Which of the following is incorrect about juxta medullary nephrons?
(a) Vasa recta is prominent
(b) `Na^(+)` is returned to the interstitium by ascending limb of vasa recta
(c) Water is returned in the ascending limb of Henle
(d) Loop of Henle is long

Options

A. Vasa recta is prominent
B. `Na^(+)` is returned to the interstitium by ascending limb of vasa recta
C. Water is returned in the ascending limb of Henle
D. Loop of Henle is long

Answer

To determine which statement is incorrect about juxtamedullary nephrons, let's analyze each option step by step.

### Step 1: Understanding Juxtamedullary Nephrons
Juxtamedullary nephrons are a type of nephron located at the junction of the renal cortex and medulla. They are characterized by their long loops of Henle, which extend deep into the medulla.

### Step 2: Analyzing Each Option
- **(a) Vasa recta is prominent**: This statement is **correct**. In juxtamedullary nephrons, the vasa recta (the capillary network that supplies blood to the medulla) is indeed more prominent compared to cortical nephrons.

- **(b) Na⁺ is returned to the interstitium by ascending limb of vasa recta**: This statement is also **correct**. The ascending limb of the vasa recta plays a role in the countercurrent exchange mechanism, returning sodium ions to the interstitium.

- **(c) Water is returned in the ascending limb of Henle**: This statement is **incorrect**. The ascending limb of the loop of Henle is impermeable to water, meaning that water cannot be reabsorbed in this segment.

- **(d) Loop of Henle is long**: This statement is **correct**. Juxtamedullary nephrons have long loops of Henle, which are essential for concentrating urine.

### Conclusion
The incorrect statement about juxtamedullary nephrons is **(c) Water is returned in the ascending limb of Henle**.

### Final Answer
The incorrect statement is **(c)**.

---