Question

Which of the following is the most abundant WBCs?
A. Neutrophils
B. Eosinophils
C. Basophils
D. Monocyte

Answer 1

Hint: White blood cells are also called leukocytes. Granular leukocytes involved in the non-specific immune responses make up most of the WBCs of the blood. These WBCs squeeze through the walls of the blood vessels to arrive at the site of injury or infection and are involved in the inflammatory response.

Complete answer:
Blood is connective tissue and is composed of liquid plasma and the suspended formed elements. Red blood cells (RBCs), white blood cells (WBCs), and platelets are the formed elements or cells of the blood.
Blood plasma constitutes 55% of the whole blood while the formed elements contribute its 45%. Red blood cells are the most abundant formed elements of the blood while white blood cells are the least abundant.
White blood cells include neutrophils, lymphocytes, monocytes, eosinophils, and basophils. Among these different types of WBCs, neutrophils are the most abundant and make 60-70% of the total WBCs present in the blood. Basophils are the least abundant WBCs and make only 0.5-1.0% of it. Eosinophils and monocytes make 2-4% and 3-8% of the total WBCs respectively.
Neutrophils are the granular white blood cells that are involved in phagocytosis of pathogens, specifically bacteria. They are large cells with multilobed nuclei and granules present in their cytoplasm.

So, the correct answer is option A. Neutrophils.

Note: White blood cells or leukocytes are of two types: granular and agranular. The neutrophils, eosinophils, and basophils are the granular leukocytes while lymphocytes and monocytes are the agranular leukocytes. Neutrophils are the first type of WBCs that respond to the presence of pathogens or antigens in the body.