GI physiology

Question 1

Which hormones delay gastric emptying?

Answer 1

Gastric inhibitory peptide
CCK
enteroglucagon

Question 2

Which hormones increase gastric emptying?

Answer 2

Gastrin

Question 3

What proportion of acid is produced in the cephalic phase of digestion?

Answer 3

30%

Vagal cholinergic stimulation –> HCl secretion + gastrin release from G cells

Question 4

What proportion of acid is produced in the gastric phase of digestion?

Answer 4

60%

Stomach distention/low H+/peptides –> gastrin release

Question 5

What proportion of acid is produced in the intestinal phase of digestion?

Answer 5

10%
High acidity/distention/hypertonic solutions in the duodenum inhibits gastric acid secretion via CKK, secretin + neural reflexes

Question 6

Where is gastrin produced?

Answer 6

G cells in stomach antrum, duodenum

Question 7

What is the action of gastrin?

Answer 7

Stimulates HCl + IF production from parietal cells
Stimulates pepsin from chief cells
Promotes gastric + intestinal motility, mucosal growth

Question 8

Where is CCK produced?

Answer 8

I cells duodenum + jejunum

Question 9

What is the action of CCK?

Answer 9

Stimulates gallbladder contraction
Stimulates release of pancreatic enzymes
Relaxes Sphincter of Oddi 
Induces satiety
decreases gastric emptying

Question 10

What stimulates CCK?

Answer 10

Partially digested proteins + triglycerides

Question 11

What stimulates gastrin?

Answer 11

Distention of stomach

Question 12

What inhibits gastrin?

Answer 12

Low pH, somatostatin

Question 13

Where is secretin produced?

Answer 13

S cells - duodenum, jejunum

Question 14

What is the action of secretin?

Answer 14

Stimulates bicarbonate release from pancreas
Trophic affect pancreatic acing cells
Decreases gastric acid secretion

Question 15

Where is vasoactive intestinal peptide produced (VIP)?

Answer 15

enteric nerves

Question 16

What is the action of vasoactive intestinal peptide (VIP_?

Answer 16

Increases water and electrolyte secretion from the pancreas + gut.
relaxes smooth muscle of gut

Question 17

Where is somatostatin produced?

Answer 17

D cells of pancreas, stomach + small intestine

Question 18

What stimulates somatostatin release?

Answer 18

Fat, bile salts, glucose in intestinal lumen

Question 19

What is the action of somtastatin?

Answer 19

Inhibits most GI hormones incl. production of Hcl, pepsin, gastrin, pancreatic enzymes, glucagon
Stimulates gastric mucous production

Question 20

which cells produce glucagon?

Answer 20

alpha cells islets of langerhans

Question 21

which cells produce somatostatin?

Answer 21

D cells pancreas

Question 22

what is the main component absorbed by the colon?

Answer 22

Sodium (then water)

Question 23

what is the calorie requirement in a severely unwell patient?

Answer 23

35 kcal/kg/day

Question 24

what is the nitrogen requirement in a severely unwell patient?

Answer 24

0.3-3.5g N/kg/day

Question 25

absorption of fat and protein are dependent on what organ?

Answer 25

Pancreas

Question 26

proteases secreted by the pancreas facilitate absorption of which vitamin?

Answer 26

Vitamin B12

Question 27

is folate absorption dependent on the pancreas?

Answer 27

no

Question 28

which cell type in the stomach secretes mucus?

Answer 28

surface mucosal cells