In a typical healthy adult, approximately what percentage of whole blood volume is composed of plasma?

• A. About 45%
• B. About 25%
• C. About 55%
• D. About 75%

Answer: (C)

Verified step by step guidance

1. Understand that whole blood is composed of two main components: plasma and formed elements (such as red blood cells, white blood cells, and platelets).
2. Recall that plasma is the liquid portion of blood, which carries nutrients, hormones, and waste products, and typically makes up the majority of blood volume.
3. Recognize that in a typical healthy adult, plasma usually accounts for a bit more than half of the total blood volume.
4. Use the general physiological knowledge that plasma volume is approximately 55% of whole blood volume, while the remaining 45% consists of formed elements, primarily red blood cells.
5. Therefore, the percentage of whole blood volume composed of plasma is about 55%, which aligns with the correct answer choice.