Extensions of cortex in between renal medullary pyramids are known as

Options

A. Columns of Bertini
B. Ducts of Bellini
C. Collecting ducts
D. Juxta glomerular apparatus

Answer

To solve the question, "Extensions of cortex in between renal medullary pyramids are known as," we can follow these steps:

### Step-by-Step Solution:

1. **Understand the Anatomy of the Kidney**:
- The kidney is divided into two main regions: the outer region known as the cortex and the inner region known as the medulla.

2. **Identify the Structure in Question**:
- The question specifically asks about the extensions of the cortex that are found between the renal medullary pyramids.

3. **Recognize the Medullary Pyramids**:
- The renal medullary pyramids are conical structures located within the medulla of the kidney. They are important for the kidney's function in urine formation.

4. **Identify the Extensions of Cortex**:
- The extensions of the cortex that project between the medullary pyramids are known as the "columns of Bertini" (also referred to as renal columns).

5. **Review the Options Provided**:
- Option A: Columns of Bertini
- Option B: Ducts of Bellini
- Option C: Collecting duct
- Option D: Juxtaglomerular apparatus (JGA)

6. **Eliminate Incorrect Options**:
- Ducts of Bellini and collecting ducts are structures involved in urine collection and concentration but do not refer to the extensions of the cortex.
- The Juxtaglomerular apparatus is involved in blood pressure regulation and does not relate to the cortex extensions.

7. **Conclude the Correct Answer**:
- Based on the understanding of kidney anatomy, the correct answer is **Option A: Columns of Bertini**.

### Final Answer:
The extensions of cortex in between renal medullary pyramids are known as **Columns of Bertini**.

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