Which of the following function or activity is not affected by smooth muscles in human ?

Options

A. Transportation of food through the digestive tract
B. Transport of gametes through the genital duct
C. Transportation of urine through the ureter and bladder
D. Chewing and swallowing of food through buccal cavity .

Answer

To solve the question regarding which function or activity is not affected by smooth muscles in humans, we can analyze each option provided.

### Step-by-Step Solution:

1. **Understanding Smooth Muscles**: Smooth muscles are involuntary muscles found in various organs such as the digestive tract, blood vessels, and reproductive organs. They are responsible for various automatic functions in the body.

2. **Analyzing Option 1**:
- **Transportation of food through the digestive tract**: This process involves peristalsis, which is the contraction of smooth muscles in the walls of the digestive tract. Therefore, smooth muscles are indeed involved in this function.
- **Conclusion**: This option is affected by smooth muscles.

3. **Analyzing Option 2**:
- **Transport of gametes through the genital duct**: In females, the smooth muscles in the uterus and fallopian tubes help in the movement of gametes (sperm and ovum). Thus, smooth muscles play a role in this activity.
- **Conclusion**: This option is affected by smooth muscles.

4. **Analyzing Option 3**:
- **Transport of urine through the ureter and bladder**: The smooth muscles in the ureters and bladder facilitate the movement of urine. Therefore, this function is also influenced by smooth muscles.
- **Conclusion**: This option is affected by smooth muscles.

5. **Analyzing Option 4**:
- **Swinging and swallowing of water through the buccal cavity**: This process primarily involves skeletal muscles, particularly those in the mouth and throat, rather than smooth muscles. Smooth muscles do not play a significant role in this activity.
- **Conclusion**: This option is NOT affected by smooth muscles.

### Final Answer:
The function or activity that is not affected by smooth muscles in humans is **Option 4: Swinging and swallowing of water through the buccal cavity**.

---