and fascia
LONGITUDINAL (parallel) - gap.
```
744
What are intercalated discs?
Presence of dark stain - junctional complexes - straight lines of steplike. Transverse runs at right angles - lateral runs parallel
745
Why are gap junctions so cool in cardiac muscles?
Because they allow the message to go along, creating a wave. Syncytium.
746
Do the desmasomes or fasciae adherens do most of the work in cardiac?
Fasciae - anchors sites for actin filaments of terminal sarcomeres (desmosomes - maculae adhernes) bind the cells together, preventing pulling apart under constant contractile activity.
747
What fuels the heart?
Main fuel - fatty acids brought by lipoproteins, stored as triglycerides in lipid droplets.
A small amount of glycogen is present and can be used during times of stress -
Lipofuscin - found near nuclear poles of cardiac muscles.
748
Is contraction in cardiac and skeleton muscles identical?
No, but similar. Cardiac and smooth muscles have leaky calcium gates - in cardiac, trigger for SR release is calcium (not a voltage like in skeleton). Likewise, in Ttubule, there is a calcium DPH channel (not a voltage sensor)
Also Ca+ release in heart is proportional to ca+ entry - not proportional to membrane voltage
749
Are atrial cardiac muscles different than other parts?
Yes, fewer ttubes, smaller, and special granules which act on kidneys to cause sodium and water loss - these OPPOSE aldosterone and antidiuertic hormone - whose effects on kidneys result in sodium and water conservation.
These are high molecular weight polypeptide hormones - atrial natriuretic factor ANP and brain natriuretic factor
750
When is ANP secreted by heart - which becomes an endocrine organ?
secreted from both right and left atria ANP is secreted in response to increased blood flow OR increased venous pressure.
751
What does ANP do where secreted by right and left atria? A lot to do with Kidney - producing more dilute urine and vasodialtion
a LOT -
UPS kidney filtration via vasoconstriction and decreases sodium resorption - creating a large volume of dilute urine.
inhibits antidiuretic hormones from adrenal cortex and nerohypophysis;
inhibits renin secretion fro justaglomeular cells
Vasodialates peripheral and renal blood vessels.
752
What does renin angiotensin system do?
The renin–angiotensin system (RAS), or renin–angiotensin–aldosterone system (RAAS), is a hormone system that regulates blood pressure and fluid and electrolyte balance, as well as systemic vascular resistance. ... If the RAS is abnormally active, blood pressure will be too high
753
What nerve fibers regulate the heart beat?
Sympathetic and parasympathetic.
754
What happens if part of the heart dies?
remaining muscles undergo compensatory hypertophy (heart enlarges) and fibrous CT fills in. new studies suggest maybe a few mature cardiac muscle fibers can mitose.
Coronary arteries are end arteries - they lack collaterals so when she dies, she dies. if they can't get oxygen - the infarct
755
Smooth muscles - characterisitcs?
no ttubes, caveloae near surface, leaky calcium channels, myofilaments form crisscross network; thin filaments have actin and tropomyosin - smooth muscle proteins (caldesmona and calponin) No troponin
756
What and where do we see caldesmona and calponin
In smooth muscles - where we also see thick filaments of myosin arranged in side polar design (striated bipolar). Sliding is similar to skeletal.
Calponin and caldesmon, constituents of smooth-muscle thin filaments, are considered to be potential modulators of smooth-muscle contraction. Both of them interact with actin and inhibit ATPase activity of smooth- and skeletal-muscle actomyosin.
757
What does calmodulin complex do in smooth muscles?
Activates myosin light chain kinase - the enzyme responsible for phophrylation of myosin. ?
758
What causes smooth muscle contraction?
Mechanical, electrical and chemical stimuli.
759
How can estrogen and progesterone work on uterine smooth muscles?
Sex Hormones via cAMP is an example of non-neural control:
Estrogens increase cAMP and promote phosphorylations of myosin and CONTRACT of muscle -
Progesterone has opposite effect - decreases CAMP, promoting dephosphorylation of myosin, RELA
760
What are key filaments in smooth muscle?
Desmin and Viminetin
761
What are dense bodies in smooth muscle and what do they contain?
? They contain alpha-actinin and desmin - similar to Z lines of striated . Both thin and intermediate insert into dense bodies that transmit contractile force to adjacent muscles and the surrounding network
762
What are visceral smooth muscles?
Single-unit smooth muscle, or visceral smooth muscle is a type of smooth muscle found in the uterus, gastro-intestinal tract, and the bladder. In SUVSM, a single smooth muscle cell in a bundle is innervated by an autonomic nerve fiber.
UNITLATERAL vs. Multiunit
Many smooth muscles are like this - large sheets such as found in walls of hollow viscera - intestines, uterus - with a lot of gap junctions, poor nerve supply.
Function in syncytial fashion as a single unit. vs. smooth muscles in eye which is a multiunit - with rich innervation that can produce precise and graded contractions
763
What can single unit smooth muscles generate?
Slow waves -
1. modulated by postganglionic Parasym neurons release ACH, which bind to muscainic or receptors.
2. postganglionic sympathetic neurons that release NE - binding to a1 and b2 adrenergic receptors.
3. hormones such as estrogen (CONTRACT), progesterone (RELAX) or Oxytocin generating IP3, IP3 opens gated ca2_ channels in cisternae
764
How do Multiunit smooth muscles work?
Where fine motor work is needed.
In eye and ductus deferens. No gap junctions -
Postganglionic parasym w Ach, Symp with NE, to a1 and b2 adrenergic receptors
765
How does nerve supply to smooth muscle differ from skeletal?
organs with smooth muscles generally have spontaneous activity - not looking for stimuli. The nerve supply modifies activity rather than initiating.
766
Do adrenergic and cholinergic nerve endings act antagonistically?
Yes - one stimulates, one depresses activity - sympathetic vs. Parasympathetic. which is which? Sympathetic is adrenergic - NE is stimulating - adrenyline!
767
Does the sympathetic nervous stimulate or inhibit?
It depends on the organ.
768
What stimulates the sympathetic nervous system?
Often called the emotional brain, the amygdala pings the hypothalamus in times of stress. The hypothalamus then relays the alert to the sympathetic nervous system and the signal continues on to the adrenal glands, which then produce epinephrine, better known as adrenaline
769
In addition to contractile activity, what else can smooth muscles do?
Synthesize collagen, elastin and proteoglycans
770
Can smooth muscles grow and regenerate?
MORE than the other two types of muscle types. Regeneration is high, pericytes give rise to new cells.
A small number can mitose. Fibers can increase in size and number (ie uterus during pregnancy - hyperplasia AND hypertrophy)
771
Do skeleton muscles have gap junctions?
No, nor do multiunit smooth.
772
What is the difference between alpha 1 and alpha 2 receptors?
Alpha 1 receptors are the classic postsynaptic alpha receptors and are found on vascular smooth muscle. ... Alpha 2 receptors are found both in the brain and in the periphery. In the brain stem, they modulate sympathetic outflow.
773
What is the difference between alpha and beta receptors?
Adrenergic receptors have two main types, namely, alpha and beta receptors. ... Alpha receptors are mostly involved in the stimulation of effector cells and constriction of blood vessels. On the other hand, beta receptors are mostly involved in the relaxation of effector cells and dilatation of blood vessels
774
What does muscarinic mean?
Definition of muscarinic. : of, relating to, resembling, producing, or mediating the parasympathetic effects (such as a slowed heart rate and increased activity of smooth muscle) produced by muscarine muscarinic receptors — compare nicotinic
775
What's the difference between nicotinic and muscar.. receptors?
Muscarinic receptors have a different mechanism of action. ... The main difference between them is their mechanism of action: one uses ions and the other uses G-proteins (Muscarinic). Nicotinic receptors are all excitatory, but muscarinic receptors can be both excitatory and inhibitory depending on the subtype.
776
What are catecholamines and where are they made?
Catecholamines help the body respond to stress or fright and prepare the body for "fight-or-flight" reactions. The adrenal glands make large amounts of catecholamines as a reaction to stress. The main catecholamines are epinephrine (adrenaline), norepinephrine (noradrenaline), and dopamine.
777
What amino acid begins the process of making catecholamines in the adrenal glands?
tyrosine
