Which of the following is not a feature of cortical nephros?

Options

A. These are more common, approximately `85%` of nephrons
B. Their glomeruli are in outer cortex
C. Their loop of Henle extend to a short distance into the medulla
D. They are associated with vasa recta

Answer

To determine which of the following is not a feature of cortical nephrons, let's analyze the characteristics of cortical nephrons 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 medullary nephrons.

2. **Cortical Nephrons**:
- **Percentage**: Approximately 85% of the nephrons in the kidney are cortical nephrons.
- **Location of Glomeruli**: The glomeruli of cortical nephrons are located in the outer cortex of the kidney.
- **Loop of Henle**: The loop of Henle in cortical nephrons extends only a short distance into the medulla, meaning it does not penetrate deeply into the inner medullary region.

3. **Association with Vasa Recta**:
- Cortical nephrons are not associated with the vasa recta, which are blood vessels that supply the nephron and are more closely associated with medullary nephrons. Medullary nephrons have longer loops of Henle that extend deep into the medulla and are closely associated with the vasa recta.

4. **Evaluating the Options**:
- **Option 1**: "They are approximately 85% of the nephrons" - This is true for cortical nephrons.
- **Option 2**: "Their glomeruli occur in the outer cortex" - This is also true.
- **Option 3**: "Their loop of Henle extends into a shorter distance into the medulla" - This statement is true as well.
- **Option 4**: "They are associated with the vasa recta" - This statement is false because cortical nephrons are not associated with the vasa recta; this feature is characteristic of medullary nephrons.

### Conclusion:
The statement that is **not a feature of cortical nephrons** is: **"They are associated with the vasa recta."**

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