Parietal cells of mucosa in stomach in secrets:

Options

A. Mucin
B. Pepsin
C. Dilute HCI
D. All of these

Answer

### Step-by-Step Solution:

1. **Identify the Cells in the Stomach**: The stomach contains different types of exocrine gland cells, including mucous neck cells, parietal cells, and chief cells.

2. **Understand the Function of Parietal Cells**: Parietal cells are specifically responsible for the secretion of certain substances in the stomach.

3. **List the Secretions of Parietal Cells**:
- **Hydrochloric Acid (HCl)**: This is a strong acid that aids in digestion by creating an acidic environment in the stomach, which is necessary for the activation of digestive enzymes.
- **Intrinsic Factor**: This is a glycoprotein that is crucial for the absorption of vitamin B12 in the intestines.

4. **Evaluate the Options Given in the Question**:
- Option 1: Mucin - This is secreted by mucous neck cells, not parietal cells. **(Incorrect)**
- Option 2: Pepsin - This enzyme is secreted as pepsinogen by chief cells, not parietal cells. **(Incorrect)**
- Option 3: Dilute HCl - While parietal cells secrete hydrochloric acid, it is not typically referred to as "dilute HCl." However, this option is the closest to being correct. **(Correct)**
- Option 4: Parietal cells of mucosa in stomach secrete dilute HCl - This is the most accurate description of what parietal cells secrete. **(Correct)**

5. **Conclusion**: The parietal cells of the stomach mucosa secrete hydrochloric acid (HCl) and intrinsic factor, making the correct answer related to their secretion of HCl.