Effective net filtration pressure in the glomerulus in kidney of man is about

Options

A. `+75 m Hg`
B. `+80 mm Hg`
C. `+20 " to " 25 mm Hg`
D. `+50 mm Hg`

Answer

To determine the effective net filtration pressure in the glomerulus of the kidney in humans, follow these steps:

### Step-by-Step Solution:

1. **Understand the Concept of Filtration in the Kidney**:
- The first step in urine formation occurs in the glomerulus, where blood is filtered. This process is known as glomerular filtration.

2. **Define Glomerular Filtration Rate (GFR)**:
- The amount of filtrate produced per minute by the glomerulus is referred to as the Glomerular Filtration Rate (GFR).

3. **Identify Net Filtration Pressure (NFP)**:
- The net filtration pressure is calculated by subtracting the inward pressures from the outward pressure. The formula is:
\[ \text{Net Filtration Pressure (NFP)} = \text{Outward Pressure} - \text{Inward Pressure} \]

4. **Determine the Components of the Equation**:
- Outward pressure is primarily the glomerular hydrostatic pressure.
- Inward pressures include the glomerular osmotic pressure and the capsular hydrostatic pressure.

5. **Insert Values into the Equation**:
- The values typically used are:
- Glomerular Hydrostatic Pressure (GHP): 70 mmHg
- Glomerular Osmotic Pressure (GOP): 28 mmHg
- Capsular Hydrostatic Pressure (CHP): 20 mmHg
- Plugging these values into the equation gives:
\[ \text{NFP} = 70 \text{ mmHg} - (28 \text{ mmHg} + 20 \text{ mmHg}) \]

6. **Calculate the Net Filtration Pressure**:
- Simplifying the equation:
\[ \text{NFP} = 70 \text{ mmHg} - 48 \text{ mmHg} = 22 \text{ mmHg} \]

7. **Conclusion**:
- The effective net filtration pressure in the glomerulus of the kidney in humans is approximately **22 mmHg**.