Question

Which one of the following cell types is the most abundant in healthy adult human blood?

• A. Erythrocytes
• B. Lymphocytes
• C. Basophils
• D. Neutrophils

Hint:

Compare typical cell counts per microliter of blood for each cell type listed.

Answer 1

The Correct Option is A

This question tests basic knowledge of the cellular composition of human blood. Blood contains several types of formed elements: red blood cells (erythrocytes), white blood cells (leukocytes, including lymphocytes, basophils, and neutrophils), and platelets. Let's look at each option and compare typical counts in a healthy adult.

1. Erythrocytes: Red blood cells number about 4.5 to 5.5 million cells per microliter of blood in a healthy adult. They are by far the most numerous cell type in blood, since carrying oxygen with hemoglobin needs a very high cell density throughout the body.
2. Lymphocytes: These are a type of white blood cell involved in immunity. Their count is only about 1000 to 4000 cells per microliter, several thousand times fewer than erythrocytes.
3. Basophils: These are the rarest type of white blood cell, present at less than 100 cells per microliter in most healthy adults. They play a role in allergic and inflammatory responses.
4. Neutrophils: These are the most abundant type of white blood cell, typically 2500 to 7000 cells per microliter, but even this count is far smaller than the erythrocyte count.

Comparing all four counts, erythrocytes outnumber every white blood cell type by several orders of magnitude. So erythrocytes are the most abundant cell type in healthy adult human blood, matching option (A).

Let's summarize:

• Erythrocytes (red blood cells) vastly outnumber all classes of white blood cells in normal blood.
• Among white blood cells, neutrophils are the most common, but this is still a small fraction of the erythrocyte count.

The most abundant cell type in healthy adult human blood is erythrocytes.