Juxta glomerular apparatus (JGA) comprises of all of the following except:

Options

A. Macola densa cells
B. Juxta glomerular cells
C. Lacis cells
D. Principal cells

Answer

To answer the question regarding the components of the juxtaglomerular apparatus (JGA), we need to identify which of the listed options is not part of the JGA.

### Step-by-Step Solution:

1. **Understanding the Juxtaglomerular Apparatus (JGA)**:
- The JGA is a specialized structure in the kidney that plays a crucial role in regulating blood pressure and the filtration rate of the glomerulus. It is located near the glomerulus, which is part of the nephron, the functional unit of the kidney.

2. **Identify the Components of JGA**:
- The JGA is made up of three main types of cells:
- **Macula Densa Cells**: These cells are located in the distal convoluted tubule and are sensitive to sodium chloride concentration. They help regulate blood pressure and the glomerular filtration rate.
- **Juxtaglomerular Cells**: Also known as granular cells, these are located in the walls of the afferent arterioles and secrete the enzyme renin, which is important in the regulation of blood pressure.
- **Extraglomerular Mesangial Cells**: These cells are located between the glomerular capillaries and play a role in supporting the glomerulus and regulating blood flow.

3. **Analyzing the Options**:
- The options given are:
- Macula Densa Cells (Present in JGA)
- Juxtaglomerular Cells (Present in JGA)
- Basal Cells (Not part of JGA)
- Principal Cells (Not part of JGA)
- From the above analysis, we can conclude that both "Basal Cells" and "Principal Cells" are not components of the JGA. However, the principal cells are specifically associated with the collecting ducts and are not involved in the JGA.

4. **Conclusion**:
- Therefore, the correct answer to the question "Juxta glomerular apparatus (JGA) comprises of all of the following except:" is **Principal Cells**.

### Final Answer:
**Principal Cells** are not part of the Juxtaglomerular Apparatus (JGA).

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