Two counter -current systems formed in the kidney are by the _____and the __________.

Answer

**Step-by-Step Solution:**

1. **Understanding the Question**: The question asks for the two counter-current systems formed in the kidney.

2. **Identifying the Structures in the Kidney**: The kidney is composed of various structures that play a role in filtration and urine formation. Among these structures, the Loop of Henle and the Vasa Recta are significant.

3. **Defining Counter-Current Systems**: A counter-current system is characterized by the flow of fluids in opposite directions. This mechanism is crucial for the kidney's ability to concentrate urine and conserve water.

4. **Identifying the First Counter-Current System**: The Loop of Henle is the first structure that exhibits a counter-current mechanism. It consists of two limbs (ascending and descending) where the filtrate flows in opposite directions.

5. **Identifying the Second Counter-Current System**: The Vasa Recta is the second structure that forms a counter-current system. It runs parallel to the Loop of Henle and also has two limbs where blood flows in opposite directions.

6. **Conclusion**: Therefore, the two counter-current systems formed in the kidney are by the **Loop of Henle** and the **Vasa Recta**.

**Final Answer**: The two counter-current systems formed in the kidney are by the **Loop of Henle** and the **Vasa Recta**.

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