GI! Flashcards
(114 cards)
0
Q
Why are the salivary ducts important?
A
- they can become obstructed causing pain
- parotid gland secretes mucus and amylase
- submandibular and sublingual glands are more serous fluid
1
Q
Why are the sublingual veins important clinically?
A
sublingual meds absorbs here
2
Q
What is the anatomical importance of the uvula?
A
it closes off the nasopharynx
- if the uvula is surgically removed, food can reflux into the nasopharynx
3
Q
What is the anatomical importance of teh anterior and posterior arches (palatoglosssal and palatopharyngeal) surrounding the palatine tonsil?
A
Accidentally removing them can cause speech impediments
4
Q
Which salivary duct becomes obstructed most often
A
Stensen’s duct is the most frequent salivary gland to have stones (parotid)
5
Q
Why is Stensen’s duct (parotid) the most frequent gland to have stones?
A
The incidence of stones has been increasing as more people have become more and more dehydrated
- also, salivary amylase is produced here and in the pancreas - the blood levels of amylase reflect the concentrations provided by both glands
6
Q
What structure are involved in cleft palate?
A
upper lip, soft and hard palate
7
Q
how does cleft palate result in malnutrition?
A
cleft palate creates a condition where breathing and chewing cannot occur at the same time so decreased amounts are taken in
8
Q
What are the anatomical parts of the tooth?
A
Cusps - elevations present on the occlusal surface of the crown Alveolus - tooth socket Gomphosis (dento-alveolar joint) Clinical crown Anatomical Crown
9
Q
What is the different between the clinical crown and the anatomical crown?
A
abscesses can never be adequately treated with a bx
10
Q
Why is the different between the slinical and anatomical crown of the teeth important?
A
provides the explanation why dentists say it is so important to floss (you need to clean around the hidden anatomical crown)
11
Q
Some teeth have variable number of roots. Why is this important?
A
The dentist might miss one during a root canal
- tooth morphology is important because the loss of certain teeth means that you have to alter the diet of individuals (ex. no molars for grinding = “soft mechanical diet”)
12
Q
What are the dental formulas for deciduous and permanent teeth?
A
Deciduous Teeth: (approx. 6 mos after birth) Inciser(I)2, Canine(C)1, Premolar(0), Molar(M)2 x4 = 20 teeth
Permanent Teeth (approx 6 y/o): 2I, 1C, 2P, 3M x 4 = 32 teeth
13
Q
Which branch of which nerve does the dentist block?
A
V3: the mandibular division of the trigeminal nerve
14
Q
Why, when the dentist numbs your gums, does your tongue numb?
And why does your tongue not work well afterward?
A
- blocking the mandibular branch will also block part of the tongue
- V 3 is mixed, both sensory and some motor
15
Q
What is a T&A, and what structures are involved?
A
There are 3 tonsils
- 2 (adenoids and palatine) were removed in the past
- Now, mostly just the palatine tonsils are removed surgically
16
Q
Where is the epiglottis and what does it do?
What can happen to it?
A
The epiglottis is attached to the tongue, and gaits food into the esophagus keeping it from going down the trachea
–> it can become infected: epiglottis
17
Q
What are the 5 types of chemoreceptors found in the tongue?
A
Sweet - sugars
Sour - acids (citric, lactic)
Salty - salts (NaCl, NaI, KCl)
Bitter - complex organic molecules; aspirin
Umami - “savory; meaty; brothy” amino acids (MSG - derivec from glutamic acid)
18
Q
Why is tasting bitter important?
A
Bitter tastes are often poisons - explains why people have a strong reaction not to swallow bitter
19
Q
What do filiform papillae do?
A
Touch, pain, temperature
20
Q
What are the different types of tongue papillae?
A
Filiform
Fungiform
Circumvaliate
Foliate
21
Q
What do fungiform papillae do? Where are they found?
A
contain one or more taste buds
- anterior part of the tongue (pink dots)
22
Q
What do circumvallate papillae do? Where are they found?
A
distributed in the shape of an inverted V near the back of the tongue
23
Q
What do folate papillae do? where are they found?
A
In smalll trenches on the sides of the posterior tongue.
24
Which nerve innervates the pharyngeal constrictor muscles?
CNX
25
Which nerve innervates the Upper esophageal sphincter?
CNX
26
Why was the uvula removed?
| Did it work?
We believed that snoring was causing obstructive sleep apnea, so we started surgically removing the uvula, which we thought was causing the obstruction
- It cured the snoring, not the sleep apnea
27
What causes cavities (carries)?
metabolic byproducts of bacteria
| - lactic acid (ex)
28
What is xerostomia and what role does it play in the development of carries?
Dry mouth
| Decreases circulating IgA
29
What is periodontitis?
infection of the aveolar socket (formerly known as pyorrhea); extension of gingivitis
30
What is a Waldeyer's ring and what does it do?
A network of lymphatic tissue that acts as the first line of defense against inhaled or ingested pathogens
31
Which taste receptors are membrane channels?
```
Salt: Na+ channel
Sour: H+ channel
Sweet: 2nd Mess (cAMP)
Bitter: 2nd Mess (IP3)
Umami: 2nd Mess
* ALL result in Ca+ release, which trigger transmitter release
```
32
Which CN provides motor innervation to the tongue? Why is this important?
```
CN XII (hypoglossal)
When trying to localize the site of a tumor or strike, the cranial nerves are examined
If the tongue deviates during the exam, it indicated the location at which the stroke or tumor is acting (the nucleus or nerve root of CN XII)
```
33
Which never innervate the posterior pharynx and why is it important?
CN IX
| It is used to test the gag reflex, say after a stroke
34
What type of cells line the nasopharynx?
Respiratory Tract: Lined by ciliated mucus membrane (Pseudostratified columnar ciliated epithelium with goblet cells)
Air flow: lined with cilia!
Different areas have different linings - impt bc they indicate which types of tumors are likely to be present
squamous cells - squamous cell carcinoma
columnar cells - adenocarcinoma
35
Squamous cell carcinomas are likely to form in the oropharynx, why?
Lined with squamous epithelium (non-keratinizing stratified squamous epithelium)
36
What structures "close" the airway so that food does not travel to the lungs?
the epiglottis
37
What is stomatitis?
an inflammation of the mucus membrane of any of the structures in the mouth (buccal mucosa, gums, tongue, lips, throat or palate)
- can be caused by poor oral hygiene, dietary protein deficiency, poorly fitted dentures, burns from hot food or drinks, toxic plants, of infections/allergic reactions that affect the entire body
38
What causes thrush?
oral candida
39
Where can candida be found?
Anywhere in the oral cavity and esophagus (and other places not covered in GI)
40
What 2 things are needed for the Lower Esophageal Sphincter to function properly?
inner circular esophageal muscle
| loop of diaphragm around esophagus
41
Why does the LES not work well when there is a hiatal hernia?
because part of its function depends upon the diaphragm circling around it
42
What structure drains the foregut, midgut and hindgut?
the portal vein
43
Cirrhosis causes portal hypertension (HTN) - what is the significance of this condition?
Blood can't get through the liver effectively, so it shunts it through the Azygous and Hemiazygous veins in order to get it back to the heart.
- Blood also backs up into other structures like the esophageal veins, causing esophageal varices
44
What drains the majority of the esophagus?
azygous and hemiazygous veins
45
what veins supply the cervical esophagus?
inferior thyroid veins
46
What vein does the abdominal esophagus and gastric fundus drain into?
portal vein
47
The vagus N has been surgically cut (ligated) in the past before its function was fully understood. Why did we do this?
The Vagus N release Ach in the stomach and the stomach produces HCl as a result
- If someone had ulcers that could not be treated in any other way, the nerve would be cut to stop the HCl production
48
Why do esophageal cancers metastasize so quickly?
no serosa
49
What cell type normally lines the esophagus?
stratified squamous epithelium
50
Why are most esophageal cancers not SCC when the main cell type that lines the esophagus is strat. squamous epithelium?
intestinal metaplasia occurring in invading columnar epithelium for the stomach causes Barrett's esophagus and thus adenocarcinoma
51
How can having a hiatus hernia ultimately lead to cancer?
acid reflux leads to intestinal metaplasia (influc of columnar epithelium from the stomach)
52
Name all of the layers of the gut
| common to all of gi tract from esophagus to colon
- lumen
- mucosa (epithelium, lamina propria, muscularus)
- submucosa (dense irrregular CT)
- muscularis externa (inner circular and out longitudinal layers of smooth muscle that are responsible for peristalsis)
- serosasss/adventitia (peritoneum or CT, convey neurovascular bundles)
53
What structure in the GI tract causes the plica circulares to form?
muscularis mucosa
54
what layer in the GI tract houses the glands?
submucosa
55
What are the 2 muscle layers in the Gi tract?
- inner circular
| - outer longitudinal
56
What is the blood supply to the foregut, midgut and hindgut?
Foregut - celiac
Midgut - Superior Mesenteric
Hindgut - Inferior Mesenteric
57
What defines the boundaries of the gut?
The blood supply to each area
58
Which Vagus N can be seen on the anterior surface of the stomach?
Clockwise rotation makes the Left branch of the vagus anterior
59
Which divisions of the gut have both dorsal and ventral mesogastrium?
the foregut is the only place where the structures are tethered both dorsal and ventral by their respective mesogastrium
60
Why is the greater omentum important?
walls off inflammatory processes in the abdomen
| "policeman of the abdomen"
61
What artery comes of the aorta cephalad to the pancreas?
celiac
62
Which arteru comes off aorta cephalad to the pancreas?
celiac
63
Which artery comes of caudad to the body of the pancreas, but cephalad to the insula?
SMA
64
Why is the pyloric antrum of the stomach sometimes removed, and where is it located?
intractable peptic ulcer disease
| before the duodenum
65
where is the pylorus and what does it do?
valve separating the stomach from the duodenum
66
Muscularis Externa - layers and directions
longitudinal layer - fans out
circular layer - also forms the LES and pyloric sphincter
oblique layer
67
What are the folds of mucosa that increase the surface area of the stomach?
Rugae
68
Why does the stomach have 3 muscle layers, not 2 like the rest of the GI tract?
helps churn food
69
What do flattened rugae indicate?
stomach inflammation (gastritis)
70
Why do babies with pyloric stenosis have non-bilous vomiting?
bile is released by the common bile duct in the duodenum, so the bile cannot get backwashed into the stomach as the the enlarge pylorus prevents this
71
What is the classic metabolic disturbance in pyloric stenosis? why?
hypokaemic, hypochloremic metabolic alkalosis
| from the loss of gastric acid via persistent vomiting
72
Different types of ulcers occur in different locations and sometimes this will tell us what is causing them. Name a few examples.
```
Types 1 - V
75% occur on lesser curvature
Type V: NSAIDs; occur on body of the stomach
Type A blood - associated with type I
Type o blood - assoc with all others
```
73
Where is Iron absorbed?
duodenum
74
Where does the foregut end?
after the first portion of the duodenum, a location where the bile and pancreatic ducts drain into the duodenum
75
Why do anterior duodenal ulcers perforate and posterior duodenal ulcers bleed?
the largest arterial supply generally comes from the posterior surface of a hollow viscus (intestines and stomach)
76
When does pancreatic adenocarcinoma occur in most people and what are the symptoms?
50s - 60s
| Pain radiating to the spine
77
Why are most adenocarcinomas inoperable?
The tumor has encased the Sup Mesenteric A and Sup Mesenteric V
78
Why doesn't a persons "guts" spill out onto the floor when they are attacked and eviscerated by a ninja?
the midgut and the hindgut are tethered by the dorsal mesagstrium
79
The midgut and hindgut leave the abdomen during what week of development? Why do they leave?
When do they return?
leave: week 5
They leave to give the abdomen time to enlarge and allows them to move around so that they can rotate 270*
return: week 10
80
What does the midgut include?
2nd part of the duodenum (ampulla of vater) and up to 2/3 of the proximal transverse colon
81
where does the blood supply to the midgut come from?
abdominal aorta at L1
82
What are the branches of the Superior Mesenteric A that supply the midgut?
```
Jejunal A - jejunum
Ileal A - ileum
Ileocolic A - ascend/transverse colon
Appendicular A
Right Colic A - ascend/transverse colon
Middle Colic A - ascend/transverse colon
```
83
Why is knowing the branches of the SMA important?
tells the surgeon where to resect
| - resections are done to include everything perfused by the As and Vs where the primary tumor is located
84
What is the fuel that is used by enterocytes (that also happens to be the most abundant amino acid found in blood)?
Glutamine
85
What is the fuel used by colonocytes (cells of large intestine)>
Short Chain FAs
86
What structures run in the mesentery?
As, Vs and L structures
87
Where does the mesentery insert?
The posterior aspect of the hollow viscera
88
how is absorption of nutrients and water optimized in the small intestine?
increasing the surface area on the intestinal mucosa with plica circulares (large circular folds), villi (folds of mucosa covered by a single layer of enterocytes) and microvilli (projections of enterocyte cell membranes into the lumen, aka brush border)
89
Why is it bad sometimes for lymphatic drainage if a person gets stabbed in the left neck?
Thoracic duct empties into the junction of the left subclavian and internal carotid V
90
What structure in a villi marks the beginning of the lymphatic collection system of the GI tract?
The lacteal
91
What happens if the gut does not rotate 270 degrees?
intestinal malrotation, which causes intestinal obstruction
92
What happens if the vitelline duct does not obliterate?
Meckel's Diverticula
93
Why does Meckel's sometimes bleed?
has gastric tissue in it that responds to circulating blood gastrin and subsequently produces HCl, which erodes the intestinal wall
94
What is the most common malformation of the GI tract? Where is it found?
Meckel's Diverticulum
| the anterior or antimesenteric border
95
what are the disease characteristics of meckel's diverticulum?
```
small bulge in the small intestine, present at birth
#1 cause of painless lower GI bleeding in children
- a remnant of the vitelline duct/yolk stalk
```
96
What 4 conditions can occur if the vitelline duct fails to completely close?
Meckel's Diverticulum
Vitelline Cyst
Vitelline Fistula
Omphalocoele - abdominal closure prior to retraction of intestines (herniated intestinal loops)
97
What is intussusception?
Telescoping of one segment of intestine into another
98
What does it mean when it says that there is a "lead point"?
usually a swelling that leads the telescoping segment into the other
99
What is the most common lead point for a child? An adult?
children: often a swollen lymph node
adult: tumor
100
What is the most common cause of small bowel obstruction? large bowel obstruction?
small: intra-abdominal adhesions
large: cancer/tumors
101
Blood supply to the hindgut (branches of the inferior mesenteric A)
Left colic
Sigmoid branches
Superior Rectal
102
What is the function or consequence of Tenia Coli?
being shorter than the underlying viscus, they create haustra and attachment points for structure
103
What are the divisions of the large intestine?
Cecum --> Ascending Colon --> Transverse Colon --> Descending Colon --> Sigmoid --> rectum --> anal canal
104
Why is the sigmoid colon's floppiness clinically important?
since it is floppy, diseases appear to be on the right side since it can flip over to that side even though the sigmoid is on the left.
105
What is the underlying probem that causes Hirschsprung's disease?
```
Due to failure of the neural crest cells (ganglion cells) to progress in craniocaudal direction
- infant's fail to pass meconium in 1st 24 hours; can also present as chronic constipation (age 2 -3)
#1 cause of colonic obstruction in infants; more common in males
```
106
What layers are missing in diverticular disease?
muscular layers
107
How do true and false diverticula differ?
True: has muscle layers and usually occurs on the right side of the colon; is congenital (not acquired); is more common is asians
108
What is the difference in diverticulitis and diverticulosis?
DIVERTICULITIS: inflammation, usually from infection, occurring in a diverticula
DIVERTICULOSIS: presence of several diverticuli
109
What structure is missing in the appendix?
Villi
110
What are the characteristics of Crohn's disease?
- skip lesions
- can involve anus
- fissures
- bleeding absent 30% of time
111
What are the characteristics of ulcerative colitis?
```
UC always has bloody diarrhea (Crohn's = 70% of time)
Abdominal pain
Fever
Weight Loss
Involves mucosa and submucosa
fistulas and strictures rare
mucosal involvement contiguous
spares anus
```
112
What plus do hemorrhoids form in?
both the internal rectal venous plexus and the interior rectal venous plexus
113
What plexus do suppositories take advantage of for absorption?
internal rectal venous plexus
