What type of cell is a macrophage classified as in the immune system?

Macrophages are classified as phagocytic cells in the immune system because their primary function is to engulf and digest pathogens, dead cells, and cellular debris. They play a critical role in the innate immune response, serving as one of the first lines of defense against infections. Macrophages are derived from monocytes and are able to migrate to sites of infection or inflammation, where they perform phagocytosis.

Phagocytosis involves the recognition of foreign particles, followed by their ingestion and degradation within the macrophage. This process is essential for the clearance of pathogens and for the activation of other immune cells. In addition to their phagocytic abilities, macrophages also secrete various cytokines and chemokines, which help coordinate the immune response and attract other immune cells to the site of infection.

The other options provided—B lymphocytes, eosinophils, and natural killer cells—serve different functions in the immune system. B lymphocytes are primarily involved in the adaptive immune response, producing antibodies. Eosinophils are mainly involved in combating parasitic infections and have a role in allergic reactions. Natural killer cells are part of the innate immune system and are responsible for targeting and destroying virally infected cells and tumor cells