ADH controls water permeability of

Options

A. Collecting tube (distal part)
B. Proximal convoluted tubule
C. Distal convoluted tubule (distal part)
D. All the above

Answer

**Step-by-Step Solution:**

1. **Understanding ADH**: The first step is to recognize what ADH stands for. ADH is the abbreviation for Antidiuretic Hormone, which is also known as vasopressin.

2. **Source of ADH**: Next, we need to identify where ADH is produced. It is synthesized in the hypothalamus and released from the posterior pituitary gland.

3. **Function of ADH**: The primary function of ADH is to regulate water balance in the body by promoting water reabsorption in the kidneys. This is particularly important when the body is dehydrated or when there is a low fluid volume.

4. **Target Areas of ADH**: Now, we need to determine which part of the nephron ADH acts upon to control water permeability. The nephron is the functional unit of the kidney and consists of several parts, including the proximal convoluted tubule, loop of Henle, distal convoluted tubule (DCT), and collecting duct.

5. **Identifying the Correct Answer**: Among the options provided:
- Collecting tubule
- Proximal convoluted tubule
- Distal convoluted tubule
- Distal part
- All the above

The correct answer is the **distal convoluted tubule** (DCT) and also the collecting duct, as ADH primarily acts on these areas to increase water reabsorption. However, the most direct answer to the question is the distal convoluted tubule.

6. **Conclusion**: Therefore, the final answer to the question "ADH controls water permeability of" is the **distal convoluted tubule**.

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