Main function of loop of Henle is to cause

Options

A. Absorption of water
B. Absorption of sugar
C. Absorption of sodium
D. Secretion of ions

Answer

### Step-by-Step Solution:

1. **Understanding the Loop of Henle**: The Loop of Henle is a U-shaped portion of the nephron in the kidney that plays a crucial role in the concentration of urine.

2. **Analyzing the Options**:
- **Option 1: Absorption of Water**: The primary function of the Loop of Henle is to facilitate the reabsorption of water. The descending limb of the loop is permeable to water but not to ions, allowing water to exit into the surrounding hypertonic tissue fluid, which is rich in ions.
- **Option 2: Absorption of Sugar**: This is incorrect as the absorption of sugars primarily occurs in the proximal convoluted tubule, not in the Loop of Henle.
- **Option 3: Absorption of Sodium**: This is also incorrect. While sodium is reabsorbed in the nephron, about 65% of sodium reabsorption occurs in the proximal convoluted tubule, not in the Loop of Henle.
- **Option 4: Secretion of Ions**: This option is incorrect as well. The secretion of ions occurs in various parts of the nephron, but the Loop of Henle is not primarily responsible for this function.

3. **Conclusion**: Based on the analysis, the main function of the Loop of Henle is indeed the absorption of water, leading to the production of more concentrated filtrate.

### Final Answer:
The main function of the Loop of Henle is to cause the absorption of water.

---