Which of the following statements is not correct for most common type of nephrons of human kidney ?

Options

A. They are small size, less coiled with major part present at the junction of cortex and medulla.
B. They have short length of loop of Henle.
C. They do not have major role to from counter current mechanism.
D. They have no or highly reduced vasa recta.

Answer

To solve the question regarding which statement is not correct for the most common type of nephrons in the human kidney, we will follow these steps:

### Step-by-Step Solution:

1. **Identify the Types of Nephrons**:
- There are two main types of nephrons in the human kidney: cortical nephrons and juxtamedullary nephrons.
- Cortical nephrons are the most common type, while juxtamedullary nephrons are less common.

2. **Characteristics of Cortical Nephrons**:
- Cortical nephrons have a short loop of Henle (LOH) that extends only slightly into the medulla.
- They are primarily located in the cortex of the kidney and do not extend deep into the medulla.

3. **Evaluate the Statements**:
- We need to evaluate the provided statements about cortical nephrons to identify which one is incorrect.
- Common characteristics of cortical nephrons include:
- They are small in size.
- They have a short loop of Henle.
- They do not play a major role in the countercurrent mechanism due to the reduced presence of the vasa recta.

4. **Identify the Incorrect Statement**:
- The statement that says "major portion present at the junction of cortex and medulla" is incorrect.
- Cortical nephrons are primarily located in the cortex and do not significantly extend into the medulla.

5. **Conclusion**:
- The statement that is not correct for the most common type of nephrons (cortical nephrons) is that they are located at the junction of the cortex and medulla.

### Final Answer:
The incorrect statement regarding the most common type of nephrons in the human kidney is: "major portion present at the junction of cortex and medulla."

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