The net pressure gradient that causes the fluid to filter out of the glomeruli into the capsule is

Options

A. 50 mm Hg
B. 75 mm Hg
C. 20mm Hg
D. 30 mm Hg.

Explanation

To solve the question regarding the net pressure gradient that causes fluid to filter out of the glomeruli into the capsule, we can follow these steps:

### Step-by-Step Solution:

1. **Understand the Concept of Filtration in the Kidney**:
- The kidneys filter blood to form urine, and this process begins in the glomeruli, where blood is filtered into the Bowman's capsule.

2. **Identify the Key Parameters**:
- The filtration process is influenced by several pressures:
- Glomerular hydrostatic pressure (GHP)
- Capsular hydrostatic pressure (CHP)
- Blood colloid osmotic pressure (BCOP)

3. **Calculate the Net Filtration Pressure (NFP)**:
- The net filtration pressure can be calculated using the formula:
\[ \text{NFP} = \text{GHP} - (\text{CHP} + \text{BCOP}) \]
- In this context, we need to determine the value of NFP that causes fluid to filter out of the glomeruli.

4. **Evaluate the Given Options**:
- The options provided are 50 mm Hg, 75 mm Hg, 20 mm Hg, and 30 mm Hg.
- Based on physiological norms, a typical net filtration pressure that allows for effective filtration is around 10 to 20 mm Hg.

5. **Select the Correct Answer**:
- Among the given options, 20 mm Hg is the most reasonable value for the net pressure gradient that facilitates the filtration of fluid from the glomeruli into the Bowman's capsule.
- Therefore, the correct answer is **20 mm Hg**.

### Final Answer:
The net pressure gradient that causes fluid to filter out of the glomeruli into the capsule is **20 mm Hg** (Option C).