In which part of uriniferous tubule, `Na^(+)` passes out

Options

A. Descending loop of Henle
B. collecting tubule
C. Ascending loop of Henle
D. None of the above

Answer

To determine where Na⁺ (sodium ions) passes out in the uriniferous tubule, we can follow these steps:

### Step-by-Step Solution:

1. **Understand the Structure of the Nephron**:
- The nephron is the functional unit of the kidney and consists of several parts, including the glomerulus, Bowman's capsule, proximal convoluted tubule, loop of Henle (which includes the descending and ascending loops), distal convoluted tubule, and collecting duct.

2. **Identify the Function of Each Part**:
- Each part of the nephron has specific functions related to filtration, reabsorption, and secretion of various substances, including ions like Na⁺.

3. **Focus on the Loop of Henle**:
- The loop of Henle is divided into two segments: the descending loop and the ascending loop.
- The descending loop is primarily permeable to water and does not actively transport Na⁺.
- The ascending loop, on the other hand, is impermeable to water but actively transports Na⁺ out of the tubular fluid.

4. **Determine the Correct Answer**:
- Since the question asks where Na⁺ passes out, we focus on the ascending loop of Henle, where Na⁺ is actively reabsorbed into the interstitial fluid, thus passing out of the tubular fluid.

5. **Conclusion**:
- Therefore, the correct answer to the question is **C: ascending loop of Henle**.