Anatomy and Physiology II Practice Test

Which white blood cells are the most numerous of the phagocytes?

1. Lymphocytes

2. Monocytes

3. Neutrophils

4. Eosinophils

The correct answer is: Neutrophils

Neutrophils are the most numerous type of white blood cells and play a vital role in the immune response, particularly in the innate immunity. They account for approximately 50-70% of all circulating white blood cells, making them the predominant phagocytes in the bloodstream. Their primary function is to engulf and digest pathogens, such as bacteria and fungi, through a process called phagocytosis. When an infection occurs, neutrophils are among the first responders, quickly migrating to the site of infection where they consume microorganisms and release enzymes that help to break them down. Their high abundance and rapid action make them essential for the immediate defense against pathogens. Other white blood cells, such as lymphocytes, monocytes, and eosinophils, play important roles in the immune system, but they are not as numerous or as quick to respond as neutrophils. Lymphocytes are more involved in the adaptive immune response, while monocytes can differentiate into macrophages to enhance phagocytosis, but they are present in smaller numbers. Eosinophils are primarily associated with combating parasitic infections and allergic reactions, making them less relevant in terms of immediate phagocytic action. Thus, neutrophils are critical players in