Question

1. ____________________________ What hormone secreted by the stomach also is a primary stimulant of stomach action, secretion & motility?

2. __________________________ What hormone’s release is primarily stimulated by a drop in pH in the small intestines?

3. What is a proton pump and what does the stomach use it for?

Answer 1

First question.

It's gastrin. It is a peptide hormone. It activates the parietal cells to produce gastric acid. At the same time it also protects the stomach during gastric motility. So thus it becomes the primary stimulant of stomach action.

Second question.

It's secretin. When the gastric acid reaches the deuodenum makes the release of secretin. We know gastric acid has a low pH. So this is released in response to the acidity condition in small intestine.

Third question.

Proton pump is an integral membrane protein on the parietal cells. It pumps proton into the stomach in replacement of potassium ions. It uses ATP for this function. Stomach required e this pump for providing the acidic situation inside it by releasing HCL. The antiport system transport cl- ions to parietal cells from blood in return to the pumping of HCO3- to blood. This cl- reaches the stomach. For the H+ ions to reach stomach it needs a proton pump