Which of the following part is diluting segment in human nephron ?

Options

A. Descending limb of lop of henel
B. Proximal convoluted tubule
C. Ascending limb of loop of Henle
D. None of these

Answer

To determine which part of the human nephron is the diluting segment, we can analyze the options provided:

1. **Descending Limb of Loop of Henle**:
- This segment is highly permeable to water. As a result, water is reabsorbed here, which does not contribute to dilution. Therefore, this option is incorrect.

2. **Proximal Convoluted Tubule**:
- The proximal convoluted tubule is primarily responsible for the reabsorption of nutrients, ions, and water. It is not specifically involved in diluting the filtrate. Thus, this option is also incorrect.

3. **Ascending Limb of Loop of Henle**:
- The ascending limb is impermeable to water and actively transports ions (like sodium and chloride) out of the tubule. This process reduces the osmolarity of the fluid inside the nephron, effectively diluting it. Therefore, this is the correct answer.

4. **None of These**:
- Since we have identified the ascending limb as the diluting segment, this option is incorrect.

Based on the analysis, the correct answer is the **Ascending Limb of Loop of Henle**.

### Step-by-Step Solution:
1. **Identify the Options**: Review the given options related to the nephron segments.
2. **Analyze Each Option**:
- Check the function of the **Descending Limb** (water permeable, not diluting).
- Check the function of the **Proximal Convoluted Tubule** (main site for reabsorption, not diluting).
- Check the function of the **Ascending Limb** (impermeable to water, actively transports ions, dilutes fluid).
- Consider the option **None of These** (incorrect since we have a valid answer).
3. **Select the Correct Answer**: Conclude that the **Ascending Limb of Loop of Henle** is the diluting segment.