Which of the following is not correct ?

Options

A. The blood vessel leading to the glomerulus is called the afferent arteriole.
B. Juxtamedullary nephrons, peritubular capillaries and Bowman's capsule all lie in the cortical region of the kidney .
C. Cortical nephrons have no or highly reduced vasa recta .
D. Vasa recta run parallel to the Henle's loop in juxtamedullary nephrons but the flow of blood inside them is in the opposite direction .

Answer

To solve the question "Which of the following is not correct?", let's analyze each statement step by step.

### Step 1: Analyze the First Statement
**Statement:** The blood vessel leading to the glomerulus is called the efferent arteriole.

**Analysis:**
- The blood vessel that brings blood to the glomerulus is called the **afferent arteriole**, not the efferent arteriole. The efferent arteriole carries blood away from the glomerulus.
- **Conclusion:** This statement is **incorrect**.

### Step 2: Analyze the Second Statement
**Statement:** Juxtamedullary nephrons, peritubular capillaries, and Bowman's capsule all lie in the cortical region of the kidney.

**Analysis:**
- Juxtamedullary nephrons have their glomeruli located near the border of the cortex and medulla, and their long loops of Henle extend deep into the medulla.
- Peritubular capillaries surround the nephron tubules and are primarily located in the cortical region.
- **Conclusion:** This statement is **incorrect** because juxtamedullary nephrons extend into the medulla.

### Step 3: Analyze the Third Statement
**Statement:** Cortical nephrons have no or highly reduced vasa recta.

**Analysis:**
- Cortical nephrons are primarily located in the cortex and do not have vasa recta, or they have it in a highly reduced form.
- **Conclusion:** This statement is **correct**.

### Step 4: Analyze the Fourth Statement
**Statement:** Vasa recta run parallel to the loop of Henle in juxtamedullary nephrons, but the flow of blood inside them is in the opposite direction.

**Analysis:**
- Vasa recta are indeed associated with juxtamedullary nephrons and run parallel to the loop of Henle. The blood flow in the vasa recta is countercurrent to the flow in the loop of Henle.
- **Conclusion:** This statement is **correct**.

### Final Conclusion
After analyzing all the statements, the one that is not correct is the **second statement** regarding the location of juxtamedullary nephrons, peritubular capillaries, and Bowman's capsule.

### Answer
The incorrect statement is: **Juxtamedullary nephrons, peritubular capillaries, and Bowman's capsule all lie in the cortical region of the kidney.**

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