Which of the following cannot be considered as a point of difference between cortical and juxtamedullary nephrons?

Options

A. Their number
B. Length of loop of Henle
C. Presence of vasa recta
D. Presence of peritubular capillaries

Answer

To determine which of the following cannot be considered a point of difference between cortical and juxtamedullary nephrons, we need to analyze each option provided:

1. **Number of Nephrons**:
- In humans, approximately 85% of nephrons are cortical nephrons, while only about 15% are juxtamedullary nephrons.
- This indicates a clear difference in their numbers.

2. **Length of Loop of Henle**:
- The loop of Henle in cortical nephrons is relatively short, while in juxtamedullary nephrons, it is much longer.
- This is another significant point of difference.

3. **Presence of Vasa Recta**:
- Vasa recta are long, straight capillaries that are associated with the juxtamedullary nephrons and are involved in the concentration of urine.
- Cortical nephrons have a smaller vasa recta.
- Thus, this is also a point of difference.

4. **Presence of Peritubular Capillaries**:
- Peritubular capillaries are tiny blood vessels that surround the nephron and are involved in reabsorption and secretion.
- These capillaries are present in both cortical and juxtamedullary nephrons.
- Therefore, this option does not represent a point of difference between the two types of nephrons.

Based on this analysis, the option that cannot be considered a point of difference between cortical and juxtamedullary nephrons is **the presence of peritubular capillaries**.

**Final Answer**: Presence of peritubular capillaries.

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