Gastrin and secretin are separated respectively by :

Options

A. Stomach and small intestine
B. Stomach and stomach
C. Small intestine and small intestine
D. Small intestine and stomach

Answer

To solve the question "Gastrin and secretin are separated respectively by:", we need to identify where each hormone is secreted in the gastrointestinal tract.

### Step-by-Step Solution:

1. **Identify the Source of Gastrin**:
- Gastrin is a hormone that is secreted by the gastric glands located in the stomach. Its primary function is to stimulate the secretion of hydrochloric acid and pepsinogen, which are essential for digestion in the stomach.

2. **Identify the Source of Secretin**:
- Secretin is a hormone that is secreted by the S cells in the duodenum, which is the first part of the small intestine. Secretin plays a crucial role in regulating the pH of the small intestine by stimulating the pancreas to secrete bicarbonate, which neutralizes stomach acid.

3. **Determine the Separation**:
- Since Gastrin is secreted from the stomach and Secretin is secreted from the small intestine, we can conclude that these two hormones are separated by the stomach and the small intestine.

4. **Review the Options**:
- The options given in the question are:
- Stomach and small intestine
- Stomach and stomach
- Small intestine and small intestine
- Small intestine and stomach
- Based on our analysis, the correct answer is "stomach and small intestine".

### Final Answer:
Gastrin and secretin are separated respectively by the stomach and small intestine.

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