Blood colloidal osmotic pressure mainly maintained by which plasma protein

Options

A. (a) Albumin
B. (b) Globulin
C. (c) Fibrinogen
D. (d) Thrombin

Answer

**Step-by-Step Solution:**

1. **Understand the Question**: The question asks which plasma protein is primarily responsible for maintaining blood colloidal osmotic pressure.

2. **Identify Plasma Proteins**: Plasma contains several proteins, including albumin, globulins, and fibrinogen. Each of these proteins has different functions.

3. **Focus on Albumin**: Among these proteins, albumin is the most abundant, constituting about 55% of the total protein in the blood.

4. **Function of Albumin**: The primary role of albumin is to maintain osmotic pressure in the blood. It does this by retaining water in the plasma, which helps to regulate blood volume and blood pressure.

5. **Quantify Osmotic Pressure**: Albumin maintains the colloidal osmotic pressure at approximately 25 mm Hg, which is crucial for keeping the fluid balance within the blood vessels.

6. **Consider Other Plasma Proteins**: While other plasma proteins like globulins and fibrinogen play roles in immune response and blood clotting, they do not significantly contribute to maintaining osmotic pressure.

7. **Conclusion**: Based on the information, the plasma protein that mainly maintains blood colloidal osmotic pressure is albumin.

8. **Final Answer**: The correct answer is **A) Albumin**.

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