Where does the digestion of proteins start in the human body?

Options

A. Mouth
B. Stomach
C. Liver
D. Small intestine

Answer

### Step-by-Step Solution:

1. **Understanding Digestion**: Digestion is the process of breaking down food into smaller components that can be absorbed by the body. It involves both mechanical and chemical processes.

2. **Elementary Canal**: The digestion of food occurs in the elementary canal, which is a long tube that starts from the mouth and ends at the anus.

3. **Mouth (Bucal Cavity)**: The first part of the elementary canal is the buccal cavity (mouth), where food enters. Here, salivary glands secrete saliva, which contains the enzyme amylase that begins the digestion of carbohydrates, not proteins.

4. **Esophagus**: After the mouth, food travels down the esophagus. The esophagus primarily functions to transport food to the stomach and does not contribute to protein digestion.

5. **Stomach**: The food then enters the stomach, where the digestion of proteins begins. The stomach contains gastric glands that secrete gastric juices, which have a low pH. This acidic environment activates proteolytic enzymes such as pepsin, which start breaking down proteins into smaller peptides.

6. **Small Intestine**: Although the stomach initiates protein digestion, the complete digestion of proteins occurs in the small intestine. Here, additional enzymes from the pancreas and bile from the liver further break down the peptides into amino acids.

7. **Conclusion**: Therefore, the digestion of proteins starts in the stomach.

### Final Answer:
The digestion of proteins starts in the stomach.

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