The first site for observing chyme in the human gut is

Options

A. buccal cavity
B. duodenum
C. stomach
D. colon

Answer

To determine the first site for observing chyme in the human gut, we can follow these steps:

### Step-by-Step Solution:

1. **Understanding Digestion**: Digestion is the process of breaking down complex food substances into simpler forms that can be absorbed by the body. This process begins in the mouth.

**Hint**: Recall the definition of digestion and where it starts in the human body.

2. **Role of the Buccal Cavity**: In the buccal cavity (mouth), food is mechanically broken down by chewing and mixed with saliva, which contains enzymes that begin the chemical digestion of carbohydrates. The resulting mass is called a bolus.

**Hint**: Think about what happens to food in the mouth and the term used for the mass formed after chewing.

3. **Movement to the Stomach**: After swallowing, the bolus travels down the esophagus and enters the stomach. In the stomach, the acidic environment and enzymes (like pepsin) further digest the food, particularly proteins.

**Hint**: Consider what happens to the bolus when it reaches the stomach and what enzymes are involved.

4. **Formation of Chyme**: In the stomach, after the food is digested, the bolus transforms into a semi-liquid substance known as chyme. This is the first point in the digestive process where chyme is formed.

**Hint**: Identify the term used for the mixture of partially digested food and digestive juices in the stomach.

5. **Chyme in the Digestive Process**: After the stomach, chyme moves into the small intestine, specifically the duodenum, where further digestion occurs. However, the question specifically asks for the first site where chyme is observed.

**Hint**: Focus on the definition of chyme and where it is first produced in the digestive tract.

6. **Conclusion**: The first site for observing chyme in the human gut is the stomach, where the bolus is converted into chyme.

**Final Answer**: The correct option is **stomach**.

### Summary of Steps:
- Understand digestion and its starting point.
- Identify the role of the buccal cavity.
- Recognize the transition from bolus to chyme in the stomach.
- Conclude that the first observation of chyme occurs in the stomach.