Counter current flow of blood found in the two limbs of `"______"`

Options

A. DL of Henel's loop
B. Al fo Henle's loop
C. Vasa reacta
D. Vasa varicosa

Answer

**Step-by-Step Solution:**

1. **Understanding the Question**: The question asks about the location of the counter-current flow of blood. We need to identify which structure in the kidney exhibits this mechanism.

2. **Defining Counter Current Flow**: Counter current flow refers to the movement of fluids in opposite directions. In the context of the kidneys, this mechanism is crucial for concentrating urine and maintaining osmolarity.

3. **Identifying the Structures Involved**: In the kidney, the two main structures that are involved in the counter current mechanism are the Loop of Henle (which consists of descending and ascending limbs) and the Vasa Recta.

4. **Analyzing the Loop of Henle**:
- The **Descending Loop of Henle** primarily reabsorbs water but does not contribute to counter current blood flow.
- The **Ascending Loop of Henle** reabsorbs NaCl but also does not have a counter current blood flow.

5. **Examining the Vasa Recta**: The Vasa Recta are the capillaries that surround the Loop of Henle and are responsible for maintaining the osmotic gradient in the kidney. They exhibit counter current flow, which is essential for the concentration of urine.

6. **Conclusion**: Based on the analysis, the correct answer to the question is that the counter current flow of blood is found in the two limbs of the **Vasa Recta**.

**Final Answer**: Vasa Recta

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