The protein primarily involved in the maintenance of circulatory blood is

Options

A. Fibrogen
B. Prothombin
C. Albumin
D. Fibrin

Answer

To solve the question regarding the protein primarily involved in the maintenance of circulatory blood, we will analyze the options and their functions step by step.

### Step 1: Identify the Proteins Involved in Blood Circulation
We need to consider the proteins that play a significant role in the circulatory system. The options mentioned include Fibrinogen, Prothamine, and Albumin.

### Step 2: Analyze Fibrinogen
Fibrinogen is a protein that acts as a clotting factor. It is crucial in the blood coagulation process. When there is an injury, fibrinogen is converted into fibrin, which helps in forming a blood clot. However, while it is important for clotting, it does not primarily maintain the circulatory blood.

**Hint:** Fibrinogen is essential for clotting but not for maintaining blood circulation.

### Step 3: Analyze Prothamine
Prothamine is also involved in the clotting process. It works alongside fibrinogen to help form a clot when bleeding occurs. Similar to fibrinogen, while it is important for stopping bleeding, it does not play a primary role in maintaining the overall circulation of blood.

**Hint:** Prothamine is another clotting factor, but like fibrinogen, it does not maintain blood circulation.

### Step 4: Analyze Albumin
Albumin is a protein found in blood plasma and constitutes about 50% of the proteins in plasma. Its primary functions include maintaining oncotic pressure, which prevents the leakage of fluids from blood vessels, and facilitating the transport of hormones, fatty acids, and other substances. This makes albumin crucial for maintaining the volume and pressure of blood, thus playing a significant role in the circulatory system.

**Hint:** Albumin helps maintain blood volume and pressure, which is essential for circulation.

### Step 5: Conclusion
Based on the analysis, the protein primarily involved in the maintenance of circulatory blood is **Albumin**. It is responsible for keeping the blood from leaking out of the vessels and ensuring proper circulation.

**Final Answer:** Albumin