- most superficial layer of the pericardial sac
- made of strong fibrous CT
what is tamponade? how does it occur and what are the clinical manifestations/symptoms? when is one at risk?
pressure on the heart muscle
fibrous pericardial sac is non-distensible so effusion of fluid into the pericardial cavity results in tamponade
decreases venous return and cardiac output
manifests as Kussmaul's sign (distension of neck veins during inspiration)
at risk 24-48 hrs after heart surgery from clots in chest tubes draining blood
can be treated by pericardiocentesis
- layer of serous pericaridal sac adherent to fibrous pericardium
- inner layer of the serous pericardial sac
- visceral pericardium that touches the heart
- produces pericardial fluid
where are visceral and parietal pericardium continuous?
pulmonary veins, SVC, IVC, and great arteries
what are the two pericardial sinuses and where are they?
recesses of the pericardial cavity situated between vessels of the heart
1. transverse pericardial sinus- posterior to ascending aorta and pulmonary trunk and anterior to SVC
2. oblique sinus- inferior to pulmonary veins and left of the IVC (posterior to heart)
- neither are continuous
where does the right coronary artery course, what does it branch into, and what does it supply?
courses in the coronary sulcus and supplies the right atrium, right ventricle, and part of LBBB
branches into the nodal branch, marginal branch, and if dominant the posterior interventricular artery
divides the atria and ventricles
nodal branches of R coronary artery supplies?
SA and AV nodes
marginal branch of R coronary artery supplies?
posterior interventricular artery/posterior descending (PDA) courses where and supplies what?
courses in the posterior interventricular sulcus and supplies the L and R ventricles, 1/3 of the posterior interventricular septum, and a branch to the AV node
where does the left coronary artery originate, what does it branch into and what does it supply?
it is a short artery that branches within 1 cm of its origin at the left aortic sinus
branches into the anterior interventricular artery/left anterior decending (LAD) and circumflex (LCX)
supplies L and R ventricles, 2/3 of interventricular septum (including AV bundle), L atrium, RBB and part of LBB
where does the LAD course and what does it supply?
courses in the anterior interventricular sulcus
supplies the R and L ventricles and 2/3 of the interventricular septum, including the AV bundle
where does the circumflex artery course and what does it supply?
courses in the coronary sulcus
supplies the L atrium and L ventricle
branches into the obtuse marginal artery
where do coronary artery anastomoses occur?
a. RCA anatomoses with circumflex of LCA after RCA gives rise to posterior interventricular artery
b. LAD hooks around apex to anastomose with posterior interventricular artery
where are common sites of coronary occulsion?
1. proximal part of LAD
2. RCA (proximal)
3. circumflex branch of LCA
4. Left main
where is pain referred to from the heart and how?
afferent pain fibers in heart enter at T1-T4 or T5 on the left side resulting in angina pectoris pain on the left side of the best and medial aspect of the upper arm and forearm (T1 dermatome)
which vessels enter the right atrium?
SVC and IVC as well as ostium of coronary sinus and openings of anterior cardiac veins
smooth walled part of the R atrium which is remnant of sinus venosus
makes up the SA node and coronary sinus
separates sinus venarum from part with pectinate muscles
looks like a thick portion of heart muscle in a crescent shape at the opening into the right auricle
origin of the pectinate muscles
parallel ridges in the rough-walled part of the atria of the heart (anterior wall and auricle)
in the interatrial septum of R atrium
remnant of foramen ovale
in fetal life it permits oxygenated blood to bypass lungs by shunting blood from right to left atrium
separates the R atrium from the R ventricle in the right AV orifice
three leaflets (anterior, posterior, septal with anterior facing closest to you)
rounded or irregular muscular columns which project from the inner surface of the right and left ventricles of the heart (rough-walled part)
conical pouch representing entrance from the right ventricle into the pulmonary artery and pulmonary trunk.
wall of the infundibulum is smooth
right papillary muscles
anterior/great, posterior, septal
when contracted prevents prolapse of tricuspid valve
septomarginal trabecula or moderator band
extends base of anterior papillary in R ventricle to interventricular septum and contains RBB of AV bundle
which valve separates the RV from the pulmonary trunk?
pulmonic semilunar valves
which part of the left atrium has pectinate muscles?
which vessels empty into the left atrium?
the 4 pulmonary veins (2 to each lung)
mitral valve/bicuspid valve
closed by anteriomedial and posteriolateral leaflets
separate the L atrium and L ventricle
mitral valve stenosis
a. where can the heart sound be best heard
b. what heart changes occur
c. what happens in the lungs
d. what is a common complication
a. can be heart at left 5th intercostal space slightly medial to mid-clavicular line
b. as result the the left ventricle regurgitates into the left atrium causing its enlargement
c. if further progressive narrowing of the orifice occurs, blood builds up in left atrium causing pulmonary congestion in the lungs (pulmonary hypertension) and strain on the right side of the heart-->R ventricle hypertrophies
d. blood clots are common complication and if dislodged from the LV can enter systemic circulation-->carotid arteries-->brain-->stroke
smooth walled part of L ventricle to ascending aorta through aortic semilunar valve
aortic semilunar valve
right, left and posterior cusps
left papillary muscles
two: anterior and posterior with chordae tendineae attached to leaflets of mitral valve which contract during ventricular contraction
pacemaker (70 bpm)
in sinus venarum of right atrium near entrance of SVC
initiates wave of depolarization-->atria contract
in interatrial septum near right AV orifice
stimulated by depolarization of atria muscles
delays waveof depolarization from passing to ventricles until atria fully contract
rate of 50-60 bpm
AV bundle of His
passes into interventricular septum
divides into RBB and LBB
causes paillary muscles to contract
spread depolarization to R and L ventricles
(the septomarginal trabecula/moderator band carries purkinje fibers from RBB to base of anterior papillary muscle)
what occurs with an AV block?
conduction is slowed through the AV node or is not transmitted
complete AV block: contraction of atria and ventricles dissociated and chambers beat independently
atria may continue to contract about 70 bpm and pacemaker may develop in the AV bundle distal to site of block so that contraction of ventrcles occurs at rate of 30-40 bpm
largest venous channel of the heart
located in the coronary sulcus and passes to the posterior surface of the heart, just below IVC
the major veins of the heart empty into the coronary sinus which inturn empties directly into the right atrium
great cardiac vein
runs from apex superiorly along anterior interventricular sulcus and veers left to empty into coronary sinus
middle cardiac vein
travels with the posterior interventricular artery in the posterior interventricular sulcus
small cardiac vein
drains blood from posterior and lateral R ventricle
runs along the margin of the heart (coronary sulcus) with the marginal branch of the right coronary artery
will meet up posteriorly with great cardiac vein to coronary sinus
anterior cardiac veins
drain blood directly from anterior R ventricle to R atrium
where does the heart get its parasympathetic innervation?
preganglionic parasympathetic axons from vagus nerve synpase in terminal ganglia
then postganglionic parasympathetic axons from terminal ganglia in cardiac plexus synpase in SA node, AV node, and walls of coronary arteries
where does the heart get its sympathetic innervation?
postganglionic sympathetic axons from cervical and upper thoracic splanchnic nerves (which have cell bodies in superior, middle, and infervior cervical paravertebral ganglia and in the T1-T5 paravertebral ganglia) synpase in SA and AV nodes and walls of coronary arteries
how are the cardiac plexus sensory fibers carried back to the CNS?
a. sensory fibers innervate varoreceptors and chemoreceptors in the heart and aortic arch which course back to CNS with vagus nerve
b. pain sensations are carried back with synpathetic nerves and enter CNS from T1-T5 (which is why pain is reffered to T1-T5 dermatomes ex. angina pectoris)
what are the heart sounds and what do they correspond to?
cuased by acceleration/deceleration of blood flowing through valve
S1: closing of mitral/tricuspid valve (beginning of systole)
S2: closing of aortic/pulmonary valve (end of systold and beginning of diastole)
where do you put the stethoscope to best hear the heart sounds?
1. Aortic region (between the 2nd and 3rd intercostal spaces at the right sternal border) (RUSB – right upper sternal border)
2. Pulmonic region (between the 2nd and 3rd intercostal spaces at the left sternal border) (LUSB – left upper sternal border)
3. Tricuspid region (between the 3rd, 4th, 5th, and 6th intercostal spaces at the left sternal border) (LLSB – left lower sternal border)
4. Mitral region (near the apex of the heard between the 5th and 6th intercostal spaces in the mid-clavicular line) (apex of the heart)
what are the structures of the foregut?
lower esophagus, spleen (mesodermal derivative), liver, gallbladder, biliary ducts, stomach, pancreas, prox 1/2 of duodenum
which artery supplies the foregut?
where does the celiac artery originate from and branch into?
branches from abdominal aorta just inferior to aortic hiatus of diaphragm
in 1 cm it divides into the
a. splenic artery
b. left gastric artery
c. common hepatic artery
what does the splenic artery supply? (include branches)
2. neck, body, tail of pandreas
3. left side of greater curvature of stomach (by left gastroepipolic/omental artery)
4. fundus of stomach (by short gastric arteries)
what does the left gastric artery supply?
1. most of lesser curvature of stomach
2. abdominal part of esophagus
which artery is subject to erosion by ulcer in the lesser curvature of the stomach?
left gastric artery
what does the common hepatic artery branch into?
1. proper hepatic artery
2. gastroduodenal artery
what does the proper hepatic artery supply? (include branches)
1. lesser curvature of stomach (R gastric artery)
2. liver (R and L hepatic arteries)
3. gallbladder (cystic artery, off of the R hepatic artery)
what does the gastroduodenal artery supply? (include branches)
1. foregut part of duodenum
2. superior head of pandreas (by anterior and posterior superior pancreaticoduodenal arteries)
3. right side of greater curvative (R gastroepiploic/omental artery)
which artery is subject to erosion by ulcer of duodenum?
gastroduodenal artery from the common hepatic
generally mobile, suspended by mesentery
which structures are peritoneal?
stomach, first 1/3 of duodenum (1st part), jejunum, ileum, cecum, appendix, transverse colon, sigmoid colon, superior rectum, liver, spleen, tail of pancreas
in fetal life suspended by mesentery, but lost in development
which structures are secondarily retroperitoneal?
distal duodenum inferior to entrance of bile duct (2nd-4th parts), ascending colon, descending colon, head/neck/body of pancreas
"PADD" (pancreas, ascending, descending, duodenum)
were never suspended by mesentary
which structures are primarily retroperitoneal?
kidneys, adrenal glands, ureter, bladder, aorta, IVC, esophagus (thoracic) and rectum
which structures are retroperitoneal?
supradrenal glands, aorta/IVC, duodenum (second and third segments), pandreas (except tail), ureters, colon (only ascending and descending), kidneys, esophagus, rectum
which ligaments suspend the spleen?
gastrosplenic and splenorenal ligaments
which arteries and veins supply/drain blood from spleen?
Splenic artery reaches spleen by coursing posterior to stomach and superior to pancreas (very kinked)
Drained by splenic vein which is posterior to body and tail of pancreas
what are the functions of the liver?
exocrine gland: produces and secretes bile into the biliary duct system
endocrine gland: plasma proteins, release of glucose/lipoproteins
processes nutrients, regulates glucose, detoxifies drugs/toxins, stores triglycerides and vitamin A
which ligaments suspend the liver?
falciform ligament (ends inferiorly at umbilicus), coronary ligament, and lesser omentum (lesser curvature of stomach to liver)
round ligament of uterus/ligamentum teres hepatis
at inferior end of falciform ligament
remnant of fetal umbilical vein
what are the four anatomic lobes of the liver and what separetes?
1. left 2. right 3. quadrate 4. caudate
falciform ligament and ligamentum venosum (remnant of fetal ductus venosus) separate anatomic left and right
what are the two functional lobes of the liver and what do they include?
1. func left: left lobe, quadrate, and caudate
2. func right: right and part of caudate
contain separate arterial blood, venous drainage, and biliary drainage
separated by interconnecting gallbladder and IVC
what is contained in the porta hepatis and where is it located?
portal triad= hepatic ducts, portain vein (70% of blood) and proper heptic (30%)
in the hepatoduodenal ligament
what drains the liver and into what?
hepatic veins into IVC
what is the function of the gallbladder?
stores and releases bile produced by the liver in response to CCK in presence of fats
what artery supplies the gallbladdeR?
cystic artery (branch of R hepatic artery)
what is the path of bile from the liver?
R and L common hepatic ducts-->common hepatic duct+cystic duct-->bile duct-->posterior to duodenum and through head of pancreas-->joins with main pancreatic duct-->hepatopancreatic ampulla-->enters second part of duodenal papilla
what suspends the stomach?
greater and lesser omentum
which ligaments are associated with the lesser omentum?
extends from lesser curvature to liver
hepatoduodenal ligament and hepatogastric ligament
omental bursa/lesser peritoneal cavity
posterior to lesser omentum and stomach
bounded anteriorly by hepatoduodenal ligament, posteriorly by IVC, superiorly by caudate lobe of liver, inferiorly by duodenum
communicates lesser and greater peritoneal cavity
which ligaments are assocaited with greater omentum?
extends from greater curvature to encircle the spleen and reflect back to dorsal wall
gastrocolic ligament extends from greater curvature to transvere colon
splenorenal ligament extends from spleen to dorsal body wall
what are the functions of the pancreas?
endocrine: glucagon, insulin, somatostatin, pancreatic polypeptides
what suspends the pancreas?
only tail is peritoneal, located in splenorenal ligament
what supplies/drains the pancreas?
head has uncinate process which is enclosed by the duodenum and supplied by pancreatoduodenal branches of the gastroduodenal and SMA
splenic vein and SMV join to form portal vein posterior to neck
SMV and SMA pass porterior to neck and anterior to uncinate process
Innervations of the foregut
1. parasympathetic: vagus nerves, in terminal ganglia
2. sympathetic: pregangiolic sympathetic axons in lower thoracic splanchnic nerves (greater splanchnic nerves)from T5-T9 and celiac ganglia
3. visceral pain fibers back in greater splanchnic nerves
4. sensations that are not pain carried back in vagus nerves
what structures are contained in the midgut?
distal duodenum inferior to entrance of bile duct, jejunum, ileum, cecum , appendix, ascending colon, prox 2/3 of transverse colon
what main artery supplies the midgut?
superior mesenteric artery
leaves aorta 1 inch below celiac artery (can trace middle colic supplying the transverse back to SMA)
what are the branches of the SMA and what do they supply?
1. anterior and posterior inferior pancreaticoduodenal branches-->midgut part of duodenum and inferior head and uncinate process of pancreas
2. intestinal branches-->jejunum and ileum (arcades and vasa rectas)
3. ileocolic-->distal ileum, appendix (appendicular artery), cecum, prox ascending colon
R colic-->ascending colon
Middle colic-->prox 2/3 of transverse colon
what are the parts of the duodenum? which parts are peritoneal/retroperitoneal? which part are supplied by which arteries?
1. from pylorus to superior duodenal flexure (only part that is peritoneal): foregut, supplied by the celiac trunk
2. descending part: inferiorly to L3
3. horizontal part: R to L anteror to body of L3 and corssed anteriorly by SMA and SMV
4. ascending part: superiorly left of L3 to left of L2 (at duodenojejunal junction)
parts 2-4 are midgut, supplied by SMA, and enclose head of pancreas
where does the pancreatic duct enter the duodenum?
through the major duodenal papilla (known as Ampulla of Vater) at second part of duodenum
represents junction between the embryological foregut and midgut lies just below the major duodenal papilla
ligament of Treitz
suspensatory ligament at duodenojejunal junction (contains muscle from R cruz of diaphragm)
jejunum begins left of L2
how can you tell the difference between the jejunum and ileum?
jejunum has simple arcades and long vasa recta, also thicker walls, larger luminal diameter, more prominent plica circulares, greater vascularity
ileum has complex/branched arcades and short vasa cecta, also more fat in mesentary and contains Peyer's patches in wall
which parts of the colon are in the midgut?
cecum, ascending colon, proximal 2/3 of transverse colon
what are characteristics of the colon?
1. larger luminal diameter than SI
2. taeniae coli
3. haustrations or sacculations
4. omental appendices
3 independent longitudinal bands of smooth muscle from appendiz to sigmoid colon/rectal junction
form because teniae coli are shorter than total length of colon
globules of fat covered by peritoneum suspended from teniae coli
where is the appendix located? what suspends the appendix? what supplies the appendix?
inferior to iliocecal opening
peritomeal, suspended by mesoappendix
supplied by appendicular artery (branch of ileocolic)
what is appendicitis and how/where does it present?
result of obstruction by stool-->fecalith (adults) or hyperplasia of lymphatic tissue (children)
pain is referred by the lower splanchnic to umbilical
McBurney's point: 1/3 distance from ASIS to umbilicus in the lower right quad
where is the ascenidng colon? what is it fused to? what supplies it?
extends to R colic/hepatic flexure to the transverse colon
it is fused to the R posterior abdominal wall
supplied by R colic artery and middle colic artery
what suspends the transverse colon? what supplies the transverse colon of the mid-gut?
posterior greater omentum
middle colic artery
where does the mid-gut get its parasympathetic innervation?
from preganglionic presympathetic axons in the vagus and neurons in the terminal ganglia
where does the mid-gut get its sympathetic innervation from?
lower thoracic splanchnic nerves (greater, lesser, and least) from T5-T 12 and neurons in celiac and superior mesentery ganglia
where is pain in the mid-gut referred (SI versus colon) and how (aka through which spinal nerves)?
visceral pain fibers go through the lower splanchnic back to the CNS
from from SI is referred through T5 to 10 dermatomes in the epigastric and umbilical region
from cecum, appendix, AC, 2/3 of TC referred through T10-T12 to umbilical, hypogastric, and lumbar region
how do visceral sensations other than pain get back to CNs from the mid-gut?
what are the structures of the hind-gut?
distal 1/3 of transverse colon, descending colon, sigmoid colon, rectum, anal canal
which structures of the hind-gut are peritoneal or retroperitoneal?
sigmoid and distal 1/3 of transverse colon are peritoneal, descending colon and upper rectum are secondarily retroperitoneal, lower rectum and anal canal are primarily retroperitoneal
what artery supplies the hind-gut and where does it originate?
inferior mesenteric artery , which leaves aorta 4 cm above bifurcation into the common iliac arteries
why is the splenic flexure a common site for ischemic bowel infarction?
distal parts of the vascular beds of the middle colic branches of the SMA and the left colic branches of the IMA anastomose here
what are the branches of the IMA and what do they supply?
1. left colic artery-->descending colon and dital 1/3 of transvere colon
2. sigmoid arteries-->sigmoid colon
3. superior rectal artery-->rectum and anal canal to pectinate line
(middle rectal artery of internal iliac-->rectum and anal canal above pectinate line)
where is the descending colon located?
from transverse colon at splenic flexure to the left iliac fossa
where is the sigmoid colon located and what suspends it?
iliac fossa to rectum at S3 vertebra
suspended by sigmoid mesocolon
what is different about rectum from the rest of the colon?
end of teniae coli, haustrations, omental appendices
ampulla of rectum
inferior aspect of rectum is dilated to store feces
where does the hind-gut get its parasympathetic innervation from?
pregangionic axons in pelvic splanchnic nerves from sacral spinal (S2-S4) and terminal ganglia
where does the hind-gut get its sympathetic innervations from?
lower thoracic and lumbar splanchnic from T11-L2 and neurons in the inferior mesenteric ganglia
how do pain sensations from the hind-gut reach the CNS and where are they referred to, and how?
visceral pain to the lower thoracic and lumbar splanchnic from T11-L2 and referred to hypogastric and iliac regions
how do sensations other than visceral pain get to CNS from hind-gut?
pelvic splanchnic nerves
Which nerves are sympathetic, post-ganglionic splanchnics and what is their path of innervation?
presynaptic fibers from upper thoracic vertebral levels-->sympathetic paravertebral ganglia via white rami-->synapse in upper thoracic and lower cervical ganglia-->immediately exit both ganglia and sympathetic chain directy to thoracic viscera
do not re-enter spinal nerve (no grey rami) and don't travel up and down sympathetic chain
Which nerves are sympathetic, preganglionic splanchnics and what is their path of innervation?
greater, lesser, and least thoracic splanchnic nerves, lumbar splanchnic nerves, sacral splanchnic nerves
fibers originally enter sympathetic chain via white rami but don't synpase in paravertebral ganglia-->prevertebral ganglia in the abdomen or pelvis where they will synapse
what does the greater splanchnic orginate and what is its destination?
what does the lesser splanchnic orginate and what is its destination?
T10-T11-->superior mesenteric ganglia
what does the least splanchnic orginate and what is its destination?
where is the destination of the lumbar splanchnic nerve?
inferior mesenteric ganglia
what is the destination of the sacral splanchnic nerve?
what are the parasympathetic, preganglionic splanchnic nerves and what is their path of innervation?
S2-S4 directly to intrinisic ganglia of descending colon, sigmoid colon, rectum, pelvic viscera
should also include the vagus nerve (brain stem-->thoracic viscera, foregut, midgut)
what is the main venous drainage ssytem of the gastrointestinal structures below the diaphragm?
hepatic portal system (hepatic portal vein)
where is the hepatic portal vein formed? what drains into it?
formed posterior to the neck of the pancreas when the SMV unites with the splenic vein
normally the IMV drains intot he splenic vein, but can drain into the SMV or all 3 may merge at a single point
what drains the foregut?
what drains the midgut?
what drains the hind-gut?
IMV, which usually empties into the splenic vein
which veins empty directly into the portal vein other than the splenic and SMV (perhaps IMV)?
left and right gastric veins which drain the stomach including the lesser curvature and abdominal part of the esophagus
NOT the same as the hepatic portal vein
drain blood from hepatic sinusoids and empty into the IVC just below the diaphragm
how do portal-systemic anastomoses occur?
in cirrhosis of the liver, obstruction of the portal vein and hypertension in the portal system occur which causes retrograde flow of portal venous blood from GI strctures entering the liver
retrograde flow forces portal venous blood into capillary beds which also drain into tributaries of the superior or inferior vena cava and here portacaval anastomoses are established to bypass the liver
what are the sites of portacaval anastomosis?
1. esophageal varices: wall of esophagus at junction of capillary bed draining into the left gastric/coronary vein and esophageal tributaries of azygos vein
2. wall of rectum at junction of internal rectal plexus (drains into rectal veins) and external rectal plexus (middle/inferior rectal veins)-->internal hemorrhoids
3. anterior abdominal wall at junction of capillary beds draining into para-umbilical veins (course in falciform ligament) and tributaries of superficial epigastric veins (drain anterior abdominal wall)-->caput medusa: varicose superficial epigastric veins radiating from umbilicus
Names the veins
what are the parts of the mediastinum and what are the boundaries?
1. Superior (between first thoracic vertebra and first rib and between sternal angle and intervertebral disc between T4 and T5) 2. Middle 3. Posterior (above the sternal angle and between the pericardium, vertebral column, and diaphragm) 4. Anterior
what structures does the superior mediastinum include?
trachea, brachiocephalic vein, thymus, aortic arch, esophagus, thoracic duct
what structures does the middle mediastinum contain?
heart, ascending aorta, pulmonary trunk, pulmonary veins, phrenic nerve
what structures does the posterior mediastinum contain?
esophagus with vagus nerves, descending aorta, thoracic duct, sympathetic trunks
what structures does the anterior mediastinum contain?
smaller vessels and nerves, fat and connective tissue, thymus in child or remnant of thymus
what are the layers of the superior mediastinum?
endocrine, venous, arterial, respiratory, digestive
what is contained in the endocrine layer of the superior mediastinum?
contains thymus in children or remants of thymus in adults (will extend inferiorly into the anterior mediastinum in children)
what is contained in the venous layer of the superior mediastinum?
SVC (descends on right side and drains into RA)
left and right brachiocephalic veins
where are the brachiocephlic veins formed?
- formed posterior to a sternoclavicular joint by union of an internal jugular vein and subclavian vein
what is the pathway of the brachiocephalic vein and where does it receive from?
- left brachiocephalic vein crosses the midline behind the thymus or remnants and recieves interior thyroid veins and the left superior intercostal vein
what is contained in the arterial layer of the superior mediastinum?
arch of the aorta and its 3 branches
what are the 3 branches of the aorta and what do they divide into?
brachiocephalic, left common carotid, left subclavian
the brachiocephalic artery divides into the right common carotid and the right subclavian
remnant of the fetal ductus arteriosus between the left pulmonary artery and arch of the aorta
in fetal life, shunts blood from the pulmonary trunk directly into the arch of the aorta to bypass the lungs (oxygenated blood comes from the mother via placenta)
what is contained in the respiratory layer of the superior mediastinum?
trachea (bifurcates at sternal angle to L and R main bronchi)
which vessels cross over the left and right main bronchi?
arch of aorta passes over left main bronchus and azygos vein passes over the right main bronchus
if the trachea is seen in a cross-section image, which area must the cross-section be through? what main structure of the mediastinum will not be present?
the neck of the superior mediastinum
the heart will not be seen since it lies in themiddle mediastinum interior to the trachea bifurcation
what is contained in the digestive layer of the superior mediastinum?
esophagus, thoracic duct, left and right vagus nerves, left recurrent laryngeal nerve, left and right phrenic nerves
what indents/constricts the esophagus?
indented on the left by arch of aorta and indented anteriorly by left main bronchus
also, origin of esophagus at neck and at esophageal hiatus of diaphragm
what is the course of the thoracic duct?
arises from the cisterna chyli below the diaphragm and courses therough the posterior and superior mediastinum posterior to esophagus
terminates in the root of the neck on the left at the origin of the left brachiocephalic vein (at junction of the left subclavian and left internal jugular vein) to drain lymph
what are the courses of the left and right vagus nerves and what are the branches?
pass through the superior mediastinum and enter posterior mediastinum to pass posterior to root of lung and form esophageal plexus on the esophagus
also left and right recurrent laryngeal nerves
pulmonary and cardiac branches to end at cardiac plexus
what are the courses of the left and right recurrent laryngeal nerves?
the left vagus nerve crosses the arch of the aorta and gives off the left recurent laryngeal nerve in the superior mediastinum which hooks under arch posterior to the ligamentum arteriosum and courses superiorly to the larynx
the right recurent laryngeal nerve branches from the right vagus nerve at the root of the neck, hooks around the right subclavian artery and is NOT in the superior mediastinum
what is the course of the left and right phrenic nerves?
pass through superior mediastinum to middle, pass anterior to root of lung and descend to innervate the diaphragm
what is the course of the desending aorta in the posterior mediastinum?
begins at the sternal angle, gives rise to posterior intercostal arteries that supply the thoracic wall, bronchial arteries that supply lung tissue, and esophageal arteries
what type of muscle does the esophagus have?
skeletal in its upper third
smooth muscle in its lower third
mix of both in the middle
what is the course of the azygos vein?
formed by the union of the ascending lumbar veins and right subcostal veins at the level of T12
ascends in the posterior mediastinum before arching over the right main bronchus posteriorly at the root of the right lung where it joins the SVC
"arch of the azygos vein" (arcus venae azygos) is an important anatomic landmark
- sternal angle
hemiazygos drains into the azygous along with other tributaries such as bronchial veins, pericardial veins, and posterior right intercostal veins
what is the course of the hemiazygos veins?
similar structure to azygos vein on the opposite side of the vertebral column (left) and drains into the azgous after crossing midlineat T8
drains the left posterior intercostal veins
what is the course of the accessory hemiazygos vein?
vein on the left side of the vertebral column that generally drains the fifth through eighth intercostal spaces on the left side of the body
are the kidneys peritoneal, secondarily retroperitoneal, or primarily retroperitoneal?
embedded in perirenal and pararenal fat
where are each of the kidneys located? which is higher than the other?
left: anterior to 11th and 12 rib
right: anterior to 12th rib
left is superior
renal hilus (location and contents)
contains renal artery, renal vein, and renal pelvis
renal vein is anterior to renal artery which is anterior to renal pelvis
what are the two regions of the kidneys and what do they contain?
1. cortex: proximal parts of the uriniferous tubules, renal corpuscles, and proximal and distal convoluted portions of the duct system
2. medulla: renal pyramids, which contain the distal parts of the collecting ducts
what is the organization of minor calyces, major calyces, and the renal pelvis?
at apex of each pyramid the collecting ducts open into a minor calyx
2-4 minor calyces form a major calyx
3-4 major calyces unite to form the renal pelvis (expanded upper part of the ureter)
what is the course of the renal arteries?
- arise from the abdominal aorta at L2
- give rise to interlobar arteries that branch into arcuate arteries at the juncture between the medulla and the cortex
- this gives rise to interlobular arteries which give rise to afferent arterioles of the glomerulus
- blood leaves glomerulus via efferent arterioles
where do the renal veins drain into?
empty into the IVC at L2
Because the aorta is on the left side and the IVC is on the right side, where do the right renal artery and left renal vein cross?
- right renal artery passes posterior to the IVC
- left renal vein passes anterior to the aorta just inferior to origin of the SMA
what are the innervations of the kidney and what do they control?
- preganglionic sympathetic axons in lower thoracic or lumbar splanchnic nerves (T11-L2) that synpase in aorticorenal ganglia
- postganglionic sympathetic axons from aorticorenal ganglia distributed to renal arteries to control blood flow to glomeruli
when would one use retroperitoneal approach to removing the kidneys versus transabdominal?
- would use retroperitoneal if contamination of the peritoneal cavity is likely to occur
- would use transabdominal approach if renal vessels or ureters are involed
what structures (muscles/bones) are in close proximity to the kidneys?
- kidney lies along vertebral column against the psoas major muscles
- also related more inferiorly to quadratus lumborum and transvesus abdominis
- superior parts of kidney are protected by the thoracic cage
- posteriorly, superior pole of each kidney related to the diaphragm which separate it from the pleural cavity and 12th rib
if fracture to lower ribs or lumbar transverse processes, which structures should be suspected to also have injury?
which structures would have to be cut and ligated to remove the kidney?
renal artery, renal vein, ureter
potentially accessory renal arteries, which will be omre common on left side and usually inferior to main artery
from what does the left renal vein receive blood?
left suprarenal vein and left gonadal vein (testicular/ovarian)
during kidney transplant, the renal artery and vein are anastomosed to which vessels?
transplant site is iliac fossa
renal artery and vein are anastomosed to external iliac artery and vein
what is the path of the ureters?
tubes containing smooth muscle that arise from renal pelvis at L2 and descend inferiorly on anterior surface of psoas major, cross the pelvic brim (at which time it lies between the external and internal iliac arteries), and enter the posterolateral aspect of the bladder
what arteries supply the ureters?
1. upper third: renal arteries
2. middle third: common iliac artery
3. distal third: superior vesical artery
are adrenal glands peritoneal, secondarily retroperitoneal or primarily retroperitoneal?
what are the zones of the adrenal gland cortex and what do they produce/secrete?
1. zona glomerulosa: aldosterone
2. zona fasciculata: glucocorticoids
3. zona reticularis: reproductive steroids
a. where are chromaffin cells located?
b. what is the function of chromaffin cells?
c. what are they derived from?
d. what are they innervated by?
a. medulla of adrenal gland
b. secrete epinephrine mostly and some noreepinephrine
c. derived from neural crest cells
d. innervated by preganglionic sympathetic axons from lower thoracic splanchnic nerves
what supplies blood to/drains blood from the adrenal glands?
supplied by adrenal arteries that branch from renal arteries, aorta, and inferior phrenic arteries
each drained by single vein
- right adrenal vein drains into IVC
- left adrenal vein drains into the left renal vein
what is the path of the abdominal aorta?
begins at aortic hiatus (where crosses diaphragm T12) and descends inferiorly to left of the midline and ends by bifurcating into common iliac arteries at L4
(just above this bifurcation is a common site for aneurysm)
what arteries branch off of the abdominal aorta and where?
a. celiac artery (forefut) at T12
b. SMA (midgut) at L1
c. renal arteries at L2
d. gonadal arteries between renal arteries and IMA around L2/L3
e. IMA (hindgut) L3 (few cm superior to bifurcation)
f. pair of inferior phrenic arteries supply diaphragm
g. lumbar arteries supply body wall
h. adrenal gland arteries
Name the arteries
where is the IVC formed and where does it run?
L5 by union of common iliac veins ascends through posterior abdominal wall to right of aorta, passes posterior to liver in deep groove and enters thoracic cavity by piercing central tendom of diaphragm (T8) and related fibrous pericardium to drain into RA
Name the tributaries of the IVC
how do the renal veins drain into the IVC and what differs on either side?
drain at L1/L2
right side: renal, adrenal, gonadal veins drain directly into IVC
left: only left renal vein drains directly into IVC; left gonadal, left suprarenal and left adrenal veins drain into left renal vein
- left renal vein crosses anterior aorta just inferior to origin of SMA
what three main collateral routes are available for venous blood to pass to heart if IVC is obstructed?
a. various anastomoses in the abdomen and pelvis that enable blood to reach superficial epigastric (connects superiorly to thoraco-epigastric and drains into axillary vein) and inferior epigastric veins (superior epigastric vein, tributary of internal thoracic vein to enter subclavian)
b. lateral thoracic which connects circumflex iliac vein to axillary vein
c. tributaries of IVC anastomose with epidural venous plexus of veins (within vertebral canal) and azygos/hemiazygos venous system
how is the lumbar plexus formed and what does it divide into?
formed by ventral rami of L1-T4 and found on posterior abdominal wall and greater pelvis
ventral rami branch into posterior and anterior divisions which form femoral and obturator nerves, respectively
what is the path of the femoral nerve?
contains posterior division fibers from L2-L4 ventral rami
emerges from lateral border of psoas major in iliac fossa and passes into anterior thigh posterior to inguinal ligament and lateral to femoral artery
innervates anterior thigh muscles and skin of anterior/medial thigh
gives rise to saphenous nerve
what is the path of the obturator nerve?
L2-L4 ventral rami
emerges from medial (semi-posterior) side of psoas major, crosses pelvic brim and courses anteriorly and inferiorly in lesser pelvis to obturator foramen, through obturator externus to medial thigh
innervates skin of medial thigh and adductor longus, brevis, mangus, gracilis, obturator externus muscles (adduct and flex thigh at hip)
what is the path of the subcostal nerve?
passes between psoas major and quadratus lumborum muscles inferior to 12th rib
innervates abdominal musculature and overlying skin of lateral and anteror abdominal wall
what is the path of the iliohypogastric nerve?
emerges between the psoas major and quadratus lumnorum inferior to the subcostal nerve
innervates abdominal musculature and the skin of the inguinal and hypogastric regions of the lateral and anterior wall
what is the path of the ilioinguinal nerve?
courses inferior to the iliohypogastric nerve and pierces the inguinal canal to pass through superficial inguinal ring
innervates skin of medial thigh, labium majus, and anterior aspect of the scrotum
innervates abdominal musculature and skin of inguinal and hypogastric reions of the lateral and anterior abdominal wall
wht is the path of the genitofemoral nerve?
courses through and then lies anterior to psoas major muscle
divedes into a femoral branch (passes posterior to inguinal ligament to innervate skin of medial thigh) and genital branch (enters inguinal canal through deep inguinal ring and innervates the cremasteric muscle)
what is the path of the lateral femoral cutaneous nerve?
emerges lateral to the psoas major muscle and crosses the iliacus to reach the anterior superior iliac spine
will descend into the lateral thigh passing posterior to the inguinal ligament
Name the nerves of the lumbosacral plexus (take note of the spinal nerves they come from)
Name the nerves of the lumbosacral plexus
what are the three fetal circulation shunts that help bypass blood flow around liver and lungs? where are they located?
1. ductus venosus: oxygenated blood in umbilical vein to bypass liver into IVC and RA
2. foramen ovale: atrial septum to allow oxygenated blood to bypass pulmonary circulation (R to L atrium)
3. ductus arteriosus: SVC drains deoxygenated blood from upper limbs and head into RA-->RV-->pulmonary trunk then shunted to underside of aorta distal to L subclavian, bypasing pulmonary circulation
pressure is higher on the right side or left side of the fetal circulation?
what is the oxygen saturation of the fetal circulation
a. in the umbilical vein
b. in the IVC
c. post-natally/in mother's arterial blood
what are the remnants of fetal circulation?
a. R and L umbilical arteries
b. L umbilical vein
c. ductus venosus
d. foramen ovale
e. ductus arteriosus
a. medial umbilical ligaments
b. ligamentum teres (round ligament of liver)
c. ligamentum venosum
d. fossa ovale
e. ligamentum arteriosum
what are the three major aperatures in the diaphragm and at what levels of the vertebrae are they? (after expiration)
** I ate 10 eggs at midnight
what prevents contents of stomach from reflexing into esophagus?
lower esophageal sphincter (cardiac sphincter)
Name the muscles 1-4
1. psoas major
3. quadratus lumborum
4. transversus abdominus
how many pairs of spinal nerves are there and how are they divided?
8 cervical, 12 thoracic, 5 lumbar, 5 sacral, 1 coccygeal
Name the parts of the spinal cord segment
why is the dorsal root outside of the spinal cord?
derived from neural crest
gray matter has what part of the neuron? white matter?
gray matter: cell bodies
white matter: bundles of axons organized in tracts of fasciculi
where are the cell bodies of the sensory neurons found? motor neurons?
sensory neuron cell bodies found in dorsal root ganglia... no synapses here (pseudo-unipolar)
ventral root cell bodies found in grey matter of ventral horn (only motor axons are found in the ventral root?
sensory nerves in skin that are mostly found in the sermis are innervated by specific types of dorsal roots. what are the general functions of the following:
a. Pacinian corpuscle
b. Meissner's corpuscle
c. Merkel's disc
d. Ruffini ending
e. free nerve ending
a. vibration and pressure ("onion"); deep dermis
b. light touch, will be just beneath epidermis between dermal papillae
c. pressure, texture; will be near hair follicles and in the superficial dermis with ends surrounding a dermal papillae
d. enlarged dentritic endings with elongated capsules; skin stretch
e. pain, temperature
how many dermatomes are there?
how many myotomes?
30 (none for C1) dermatomes
what is the clinical significance of dermatomes?
cutaneous branch of spinal nerve that supplies certain area of skin... can cause referred pain
what do the epimeres form? what do the hypomeres form?
epimeres: deep muscles of back (maintain posture)
hypomeres: intercostal muscles, abdominal muscles, limb muscles
what do the dorsal rami supply?
- supply epimere and skin covering it
- also innervate joints between articular processes of vertebra, deep intrinsic muscles that act on vertebral column, medial 2/3 of back from vertex of skull to coccyx
(some have name: subocciptal nerve (of C1): greater occipital nerve (of C2), cluneal nerves (cutaneous innervation to gluteal region))
what do the ventral rami supply?
- hypomere and skin covering it
- skin, muscle, joints in ventrolateral neck, trunk, extremities
- intermingle to form plexus (except T2-T11) that innervate extremities and neck
- communicate with sympathetic chain of paravertebral ganglia by white and gray communicating rami
(generally all have names)
what is the difference between dorsal and ventral rami in the trunk versus the limbs?
- in trunk, individual sorsal and ventral rami innervate overlapping dermatomes
- in limbs: adjacent ventral rami may join in a plexus to form nerves that supply overlapping dermatomes and myotomes
Name the components of a spinal nerve
what is a irritative nerve lesion and what does it result in clinically?
nerve fibers compressed and firing of sensory or motor is altered
1. sensory-->reduced sensation (hypethesia) or altered sensation (paresthesia)
2. motor-->weakness (paresis)
what is a destructive lesion and what does it result in clinically?
nerve fibers severely compressed or severed, resulting in loss of ability to conduct impulses
1. sensory-->loss in sensory modality (anesthesia)
2. motor-->paralysis of denervated skeletal muscles, fasciculations (random twitches), atrophy
where do the cell bodies of preganglionic neurons lie? post-ganglionic?
pre-ganglionic: in CNS with axons in cranial/spinal nerves
post-ganglionic: in autonomic ganglia in PNS
Fill in the chart concerning the nervous system chemical transmission
which neurons have cholernergic transmission?
- all preganglionic autonomic neurons (sympathetic and parasympathetic)
- all parasympathetic post-ganglionic
which neurons have adrenergic transmission?
- sympathetic post-ganglionic neurons (NE released)
- adrenal medulla (80% epinephrine, 20% NE)
what are the basic steps of transmitter release and removal for each neurotransmitter?
Transmitter release: 1. action potential-->calcium influx-->exocytosis of neurotransmitter
a. Ach hydrolyzed by acetylcholinesterase
b. NE removed by direct Na-driven reuptake into nerve terminals
what are the types of acetylcholine receptors?
Nicotinic and muscarinic
where are the two types of nicotinic receptors located? what type of channels are they? are they excitory or inhibitory?
N1: skeletal muscle end-plates (somatic)
N2: mediate transmission to all ganglionic synpases (autonomic)
ligand-gated channels that depolarize postsynaptic membrane-->excitory
where are the muscarnic receptors located? what type of channels are they? are they excitory or inhibitory?
- on all ANS cells sensitive to Ach (heart muscle, smooth muscle, glands) inlcuding all parasympathetic
- excitory: increase IP3 and DAG, stimulate opening of Ca or increase cAMP
- inhibitory: decrease cAMP and may open K+ channels
what types of channels are epinephrine and noreepinephrine (adrenergic) receptors?
what is the function and mechanism of the following adrenergic receptors? which neurotransmitter is most effective?
a. - excitory effect except in the heart by increasing IP3 and DAG and/or closing K channels; both NE and E equally effective
b. - presynaptic nerve terminal of adrenergic and certain post-ganglionic cholinergic nerve fibers; inhibitory by decreasing cAMP, inhibiting opening of Ca channels, inhbiting transmitter release (such as inhibiting sympathetic outflow to gut); NE and E equally effective
c. - found only in heart and are excitory by increasing cAMP; NE and E qually effective
d. - increase cAMP, but responsible for inhibitory adrenergic actions on target cells such as relaxation/dilation of smooth muscles of bronchioles; E more potent
how many sympathetic pre-ganglionic segments are there? how many paravertebral ganglia?
14 pre-ganglionic segments which can split into
31 pairs of paravertebral ganglia
what do the paravertebral ganglia supply? the prevertebral ganglia?
paravertebral: body wall and thoracic viscera
prevertebral ganglia: inferior to diaphragm and supplies abdominopelvic viscera
why do the cardiopulmonary splanchnic nerves synapse in paravertebral ganglia, not prevertebral ganglia?
above the diaphragm, there is no prevertebral ganglia
what are white rami? what are gray rami?
white rami: preganglionic sympathetic axons that enter and synpase in a paravertebral ganglion (of ventral root)
gray rami: post-ganglionic sympathetic axons that leave paravertebral ganglia, rejoin spinal nerve and go to body wall to innervate sweat glands and vascular smooth muscle
what is the possible fate of white rami?
a. enter ganglia and synapse at paravertebral ganglia then postganglionic cell leaves through Gray Ramus
b. can travel to higher or lower ganglia and synapse there
c. pass through chain without synapsing to then synapse at the pre vertebral ganglia aka splanchnic nerves
* also remember that the splanchnic nerves above tge diaphragm will synapse at the paravertebral ganglia
splanchnic nerves that synapse inn prevertebral ganglia will arise from which spinal vertebral levels?
greater splanchnic T5-T9
where do the parasympathetic preganglionic nerves arise from?
in brainstem and exit with cranial nerves III, VII, IX, X or from sacral cord levels in ventral roots of S2-S4
what is the path of the cranial nerves carrying preganglionic parasympathetic axons?
4 cranial nervs: parasympathetic ganglia in the head
vagus: synpase in terminal ganglia near heart, lungs, walls of GI in foregut and midgut (pharynx to 2/3 of transverse)
sacral: pelvic spanchnic to hindgut terminal ganglia-->transverse colon, descending colon, sigmoid colon, rectum, bladder, erectile tissue, pelvis
where do the preganglionic parasympathetic nerves originate?
in brain stem or S2-4 and these will synpase in ganglia in head or neck or in terminal ganglia at viscera
what does the vagus nerve innervate?
what does the pelvic splanchnic nerves innervate?
vagus: thoracic viscera and 2/3 of abdominalviscera (peristalsis and gland secretion)
pelvis splanchnic: distal 1/3 of gut (perstalsis and gland secretion), bladder contract, dilate erectile tissues
besides motor function, what do parasympathetic nerves also carry?
visceal sensations other than visceral pain
ex. mechanoreceptors, baroreceptors, chemoreceptos\rs
what are the two parts of the respiratory system and what are their main functions?
conducting part: warms, moistens, filters inspired air
respiratory/histological part: gas exchange
what are the 4 areas of the parietal plura and where are they?
1. costal pleura: covers thoracic wall
2. diaphragmatic pleura
3. mediastinum pleura
4. cervical/cupola pleura: extends into root of neck superior to medial 1/3 of clavicle and first rib
where are the visceral and parietal pleura continuous?
root of the lung
during inspiration, where does the inferior extent of the visceral pleura lie in comparison to the parietal pleura?
approximately two rib levels apart
visceral: 6th at midclavicular, 8th at midaxillary, 10th at paravertebral
what are the two recesses of the lungs and where are they located?
costodiaphragmatic (inferior and lateral aspect of lung) and costomediastinal (anterior and medial aspect)
potential spaces at which the visceral pleura and lungs don't completely fill the pleural cavity during inspiration
during maximal inspiration, lingula of superior lobe of left lung fills costomediatinal recess
what innervates the different parts of the pleura?
costal parietal pleura: intercostal nerves
mediastinal pleura and most of diaphragmatic parietal pleura: phrenic nerve
wat is the significant of the potential space? (i.e. function, possible concerns)
- between visercal and parietal pleura is serous fluid which flues the two together and thus when chest wall/parietal pleura move so do the visceral pleura and lungs
- air can enter this area and cause a pneumothorax
describe the different processes of inspiration and expiration. which one is passive?
inspiration: diaphragm descends and elevates and widens the rib cage. external intercostals also elevate rubs and sternum--> negative pressure which pulls air in
expiration: passive recoil of lungs and rib cage. internal intercostals can actively depress ribs and abdominal muscles can push up the diaphragm
what innervates the phrenic nerves? where will pain be referred then if pinching under diaphragm?
phrenic nerves from C3-C5
... may feel dull referred pain in neck
what are the lobes and fissures of the lungs?
right lung: superior and middle, separated by horizontal fissure and inferior separated by oblique fissure
left lung: superior and inferior separated by oblique fissure
where are the best areas to ausculate breath sounds from each lobe of the lungs?
a. superior lobe: anterior and superior thoracic wall
b. inferior lobe: posterior and inferior aspects of the back
c. anterior chest near sternum, inferior to right fourth costal cartilage
why does the left lung only have two lobes? what aspect of the left lung asks as a middle lobe?
heart is on left side-->cardiac impression
below cardiac notch is the lingula which is a tongue like depression which could have been the middle lobe
what structures are in the hilum of the lung and how does the order differ on either lung?
pulmonary artery, pulmonary veins, nerves, lymphatics, primary bronchus
right lung: pulmonary artery is anterior to primary bronchi
left lung: pulmonary artery is superior to primary bronchi
what is the urachus? where is its remnant?
fibrous remnant of the allantois, a canal that drains the urinary bladder of the fetus that joins and runs within the umbilical cord
remnant lies in the space of Retzius, between the transversalis fascia anteriorly and the peritoneum posteriorly.
what 3 bones make up the hip bone and where do they fuse?
ilium, ishium, pubis
fuse at the acetabulum
what are the boundaries of the greater (false) pelvis and what does it contain?
bounded by iliac fossae, sacrum above the promontory (superior part of sacrum) and the anterior abdominal wall
at upper end it flares out and should be considered part of the abdominal davity
contains the iliacus muscle (fills the iliac fossa)
what are the boundaries of the lesser (true) pelvis and what does it contain?
formed by the hipbones, the sacrum below the promontory, and the coccyx
posterior: sacrum and coccyx
anterior: symphysis pubis
contains the obturator internus and piriformis muscles
what are the 3 parts of the true pelvis?
inlet (pelvis brim), outlet, cavity
what forms the pelvic inlet/pelvic brim?
separates the greater pelvis and lesser pelvis; formed by superior aspect of the pubic symphysis, the pelvic brim, and the sacral promontory
what forms the pelvic outlet?
diamond-shaped opening with borders at the inferior aspect of the pubic symphysis, ischiopubic rami, ischial tubberosities, sacrospinous ligamens, tip of the coccyx
what forms the subpubic angle?
ischiopubic rami unite at the pubic symphysis to form the subpubic angle
what is the difference in pelvic inlet and subpubic angles between males and females?
females have oval shaped pelvic inlets and males have heart shaped
females in general have a shallower, wider pelvis
females have a wider pelvic inlet angle (90 degrees) versus males (60 degrees)
how is the pelvic outlet divided and by what?
subdivided into urogenital triangle and anal triangle by coronal line extending between ischial tuberosities with a center point of perineum
what is the smallest dimension of sacral promontory to medial pubic symphysis in the sagittal view?
true (obstretic) conjugate: sacral promontory to midpont symphysis
what is the plane of smallest/narrowest dimension? what is the length?
interspinous distance 10 cm
Name the pelvic bone ligaments and foramens
Name the bony parts of the pelvis (some repeat)
what is the pelvic diaphragm and what are its attachments/boundaries?
boundary between the pelvis and perineum; a funnel shaped structure that consists of skeletal muscle and fascia
supports all pelvic viscera plus rectum and anal canal
base of pelvic diaphragm attaches to bony/facial walls of lesser pelvis below pelvic brim and apex projects posteriorly and inferiorly into anal triangle
what is the urogentital diaphragm and what are its attachments?
separates the perineum below
urethra and vagina transverse it
what sphincters so the pelvic and urogenital diaphragms have and what are their functions?
pelvic: external anal sphincter-->anal continence
urogenital diaphragm: sphincter urethrae-->urinary continence
what are the muscles of the pelvic diaphragm?
1. levator ani
describe location of pubococcygeus muscle
encircles viagina, prostate, and anorectal junction and attaches to the perineal body
describe location and function of the puborectalis muscle
founds the urogenital hiatus and forms part of external anal sphincter
when it contracts, anorectal junction is pulled anteriorly to contribute to fecal continence
describe location of the iliococcygeus muscle. what is different about its attachment?
arises from the tendinous arch, a thickening of the fascia covering the obturator internus muscle and attaches to the anococcygeal raphe between anal canal and coccyx
what muscles make up the levator ani?
pubococcygeus, puborectalis, iliococcygeus
describe the location of the "ischio"-coccygeus muscle
attaches lateally to ischial spine and sacrospinous ligament and medially to the coccyx and sacrum
what/where is the perineal body? (and what converges there?)
perineal body (or central tendon of perineum) is a pyramidal fibromuscular mass in the middle line of the perineum at the junction between the urogenital triangle and the anal triangle.
males: between the bulb of penis and the anus
females: between the vagina and anus
what innervates the muscles of the pelvic diaphragm?
by ventral rami of S2 and S3 spinal nerves and branches of the pudendal nerve
distensible fat and connective tissue that is between the pelvic diaphragm and obturator internus muscle/fascia which can distend when fecal matter enters the lower anal canal
where do the pudendal nerves arise from and what do they innervate?
ventral rami of S2-S4
innervate skeletal muscles in both urogental and pelvic diaphragms
and both external anal and urethral sphincters
describe what results in uterine prolapse, cystocele, and rectocele and what happens in each
pelvic diaphragm weakness
uterine prolapse: cervix, isthmus, body of uterus protrude into superior vagina-->bleeding/discharge
cystocele: bladder herniates into the upper part of the anterior wall of the vagina-->urinary problems
rectocele: rectum herniates into lower part of the posterior wall of the vagina-->defecation issues
if looking at the pelvic diaphragm in a coronal view and can see the obturator internus and tendinous arch, which muscle of the pelvic diaphragm are you looking at?
what are the differences in lining, blood supply, venous drainage, lymph drainage, and innervation of the snal canal above and below the pectinate line?
above the pectinate line:
- anal canal lined by mucosa
- superior rectal artery from IVC
- internal rectal venous plexus-->superior rectal vein-->inferior mesenteric vein-->heptaic portal system
- lymph to internal iliac nodes
- sensory innervation of mucosa by fibers that course w/ autonomic nerves, but insensitve to pain
below the pectinate line:
- lined with skin
- inferior rectal artery, branch of pudental artery
- external rectal venous plexus-->inferior rectal vein-->internal iniliac bein-->internal pudental vein-->of caval system
- lymph to supericifial inguinal nodes
- sensory innervation of skin by inferior rectal branches of pudendal nerve, sensitive to pain, touch, temperature
what is the difference between internal and external hemorrhoids and where can the occur?
internal hemorrhoids: painless protrustion of anal canal covered by mucosa (above the pectinate line) containing dilted veins of internal rectal venous plexus
external hemorrhoids: painful enlargements covered by skin (below the pectinate line) that contain dilated veins of the external rectal venous plexus
what is the difference between the internal and external sphincters of the anal canal?
internal anal sphincter: smooth muscle derived from inner circular muscle layer of the rectum; under involuntary control, innervated by sympathetic nerves that contract and parasypathetic nerves which relax
external anal sphincter: skeletal muscle derived from puborectalis muscle; attaches to skin and perineal body; voluntary control; innervated by inferior rectal branches of pudendal nerve
smooth muscle surrounding the bladder
internal urethral sphincter
smooth muscle at the base of the bladder that is more prominent in males and prevents reflux of sperm into bladder (under sympathetic control)
external urethral sphincter
sksletal muscle encircles urethra in urogenital diaphragm
is the bladder peritoneal, primarily retroperitoneal, or secondarily retroperitoneal?
what are the peritoneum reflection points in the male and female?
in male: rectovesical pouch
in female: vesicouterine pouch and rectouterine pouch
what is the most inferior part of the peritoneal cavity in the male and femle?
rectouterine pouch for females and the rectovesical pouch in males
trigone of the bladder
inner posterior wall of the bladder where at the lateral angles the ureters open and at the inferiorly apex the urethra opens
what are the parts of the male urethra and where are they?
1. protatic urethra: arises from the bladder and passes through the prostate and urogenital hiatus of the pelvic diaphragm to reach the urogenital diaphragm
2. membranous urethra: passes through the sphincter urethrae muscle/external sphincter in the urogenital diaphragm
3. penile urethra turns sharply anteriorly inferior to the urogenital diaphragm and trasnverses the bulb and corpus spongiosum of the penis (... obviously, it's in the penis)
what is the different between the male and female urethrae?
female urethra is distensible because it contains considerable elastic tissue and smooth muscle (why cathters hurt males more than females...)
infections of female urthra more common because shorter and more open to exterior through vestibule of the vagina (why UTIs are like rampant)
where is the ductus deferens and what is its function?
arises from the epididymis adjacent to the testis and trasnverses the inguinal canal then descends into the pelvis to reach the posterior aspect of the urinary bladder to meet up with the ejaculatory duct
transports sperm made by the seminiferous tubules of the testis
where are the seminal vesicles and what is their function?
posterolateral aspect of the bladder lateral to ductus deferens to join the ejaculatory duct
secrete a fructose-rich component of the seminal fluid which contribute to metabolism
what forms the ejaculatory duct, where is it, and what is its function?
formed when ductus deferens joing with duct of seminal vescile just above the prostate and will open onto the surface of the seminal coliculus in the posterior wall of the prostatic urethra (between periurethral and peripheral zones)
function is to (obviously) then transport sperm and seminal fluid through the prostate
where is the prostate gland (what does it surround) and what are its parts/zones and their function?
bellocated below the bladder and surrounds the prostatic urethra (duh)
a. periurethral zone: surrounds the prostatic urethra and contains mucosal and submucosal glands which lubricate the urethra
b. peripheral zone: contains main prostatic glands which secrete a milky component of the seminal fluid that contain prostatic acid phosphatase and prostate-specific antigens which contribute to sperm activation and motility
c. ducts of the prostatic glands open into the prostatic sinuses on either side of the seminal colliculus in the prostatic urethra
what is benign prostatic hyperplasia and where is a common site for is?
enlargement of the prostate and commonly occurs in the periurethral zone resulting in the obstruction of prostatic urethra and urinary flow
what is the common site for adenocarcinoma in the prostate and where can they commonly metastasize? what will be elevated in the blood?
perpheral part of the prostate in the main prostatic glands
urine flow may be altered, may pass urine into blood
can metastasize into the bones of the pelvis, body of vertebrae, or ribs
patients have elevated blood levels of prostatic acid phosphatase and prostate-specific antigen
keep mentioning seminal colliculus... wtf is it?
landmark on the prostatic urethranear the entrance of the seminal vesicles
The margins of seminal colliculus are the following:
the orifices of the prostatic utricle
the slit-like openings of the ejaculatory ducts.
the openings of the prostatic ducts
where is the uterus situated? what muscle type is it made of and what are its parts?
between bladder and rectum
50% anteverted typically at junction of cervix and vagina to lie on the superior aspect of the bladder
fundus, body, isthmus, cervix
where is the fundus of the uterus?
superior to the opening of the uterine tubes located at the junction of the body and the fundus
where does the body of the uterus begin?
below the uterine tubes
where does the cervix begin and end?
inferior to the isthmus at the internal os and continues to the external os which opens into the upper ends of the vagina
what are the parts of the uterine tube? and where are they located?
intramural part: lies inside uterine wall between fundus and body
isthmus: thick muscular wall and extends from uterine wall to ampulla
ampulla: dilated and longest segment
infundibulum: distal segment that terminates in fimbriae and contains the ostium, which opens into the peritoneal cavity
the round ligament of the uterus is a remnant of?
what is the vestibule?
common chamber of the urethra and vagina
what are the two other names for the recto-uterine pouch (one is Dr. White's specifically)? the name that Dr. White prefers is because (has to do with location)?
pouch of Douglas
recto-vaginal pouch-- this is because technically the pouch comes in contact with the rectum and the beginning of the vagina or posterior fornix
what is special about the uterus, uterine tubes, and ovaries in regards to peritoneal?
secondarily peritoneal (aquared mesentery during development)
what is the broad ligament and what are its parts?
fold of peritoneum that forms a mesentery suspending the uterine tubes, ovaries, and most of uterus
mesometrium: adjacent to uterus
mesoalpinx: suspends the uterine tubes
mesovarium: suspends the ovaries
where are the transverse cervical ligaments and what courses with them?
base of the borad ligament
consist of condensations of CT and support the cervix and vagina
uterine artery and vein and ureter course through the trasnver cervical ligaments
during a hysterectomy what may be accidentally ligated?
the ureter because of its proximity to the cervix and uterine artery
immediately after ovulation, where is the ovum?
in the peritoneal cavity after passesing through the peritoneum covering the ovary
where is ectopic implantation most common?
ampulla of the uterine tube
what is a episiotomy?
incision of the posterior wall of the vagin that can be performed during labor to make healing more rapid
what does the meaning "water under the bridge" mean in the female versus the male?
female: ureter passes under the uterine artery
male: ureter passes under ductus deferens
what transverses the urogenital diaphragm?
and vagina in females
what muscles does the perineum contain?
the deep transversus perineus msucles and spincter urethrae/external urethral sphincter which encircles the urethra
what does the deep perineal pouch contain in males and females?
contains sphincter urethrae and deep transversus perineus muscles in both sexes and is between the inferior and superior fasscial layers of the urogenital diaphragm
in female contains urethra and vagina
in males contains the membranous part of the urethra and bulbourethral/Cowper's glands which open into the penile urethra
what does the superficial perineal pouch contain?
crura and bulbs of penis and clitoris, which consist of rectile tissue
what are the path of the two crura, what do they continue as, and what muscles cover them?
attached to the ischiopubic rami and perineal membrane and continue as the corpora cavernosa into the penis and clitoris
ishiocavernosus muscles cover and will contract to limit venous drainage during erection
where are the bulbs in the male and female and what muscles cover them?
in male, bulbs of penis lie in midline, attached to perineal membrane and contains the penile urethra
in females, the bulbs of the vestibule are in the wall of the vestible with the greater vestibular/Bartholin's glands. unlike in the male they are split and will join at the base of the clitoris
covered by the bulbospongiosus muscles which contract to limit venous drainage during erection
in males, when the bulbospongiosus muscles contract what functions do they have in addition to preventing venous drainage?
expel sperm and seminal fluid during ejaculation and urine during micturition
what is the Colles' fascia and what is it continuous with?
"fatty layer" forms the superficial fascial boundary of the superficial perineal space
continuous with the dartos fascia of the scrotum, superifical penile fascia that covers the penis and clitoris and Scarpa's (membranous) fascia of the abdominal wall
what is the deep penile or Buck's fascia?
enclose the 3 erectile bodies, deep dorsal vein, dorsal nerves and arteries (2 corpa cavernosa and corpus spongiosum)
in the female, what is analogous to the scrotum?
what are homologous to the prostate in females?
paraurethral glands of Skene's which lubricate the urethra and vestibule
what artery supplies the pelvic viscera and perineal structures as well as the walls of the pelivs, gluteal region, and medial aspect of the thigh?
internal iliac artery
now the medial umbilical ligament
but gives off vesical arteries to the bladder
only in females
branch of umbilical artery to course through broad ligament and supply the cervix, body, and fundus of the uterus and uterine tubes
artery to ductus deferens arises from and supplies?
inferior vesical artery
supplies the ductus deferens and testis
vaginal artery is a branch of and supplies the?
branch of uterine artery
suplies under the urtery to the bladder and vagina
inferior vesical artery
supplies the inferior aspect of the bladder and prostate
middle rectal artery is a branch of and supplies?
branch of internal pudendal artery
supplies rectum and anal canal ABOVE the pectinate line and seminal vesicles
internal pudendal artery, what does it supply, what is its path and what are its branches
supplies the perineum
exits the pelvis through the greater sciatic foramen and lesser sciatic foramen
courses through the pudendal canal
a. inferior rectal artery: supplies the anal canal below the pelvic diaphragm
b. perineal branch supplies muscles in the superificial and deep perineal pouches and skin of the labia, vestibule, and scrotum
c. artery to the bulb and deep artery of the penis/clitoris supply erectile tissues, bulbourethral bland and greater vestibular gland
d. dorsal artery of the penis and clitoris supplies erectile tissue and skin of penis and clitoris
crosses the pelvic brim to supply the iliacus, psosas major and minor and quadratus lumborum muscles
lateral sacral artery
supplies structures in wall of lesser pelvis and sends branches to sacral canal
what are the pelvic wall branches?
iliolumbar artery and lateral sacral artery
what forms it and what are its branches
ventral rami of S2-S4
passes through greater sciatic foramen and enters pudendal canal after passing through lesser sciatic foramen
inferior rectal nerve, perineal nerve, dorsal berve of the penis and clitoris
inferior rectal nerve
branches from pudental nerve at entrance of pudendal canal
innervtes the external sphincter muscle, skin of anal canal BELOW the pectinate line, and skin covering anal triangle
posterior scrotal nerves: skin of posterior scrotum
posterior labial nerves: skin of labia majora and vestibule
innervates muscles in superifical and deep perineal pouches (transverse perineus, sphincter urethrae, bulbospongiosus, ischiovacernosus muscles)
dorsal nerve of penis/clitoris
innervates skin of penis and clitoris
what conveys pain from structures in the perineum?
what are the motor functions of the pudendal nerve?
maintains voluntary urinary continence (sphincter urethrae)
maintains voluntary fecal continence (external anal sphincter)
supports pelvic visera and helps prevent proapse of structures (urogenital diaphragm and pelvic diaphragm skeletal muscles)
maintain erection (ischiocavernosus and bulbospongiosus)
expulsion of erine from penile urethra and sperm and seminal flud (bulbospongiosus)
what nerves provide sympathetic innervation to smooth muscle and glands in pelvis and perineum?
lower thoracic and lumbar splanchnic nerves that synpase in inferior mesenteric ganglion or cross pelvic brim to synpase in prevertebral ganglia in inferior hypogastric plexus
pain and motor
what are the motor funcitons of the lower thoracic and lumbar splachnic nerves?
facilitate contraction of sphincter vesicae which allows bladder to fill and prevents retrograde ejaculation
facilitates contraction of ductus deferences, prostate, seminal vesicles for emission of sperm and seminal fluid
faciliate emptying of secretory products of bulbourethral and greater vestibular glands (lubricate urethra and vesitbule)
facilitate contraction of internal anal sphincter for fetal continence
what converys pain from GI in hindgut, pelvic viscera, bladder, rectum anal canal above pectinate line? also the fundus, body, cervis of uterus and upper vagina
lower thoracic and lumbar splanchnic
what provides the parasympathetic innervation to smooth muscle and glands in the pelvis and perineum?
pelvic splanchnic nerves
what are the motor functions of the pelvic splanchnic nerves?
facilitate bladder emptying by contracting detrusor muscles
stimulate glandular secretions and peristalsis of hindgut
faclitate emptying of rectum by relaxing internal anal sphincter and contraction smooth muscle in ampulla of rectum
facilitate erection by dilating helicine arteries in erectile tissue
stimulate secretory activity of prostate, seminal vesicles, bulbourethral and greater vestibular glands
describe vesical reflex of micturation
filling stage: no urine sensed stretch receptors in wall innervated by pelvic splanchnic-->CNS-->sympathetic nerves inhibit detrusor to allow bladdr wall to stretch-->pain fibers stimulated by bladder fullness innverated by lumar and lower thoracic splanchnic nerves
emptying stage: CNS activated-->sphincter urethrae and sphicter vesicae relax, pelvic splanchnic nerves cause detrusor to contract; also bulbospongiosus muscle in male contracts; throacoabdominal diaphragm and muscles also contract to increase intrapelvic pressure
this reflex is faciliated by parasympathetic and sympathetic nerves and pudendal nerves
describe process of defecation
visceral afferent fibers mediate distension of rectum and anal canal above the pectinate line to sacral spinal cord via pelvix splanchnic nerves
these facilitate peristalsis by stimulating contraction in smooth muscle in ampulla of rectum
internal anal sphincter and external anal sphincter inhibited
sexual relex steps
- pelvic splanchinic and posganglionic cavernous nerves
- relaxation of vascular smooth muscle, dilation and filling of arteries in erctile tissue of crura and sorpora cavernosa, bulb and corpus spongiosum
- contraction of ischiocavernosus and bulbospongiosus (by perineal branches of pudendal nerve) help maintain
- pelvic splanchnic nerves
- males: stimulae prostate, seminal vesicles, and bulbourethral glands to secrete
- females: vaginal glands and greater vestibular glands secrete, vagina elongates, uterus moves from anteverted to retoverted position
- lower thoracic and lumbar splanchnic nerves
- contraction of smooth muscle in ductus deferens, prostate, and seminal vesicles
- contraction of sphicter vesicae muscle at base of ladder to prevent retrograde ejaculation
- pudendal nerve
- sphincter urethrae is relaxed
- rhythmic contractions of bulbospongiosus muscle propel sperm and seminal fluid
converts the greater sciatic notch to the grater sciatic foramen
right ovarian vein drains into the...
separate deep and superficial pouch
roots of enternal male genitalia and roots of clitoris
where do the bulb and crus converge?
at around the level of the pubic symphyss in the supericial peritoneal pouch to form the penis proper
patient has bilateral ptosis, horizontal diplopia, dysphagia, dysarthria, and weakness in chewing as well as in the muscles of facial expression. weakness increases with use. cardiac and smooth muscle are spared.
what may the patient have? what nerves are affected? what else can cause this?
antibodies attack Ach receptors-->defective neuromuscular transmission
muscles innrvated by cranial nerves primarily affected, especially ocular muscles
many patients may have thymic hyperplasia or thymoma
condition that presents as weakness in limbs caused by axons peripheral myelin defects
what is the mechanism behind botulinum toxin?
it prevents the release of Ach by binding to SNARE proteins at presynaptic membrane
what is a ganglion versus a nucleus?
ganglion- collection of neuron cell bodies situated in the PNS
nucleus- collection of neuron cell bodies inside the brain or spinal cord
what synapses in the sensory ganglia?
nothing... contain cell bodies of either pseudounipolar or bipolar sensory neurons
what synpases in autonomic ganglia?
motor cell bodies
where are neurons in ganglia derived from embryonically speaking?
neural crest ectoderm
what type of neurons are found in the nuclei and where are they derived from embryonically speaking?
skeletal motor neurons and preganglionic autonomic neurons
derived from neural tube
compare oligodendrocytes to schwann cells
- oligodendrocytes form myelin for parts of multiple axons in the CNA
- schwann cells- form myelin for axons or processes in the PNS; only for one segment of a single axon
can CNS axons regenerate if cut? can PNS axons?
CNS axons: no
PNS: if myelinated then yes at rate of 1-4 mm/day
what is affected in multiple sclerosis?
both sensory and motor systems containing axons with myelin formed by oligodendrocytes (thus in CNS) undergo inflammatory reaction that impairs impulse transmission
multiple lesions appear over time and deficients in sensory/motor may be seen in all areas of body
only nerve affected is the optic nerve because all of the myelin sheath of its axons are formed by oligodendrocytes (other spinal/cranial nerves have myelin formed by schwann cells)
patients present with anhydrosis (inability to sweat on certain side of face), ptosis, and miosis (constriction of pupil). what condition is this and what is it caused by?
caused by lesion in either preganglionic or postganglionic sympathetic neurons that innervate sweat glands and blood vessels in face and scalp and 2 smooth muscles in the orbit which elevate uppereyelid and dilate the pupil
(differs from myasthenia gravis which attacks Ach receptors resulting in weakness with use or ocular muscles and muscles of face)
patient presents with impotence, urine retention with increased urinary frequency at night, dizziness on standing, blurred vision, and inability to sweat. what condition is this and what is it caused by?
results from degeneration of preganglionic sympathetic and parasympathetic neurons and of neurons in most ganglia
what causes Hirschsprung's disease and what are the symptoms?
caused by failure of neural crest cells to either migrate into wall of the descending colon, sigmoid colon, or rectum or to differentiate into termial parasympathetic ganglia in these areas
will be an absence of peristalsis in the affected segment and distended bowel proximal to that segment
(huge colon guy)
what is an irritated lesion versus a destructive lesion? what do each of them result in for sensory or motor fibers?
irritated lesion- nerve fibers compressed and firing of the irritated sensory or motor neurons altered
- sensory fibers have reduced sensation (hypesthesia) or altered sensation (paresthesia)
- motor fibers have weakness (paresis) of skeletal muscle
destructive lesion- nerve fiber severely compressed or severed resulting in loss of ability of nerves to conduct impulse
- sensory fibers have loss of sensory modality (anesthesia)
- motor fibers have paralysis and may exhibit faciculations (random twitches) or undergo atrophy
what are examples of anatomic end arteries?
arteries that lack collateral circulation
central artery of retina, interlobular arteries of kidney
Raynaud's disease is characterized by...
arteriovenous shunts that show hyperactive vasocontriction, resulting in cooling of hands and feet
cyanosis may be present in fingers and toes
where does the thoracic duct drain into? what drains into the thoracic duct? and what does not? where do those structure then drain into and what vein do they meet up with?
the thoracic duct drains into the venous system at the junction of the left subclavian and left jugular vein (where they become the brachiocephalic vein), below the clavicle (will go up and come back down)
the thoracic duct collects from any nodes below the diaphragm and the left head, neck, chest, and arm
it does not collect from the right side of the head, neck, right upper extremities, right chest or the LEFT LOWER LOBE OF LUNG
these drain into the right lymphatic duct which drain into venous system at junction of R subclavian and R jugular veins
if there is an overproduction or lack of absorption of cerebrospinal fluid or a blackage into ventricles of the CNS/subarachnoid space, this can cause...
parasympathetic or sympathetic?
mkaes detrusor muscle contract
parasympathetic or sympathetic?
sends preganglionic axons to synpase in prevertebral ganglia
parasympathetic or sympathetic?
contains preganglionic axons that exit the CNS in ventral roots of spinal nerves
parasympathetic or sympathetic?
has preganglionic neuron cell bodies in the spinal cord
parasympathetic or sympathetic?
sends preganglionic axons to synpase in terminal gangia
parasympathetic or sympathetic?
superior cervical ganglion is part of this system
parasympathetic or sympathetic?
parasympathetic or sympathetic?
postganglionic fibers of this system innervate smooth muscle in blood vessels in the upper limb
parasympathetic or sympathetic?
responsible for innervating a smooth muscle that dilates the pupil
parasympathetic or sympathetic?
increases secretory activity of glands in the wall of the GI tract
parasympathetic or sympathetic?
functions in dilating vascular smooth muscle in erection
parasympathetic or sympathetic?
preganglionic axons course in white rami
parasympathetic or sympathetic?
preganglionic axons exit the CNS in cranial nerves V, VII, IX, X
neither... only III, VII, IX, and X carry preganglionic parasympathetics out of brainstem
parasympathetic or sympathetic?
postganglionic in gray rami
sympathetic (cardiopulmonary splanchnic)
parasympathetic or sympathetic?
lesion of this system results in miosis (pupil constriction), ptosis, anhydrosis
lambert-eaton syndrome is caused by... and results in...
immunologic disorder of calcium ion channels in nerves at end plate
associated with small cell carcinoma of lungs
proximal muscles in limbs are primarily affected
muscles innervated by cranial nerves paraed
repetitive contractions of affected muscle can temporarily increase strength