Main site for reabsorption and tubular secretion nephron is

Options

A. PCT
B. DCT
C. Henle's loop
D. Both (1) and (2)

Answer

To answer the question regarding the main site for reabsorption and tubular secretion in the nephron, we can follow these steps:

### Step-by-Step Solution:

1. **Understanding the Nephron Structure**:
- The nephron is the functional unit of the kidney and consists of two main parts: the glomerulus (where filtration occurs) and the renal tubule (where reabsorption and secretion take place).

2. **Identifying the Renal Tubule Components**:
- The renal tubule is divided into several segments:
- Proximal Convoluted Tubule (PCT)
- Loop of Henle
- Distal Convoluted Tubule (DCT)
- Collecting Duct

3. **Function of the Proximal Convoluted Tubule (PCT)**:
- The PCT is the first segment of the renal tubule and is primarily responsible for the reabsorption of a significant portion of the filtrate.
- Approximately 70-80% of electrolytes and other essential substances are reabsorbed here.

4. **Secretion in the PCT**:
- In addition to reabsorption, the PCT also plays a crucial role in the secretion of substances such as hydrogen ions, ammonia, and potassium ions.

5. **Conclusion**:
- Given the functions and importance of the PCT in reabsorption and secretion, it is identified as the main site for these processes in the nephron.

### Final Answer:
The main site for reabsorption and tubular secretion in the nephron is the **Proximal Convoluted Tubule (PCT)**.

---