Gastric- Alcon

Question 1

gastrin is synthesized by what cells

Answer 1

G cells of stomach

Question 2

what is the function of gastrin

Answer 2

stimulate gastric acid secretion
gastric motility

Question 3

cholecystokinin is synthesized by what cells

Answer 3

I cells of intestines

Question 4

what is the function of cholecystokinin

Answer 4

increase pancreatic enzyme secretion
increase gallbladder contraction
relaxation of sphincter of Oddi
decrease gastric emptying

Question 5

secretin is synthesized by what cells

Answer 5

S cells of intestines

Question 6

what is the function of secretin

Answer 6

increase bicarbonate secretion (secretin is released in response to low pH)
increase bile secretion
inhibit gastric acid secretion

Question 7

GIP (glucose dependent insulinotropic peptide) is secreted by what cells

Answer 7

K cells of intestine

Question 8

what is the function of GIP (glucose dependent insulinotropic peptide)

Answer 8

increase insulin release (GIP is released in response to lipid component of food intake)
decrease gastric acid secretion

Question 9

what is a property shared by both GIP and secretin

Answer 9

inhibition of gastric acid secretion

Question 10

motilin is secreted by what cells

Answer 10

Mo cells of intestines

Question 11

what is the function of motilin

Answer 11

controls interdigestive motor activity of GIT between meals

(the intestine has periods of rest moments between digestion periods because all that is being digested has been moved into the colon)

Question 12

what drug can act as a motilin agonist

Answer 12

erythromycin

Question 13

what is the function of ghrelin

Answer 13

stimulate growth hormone secretion
increase appetite
promote fat storage
inhibit insulin secretion

Question 14

what is the issue relating to GI hormones in Prader Willi syndrome

Answer 14

too high of plasma ghrelin levels causes increased hunger

Question 15

what is the ileal break

Answer 15

an inhibitory feedback mechanism to control movement through the GIT in order to optimize nutrient digestion and absorption

undigested nutrients (fats/lipid) which reach the ileum causes a negative feedback to slow movement through the GIT

Question 16

what hormones are secreted in cases of the ileal break inhibitory feedback mechanism

Answer 16

PYY, GLP-1, and oxyntomodulin by L cells in the ileum

Question 17

what is the importance of the liver in splanchnic circulation

Answer 17

the liver receives more blood from venous circulation via the portal vein than it receives fresh oxygenated blood from the hepatic artery

*all blood that passes through he GIT goes through the liver

Question 18

what are 3 reasons that explain an increase in blood flow during GI absorption

Answer 18

1. excess O2 used by mucosa–> increased adenosine and NO–> vasodilation
2. hyperosmolar intraluminal conditions–>increased intracellular Na+–> increased Ca2+–> activation of NO synthase–> increased NO–> vasodilation
3. other vasodilators in intestinal mucosa (ex: bradykinin, VIP, gastrin, secretin, CCK)