High blood pressure is maintained in glomeruli than in other capillaries because
(a) The variability of the diameters of arterioles causes higher resistance to blood flowing out of the glomeruli than that flowing out of the capillaries
(b) Glomerulus has low hydrostatic pressure than capillary
(c) Capillary has lesser diameter than glomerulus
(d) All the above

Options

A. The variability of the diameters of arterioles causes higher resistance to blood flowing out of the glomeruli than that flowing out of the capillaries
B. Glomerulus has low hydrostatic pressure than capillary
C. Capillary has lesser diameter than glomerulus
D. All the above

Answer

To solve the question regarding why high blood pressure is maintained in glomeruli compared to other capillaries, we will analyze each option step by step.

### Step 1: Understanding the Structure of the Glomerulus
The glomerulus is a network of capillaries located at the beginning of the nephron in the kidney. It consists of two types of arterioles: the afferent arteriole (which brings blood into the glomerulus) and the efferent arteriole (which carries blood away from the glomerulus).

**Hint:** Remember that the afferent arteriole has a larger diameter compared to the efferent arteriole.

### Step 2: Analyzing Option (a)
Option (a) states that the variability of the diameters of arterioles causes higher resistance to blood flowing out of the glomeruli than that flowing out of the capillaries. This is true because the efferent arteriole has a smaller diameter than the afferent arteriole, which increases resistance and helps maintain high pressure in the glomerulus.

**Hint:** Consider how the diameter of the arterioles affects blood flow and pressure.

### Step 3: Analyzing Option (b)
Option (b) claims that the glomerulus has lower hydrostatic pressure than capillaries. This is incorrect. In fact, the hydrostatic pressure in the glomerulus is higher than in other capillaries, which is essential for the process of ultrafiltration.

**Hint:** Hydrostatic pressure is crucial for filtration; think about where the pressure is highest.

### Step 4: Analyzing Option (c)
Option (c) states that capillaries have a lesser diameter than the glomerulus. This is misleading. While individual capillaries may have a smaller diameter than the entire glomerulus, the comparison should be made between the afferent and efferent arterioles. The efferent arteriole has a smaller diameter than the afferent arteriole, which contributes to the pressure difference.

**Hint:** Focus on the comparison between the arterioles rather than the glomerulus and capillaries.

### Step 5: Analyzing Option (d)
Option (d) states "All of the above." Since options (b) and (c) are incorrect, option (d) cannot be true.

**Hint:** Evaluate each option carefully to determine if they all can be true simultaneously.

### Conclusion
Based on the analysis:
- Option (a) is correct because the difference in diameters of the arterioles creates higher resistance, maintaining high blood pressure in the glomeruli.
- Options (b) and (c) are incorrect, and therefore option (d) is also incorrect.

The correct answer is **(a)**.