Anatomy and Physiology II Practice Test

What is the primary function of albumin in the blood?

1. Transport hormones

2. Maintain osmotic pressure

3. Clot blood

4. Fight infections

The correct answer is: Maintain osmotic pressure

Albumin is a protein synthesized by the liver and is the most abundant protein in human plasma. Its primary function is to maintain osmotic pressure within the blood, which helps to regulate the distribution of fluids between blood vessels and bodily tissues. By doing this, albumin plays a crucial role in ensuring that the proper balance of fluids is maintained, preventing excessive fluid accumulation in tissues (edema) and helping to stabilize blood volume and pressure. While albumin does have roles in transporting certain substances, such as hormones and fatty acids, its most critical and well-studied function is its contribution to oncotic pressure. This function is vital for homeostasis and overall fluid balance in the body. Other proteins may be more directly involved in processes such as blood clotting or fighting infections, but albumin's significance lies primarily in its role in maintaining osmotic pressure.