gastric secretions

Question 1

which cells secrete HCl

Answer 1

parietal cells

Question 2

how are parietal cells stimulated (what receptor, what neurotransmitter)

Answer 2

Ach M3 receptor (think parasympathetic)

Question 3

what do parietal cells secrete other than HCl

Answer 3

intrinsic factor

Question 4

what is gastrin

Answer 4

released from G cellsbinds to cholecystokinin receptors on parietal cells, activates H+ ATPase pump

Question 5

what do chief cells release

Answer 5

pepsinogen

Question 6

what is pepsinogen

Answer 6

zymogen of pepsin

Question 7

how is pepsinogen activated

Answer 7

acidic environment

Question 8

what stimulates pepsinogen release

Answer 8

vagus activation Ach release, NO, secretin, gastrin

Question 9

what do ECL secrete, how are they stimiulated, what do they do

Answer 9

histamine, ach from vagus, histamine binds to H2 receptor on parietal cells -> HCl released into the lumen of the stomach

Question 10

what is the top neck of the stomach called

Answer 10

cardia

Question 11

what is the area where the gastric bubble is called

Answer 11

fundus

Question 12

where are the majority of D and G cells

Answer 12

antrum

Question 13

what is the bit just before the exit sphincter of the stomach called

Answer 13

pylorus

Question 14

mechanisms of somatostatin inhibition (3)

Answer 14

block histamine action on parietal cells
binds to ECL to stop histamine release
binds to G cells to inhibit gastrin release

Question 15

what triggers somatostatin release

Answer 15

low pH in anrtum

Question 16

how do prostaglandins inhibit acid

Answer 16

bind to PG receptors on parietal cells
stimulate mucus cells so more muucs -> more HCO3

Question 17

explain NSAID and aspirin damage

Answer 17

inhibit prostaglandin production -> less mucus via COX pathway -> lowered pH and thinner mucus

Question 18

what is Zollinger Ellison syndrome?

Answer 18

gastrinoma -> ++gastrin-> ++HCl -> many ulcers

Question 19

what is the role of paneth cells

Answer 19

mostly controlling the microbiota of teh intestine

Question 20

where do you find paneth cells. what do they look like histologically

Answer 20

bottom of crypts of lieberkuhn
columnar with eosinophilic granules

Question 21

describe S cells

Answer 21

in the small intestine crypts of lieberkuhn
secrete secretin into the bloodstream

Question 22

what does secretin do

Answer 22

raise pH of chyme when it enters duodenum
inhibits gastrin
stimulates HCO3 release from pancreas by increasing activity of HCO3 Cl- exchanger