Gastric Secretion

Question 1

What are the five secretory products of the stomach?

Answer 1

H, pepsinogens, water, mucus, intrinsic factor

Question 2

What two things do parietal cells makes?

Answer 2

IF and H

Question 3

What does the pyloric mucosa secrete?

Answer 3

Gastrin

Question 4

How does Carbonic Anyhydrase factor in H secretion?

Answer 4

It allows for the production of HCO3 which goes into the blood. To counteract this, Cl goes into the lumen, allowing the postive H to follow it.

Question 5

What two substances break down the gastric mucosal barrier?

Answer 5

aspirin and alcohol (aspirin is a weak acid)

Question 6

Into what structure is acid secreted within the parietal cell?

Answer 6

the intracellular canaliculi

Question 7

What disappear in the parietal cell when the cell is stimulated

Answer 7

tubulovesicles

Question 8

What ions are constant as H+ secretion increases?

Answer 8

Chloride

Question 9

What ion decreases drastically within the stomach as H secretion increases?

Answer 9

sodium

Question 10

Why does vomiting cause hypokalemia?

Answer 10

because the potassium levels in the stomach are higher than the body levels

Question 11

What are the three triggers to acid secretion?

Answer 11

Acetylcholine, gastin and histamine

Question 12

What is the chemical mediator of histamine in the stomach?

Answer 12

cAMP

Question 13

What triggers histamine release?

Answer 13

Gastrin releases histamine from the enterochromaffin-like cell (ECL cell)

Question 14

What is the chemical mediator of gastrin?

Answer 14

IP3

Question 15

What is the chemical mediator of ach?

Answer 15

ip3

Question 16

What is potentiation?

Answer 16

potentiation is the fact that the total acid released is higher than the inidivudal sums of each chemical . This occurs because each chemical triggers physiologic levels of secretion, but not max (so the three chemicals together increase production higher)

Question 17

What drug (and mechanism) interferes with potentiatoin?

Answer 17

cimetadine targets the histamine receptor

Question 18

When does gastrin secretion peak?

Answer 18

around midnight

Question 19

What causes increased amounts of gastrin secretion?

Answer 19

the more you like a food, the more food you eat.

Question 20

What percent gastrin secretion is based in the cephalic phase?

Answer 20

30%

Question 21

What are the two modulators of the vagal nervous system that allow for parietal cell stimultaion?

Answer 21

Ach (which directly targets parietal cells)

GRP

Question 22

In addition to the vagal fx that originate in the stomach, what else in the stomach causes increased acid secretion?

Answer 22

distension

Question 23

Ach from the vagus nerve works on which two types of cells to regulate gastrin release?

Answer 23

Gastrin cell (through GRP) (gastrin cells are also secreted through digested proteins)
Somatostatin cell (through Ach)

Question 24

What are the actions of somatostatin?

Answer 24

Somatostatin directly targets the parietal cell to reduce acid secretion. It also indirectly reduces levels by inhibiting gastrin secretion. The somatostatin cells are stimulated by elevation in H.

Question 25

Where does secretin come from and what does it do?

Answer 25

it comes from duodenum and decreases acid secretion.

Question 26

What are the two types of peptic ulcer disease?

Answer 26

gastric ulcer and duodenal ulcer

Question 27

Describe gastric ulcers

Answer 27

defective gastric mucosa
h. pylori
low rates of acid secretion
damage gastric mucosal barrier (nh4)

Question 28

describe duodenal ulcers

Answer 28

increased acid and pepsin
h pylori
increased gastrin levels, decresaed ability of somatostatin to inhibit gastrin, nh4
increased maximal acid secretion, increased parietal cellnumber