Question

Which of the following is the primary site of production of Gastrin?

• A. Pylorus
• B. Antrum
• C. Pancreas
• D. Small intestine

Hint:

Think of the G cells located in the lower stomach lining.

Answer 1

The Correct Option is B

Step 1: Understanding the Question:
We need to identify where in the gastrointestinal tract the hormone gastrin is mainly produced.

Step 2: Key Formula or Approach:
Gastrin is made by specific hormone secreting cells, called G cells, and these cells are concentrated in one particular region of the stomach's lining.

Step 3: Detailed Explanation:
The G cells that secrete gastrin are found predominantly in the mucosa of the gastric antrum, the lower part of the stomach nearest the pylorus, where they respond to stomach distension, peptides, and vagal stimulation by releasing gastrin into the bloodstream. Gastrin then travels back to stimulate acid secretion from parietal cells higher up in the stomach.
The pylorus itself is the muscular valve at the end of the antrum and is not the main site of gastrin producing cells, even though it lies close to the antrum.
The pancreas produces its own set of hormones, such as insulin and glucagon, but it is not the primary source of gastrin.
The small intestine contains various other gut hormone producing cells, such as those making secretin and cholecystokinin, but gastrin production there is minimal compared to the antrum.

Step 4: Final Answer:
So the primary site of gastrin production is the antrum of the stomach.