Read the following statements and select the correct option
Statement 1 : When the urine moves through the descending limb, it becomes hypertonic to blood plasma and as it passes through the ascending limb of Henl's loop it becomes hypotonic to blood plasma
Statement : The decending limb is permeable to sodium ions, while the ascending limb is impermeable to sodium ions

Options

A. Both statement 1 and 2 are correct and statement 2 is the correct explanation of statement 1
B. Both statements 1 and 2 are correct but statement 2 is not the correct explanation of statement 1
C. Statement 1 is correct but statement 2 is incorrect
D. Both statements 1 and 2 are incorrect

Answer

To analyze the given statements, we will break down the information provided in each statement regarding the loop of Henle in the nephron of the kidney.

### Step-by-Step Solution:

1. **Understanding Statement 1**:
- **Statement 1**: "When the urine moves through the descending limb, it becomes hypertonic to blood plasma and as it passes through the ascending limb of Henle's loop it becomes hypotonic to blood plasma."
- The descending limb of the loop of Henle is permeable to water but not to solutes. As urine (filtrate) moves down this limb, water is reabsorbed into the surrounding interstitial fluid, leading to an increase in solute concentration in the filtrate. Therefore, the filtrate becomes hypertonic compared to blood plasma.
- As the filtrate moves into the ascending limb, which is impermeable to water but permeable to sodium and other ions, sodium is reabsorbed, causing the filtrate to lose solutes and become hypotonic compared to blood plasma.

2. **Understanding Statement 2**:
- **Statement 2**: "The descending limb is permeable to sodium ions, while the ascending limb is impermeable to sodium ions."
- This statement is incorrect. The descending limb is not permeable to sodium ions; it is primarily permeable to water. The ascending limb, on the other hand, is permeable to sodium ions (and other solutes) but impermeable to water.

3. **Conclusion**:
- Based on the analysis, Statement 1 is correct, while Statement 2 is incorrect.

### Final Answer:
- The correct option is that Statement 1 is true and Statement 2 is false.