The juxtaglomerular cells of the _______ and the macula densa cells of the _____ form the juxta-glomerular apparatus.

Options

A. afferent arteriole, proximal convoluted tubule
B. efferent arteriole, proximal convoluted tubule
C. afferent arteriole, distal convoluted tubule
D. vasa recta, distal convoluted tubule

Answer

To solve the question, we need to identify the specific cells that make up the juxtaglomerular apparatus (JGA) in the kidney.

### Step-by-Step Solution:

1. **Understanding the Juxtaglomerular Apparatus (JGA)**:
- The JGA is a structure in the kidney that plays a crucial role in regulating blood pressure and the filtration rate of the glomerulus.

2. **Identifying the Components of JGA**:
- The JGA is composed of two main types of cells:
- **Juxtaglomerular (JG) cells**: These are specialized smooth muscle cells that are located in the walls of the afferent arteriole.
- **Macula densa cells**: These are specialized cells located in the distal convoluted tubule (DCT) that sense sodium concentration.

3. **Analyzing the Options**:
- We need to match the cells with their respective locations:
- **Option 1**: Juxtaglomerular cells of the afferent arteriole and macula densa cells of the proximal convoluted tubule.
- **Option 2**: Juxtaglomerular cells of the efferent arteriole and macula densa cells of the proximal convoluted tubule.
- **Option 3**: Juxtaglomerular cells of the afferent arteriole and macula densa cells of the distal convoluted tubule.
- **Option 4**: Juxtaglomerular cells of the vasa recta and macula densa cells of the distal convoluted tubule.

4. **Selecting the Correct Answer**:
- The correct combination is:
- Juxtaglomerular cells are found in the **afferent arteriole**.
- Macula densa cells are found in the **distal convoluted tubule**.
- Therefore, the correct answer is **Option 3**: "the juxtaglomerular cells of the afferent arteriole and the macula densa cells of the distal convoluted tubule form the juxtaglomerular apparatus."

### Final Answer:
The juxtaglomerular cells of the **afferent arteriole** and the macula densa cells of the **distal convoluted tubule** form the juxtaglomerular apparatus.

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