The invaginations of cortex into medulla is called-

Options

A. Columns of Bertini
B. Duct of Bellini
C. Renal pelvis
D. Urethra

Answer

To answer the question, "The invaginations of cortex into medulla is called-", we can break down the solution into the following steps:

### Step-by-Step Solution:

1. **Understanding the Structure of the Kidney**:
- The kidney is composed of two main regions: the outer region known as the cortex and the inner region known as the medulla.

2. **Identifying the Medullary Pyramids**:
- The medulla is divided into conical structures called medullary pyramids. These pyramids are essential for the kidney's function.

3. **Recognizing the Role of the Cortex**:
- The cortex is the outer layer of the kidney and extends into the medulla.

4. **Defining the Invaginations**:
- The invaginations (or extensions) of the cortex that extend into the medulla are specifically referred to as renal columns.

5. **Correct Terminology**:
- The correct term for these invaginations of the cortex into the medulla is "columns of Bertini" (also known as renal columns).

6. **Conclusion**:
- Therefore, the answer to the question is that the invaginations of the cortex into the medulla are called **columns of Bertini**.

### Final Answer:
**Columns of Bertini**

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