Microbiology Practice Exam

Which white blood cell (WBC) is the most abundant type in the human body?

1. Lymphocyte

2. Monocyte

3. Neutrophil

4. Basophil

The correct answer is: Neutrophil

Neutrophils are indeed the most abundant type of white blood cells in the human body, making up about 55-70% of the total white blood cell population. They play a crucial role in the immune response, particularly in combating bacterial infections. Neutrophils are considered the first line of defense and are primarily responsible for phagocytosing (engulfing) and destroying pathogens. Their abundance is significant because during an infection or inflammation, the body can rapidly mobilize neutrophils to the site of infection, facilitating a swift immune response. Lymphocytes, while important for adaptive immunity, do not account for the largest percentage of white blood cells. Monocytes and basophils comprise even smaller proportions of the total white blood cell count, with monocytes playing roles in phagocytosis and tissue repair and basophils participating in inflammatory reactions by releasing histamine. Thus, neutrophils' high abundance aligns with their critical function in immediate defense mechanisms against pathogens.