Which of the following statement is not true about nephrons ?

Options

A. Cortical nephrons are more common.
B. Cortical nephrons lack vasa recta
C. In Juxta medullary nephrons, the blood first passes through vasa recta and then through the capillaries of glomerulus.
D. The glomeruli of Juxta medullary nephrons are placed close to the junction of cortex and medulla.

Answer

To determine which statement is not true about nephrons, let's analyze each statement step by step.

### Step-by-Step Solution:

1. **Understanding Nephrons**:
- Nephrons are the functional units of the kidney responsible for filtering blood and forming urine. There are two main types of nephrons: cortical nephrons and juxtamedullary nephrons.

2. **Evaluating Statement A**:
- **Statement A**: "Cortical nephrons are more common."
- **Analysis**: Cortical nephrons are indeed more numerous, making this statement true.

3. **Evaluating Statement B**:
- **Statement B**: "Cortical nephrons lack vasa recta."
- **Analysis**: This statement is also true because vasa recta are associated with juxtamedullary nephrons, not cortical nephrons.

4. **Evaluating Statement C**:
- **Statement C**: "In juxtamedullary nephrons, the blood first passes through vasa recta and then through the capillaries of glomerulus."
- **Analysis**: This statement is incorrect. In juxtamedullary nephrons, blood first enters the glomerulus for filtration before it moves to the vasa recta. Therefore, this statement is false.

5. **Conclusion**:
- The statement that is not true about nephrons is **Statement C**.

### Final Answer:
The incorrect statement about nephrons is **Statement C**: "In juxtamedullary nephrons, the blood first passes through vasa recta and then through the capillaries of glomerulus."

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