Intestines Small and Large

Question 1

Which of the following statements is true?
A The ascending duodenum travels to the right of the root of the mesentery where it forms the duodenojejunal flexure
B The caudal mesenteric artery is the main blood supply to the jejunum
C The vagus and splanchnic nerves supply the mesenteric portion of the small intestines via the celiac and cranial mesenteric plexuses
D All lymph drains into mesenteric LN
E The mucosa is folded into villi that increase the SA 8x in cats and 15x in dogs

Answer 1

A to the left
B cranial mesenteric
C TRUE
D False- some lymph from duodenum carried to hepatic LN and ileum to colic LN
E 8x in dogs and 15x in cats

Question 2

True or false: The duodenocolic fold is formed from the two peritoneal layers of mesoduodenum with the mesocolon.

Answer 2

True

Question 3

Under what vertebrae does the mesentery attach to the abdominal wall? (The root of the mesentery)

Answer 3

L2

Question 4

How many days does it take for total replacement of villus epithelium?

Answer 4

2-6 days

Question 5

What is the name of the 2 peritoneal layers of the mesoduodenum that forma triangular fold with the mesocolon in the region of the pelvic inlet?

Answer 5

Duodenocolic ligament

Question 6

What type of contraction is stimulated in the SI by local stretch reflexes and vagus

Answer 6

rhythmic segmentation
random, small area intestinal smooth muscle
slows down forward motion

Question 7

What do migrating myoelectric complexes do

Answer 7

contractions for sweeping residual undigested material through, cycles every 1.5-2 hours

Question 8

what is the functional unit of the SI?

Answer 8

villus with associated crypts

Question 9

What % of water is abosrbed in jejunum? ileum?

Answer 9

J: 50%
I: 75%

Question 10

Which of the following is true?
A Cholecystokinin is produced by the stomach and cause enzyme release
B Secretin helps with fat digestion
C Carboxypeptidase cleaves proteins into smaller peptides
D SGLUT1 is a sodium dependent glucose transporter for glucose and galactose to enter enterocyte

Answer 10

A SI –> cholecystokinin
B secretin–> release of HCO3- from pancreas
C Carboxypep - one AA at a time (trypsin and chymotrypsin make smaller peptides)
D TRUE

Question 11

What electrolyte abnormalities consistent with distal mechanical obstruction? Proximal GI mechanical obstruction?

Answer 11

hypokalemia, hyponatremia, hypochloremia
metabolic acidosis if loss Na, H2O and HCO3
metabolic alkalosis with vomiting and loss of K, Na, HCl = hypochloremic, hypokalemic

Question 12

What is absorbed in the colon? what is secreted?

WHere?

Answer 12

Re: H2O, Na+, Cl-, short chain fatty acids; PROXIMAL
Sec: K+, HCO3-, mucus

Water modulation DISTAL

Question 13

What percent of colonic mucosal cells are enterochromaffin cells?

Answer 13

5%

Question 14

Which of the following is true?
A. Secretagogues increase the activity of amiloride-sensitive Na+ channels
B. Na+/H+ and CL-/HCO3- are electrogenic channels
C. Na/H exchanger 1 is in the basolateral membrane and Na/H exchanger 2 and 3 are in the apical membrane
D. Aquaporins 2 and 4 are in the apical membrane

Answer 14

A. Aldosterone
Secretagoges switch cells from absorption to secretion
B. electroneutral exchange
C. True
D. Aquaporins -3 and -4 in basolateral membrane

Question 15

What does the cystic fibrosis transmembrane regulator ion channel do in colon?

Answer 15

regulate mucus secretion
influence anion exchangers
modulate Na channels activity
Cl- efflux

Question 16

What increases K+ secretion in colon? (2)

Answer 16

glucocorticoids, aldosterone

Question 17

Name 3 short-chain fatty acids absorbed by colon

Answer 17

butyrate, acetate, proprioante

Question 18

Describe innervation: intrinsic plexuses (2), stimulate or inhibit motility?

Answer 18

Myenteric or Auerbach and submucous or Meissner
STIM:preganglionic vagal+pelvic
INHIB:superior/inferior mesenteric plexus+hypogastric plexus

Question 19

True/false: Features of the immune system in the colon include Foxp3+ regulatory T cells, M-cells and D-cells, intraepithelial lymphocytes, and cryptdins (antimicrobial)

Answer 19

true

Question 20

How much type III collagen is present in proliferative phase of colonic healing? what is the normal %?

Answer 20

30-40%
20% III
(usually more type I- 68%)

Question 21

What do cholecystokinin and secretin do?

Answer 21

Cholecystokinin—> enzyme Release into small intestine

Secretin—> bicarbonate release from pancreas.

Question 22

What factors are associated with intestinal dehiscence? (6-7)

Answer 22

Hypoalbuminemia
Hypotension
Use of blood products
Longer length of bowl resected
Delayed enteral feeding post op
Pre op septic peritonitis
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