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

Options

A. Vasa recta are absent
B. Shorter loop of Henle
C. Fewer in number
D. Slower rate of filtration

Answer

To solve the question "Which of the following is not a feature of the cortical nephron?", we need to analyze the characteristics of cortical nephrons and compare them with the options provided.

### 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. **Identifying Cortical Nephrons**:
- Cortical nephrons are primarily located in the outer cortex of the kidney. They have a shorter loop of Henle compared to juxtamedullary nephrons, which extend deeper into the medulla.

3. **Analyzing Features of Cortical Nephrons**:
- **Vasa Recta**: This is a network of capillaries that is absent in cortical nephrons. It is primarily found in juxtamedullary nephrons.
- **Loop of Henle**: Cortical nephrons have a shorter loop of Henle compared to juxtamedullary nephrons.
- **Number of Nephrons**: Cortical nephrons are more numerous, constituting about 80% of all nephrons in the kidney, while juxtamedullary nephrons make up about 20%.
- **Rate of Filtration**: Cortical nephrons generally have a slower rate of filtration compared to juxtamedullary nephrons.

4. **Identifying the Incorrect Feature**:
- Based on the analysis:
- Vasa recta is absent in cortical nephrons (True).
- They have a shorter loop of Henle (True).
- They are fewer in number (False, as they are more numerous).
- They have a slower rate of filtration (True).

5. **Conclusion**:
- The feature that is **not** characteristic of cortical nephrons is that they are "fewer in number". Therefore, the correct answer is the option stating that cortical nephrons are fewer in number.

### Final Answer:
The feature that is not characteristic of cortical nephrons is that they are "fewer in number".