Mechanism of Gastric acid secretion

Match the following gastric exocrine cells with its secretion:

• HCl and intrinsic factor

• Parietal cells

• Pepsinogen

• Mucous cells

• Alkaline mucous

• Chief cells

Match the following gastric endocrine cells with its secretion:

• Somatostatin

• G cells

• Gastrin

• ECL cells

• Histamine

• D cells

From the lecture, describe the direct pathway in stimulating the parietal cells for acid secretion.

Answer explanation

Acetylcholine (via muscarinic receptor, gastrin (via gastrin receptors) and histamine (via histamine receptor) stimulate the parietal cells.

Describe the indirect pathway of stimulating parietal cells to secrete acid.

Answer explanation

Acetylcholine and gastrin stimulate ECL cell to release histamine. Histamine acts on parietal cells.

a

b

c

d

H2CO3 dissociates to HCO3- and H+

HCO-3 going out for Cl- coming in

CO2 from blood stream diffuses in

CA catalyze to form H2CO3

Match to the correct order

a

b

c

d

H+-K+ATPase, cotransports K+

net result is formation of HCl

Cl- also passes through

H+ driven out.