Question

Macrophages phagocytose bacteria, cellular debris, and RBCs. What is the main function of macrophages?

1) To produce antibodies
2) To transport oxygen
3) To remove foreign substances
4) To regulate body temperature

Answer 1

3) Macrophages are a key part of the immune system, primarily functioning to remove foreign substances through phagocytosis and signal other immune cells via cytokines.

Step-by-step explanation:

The main function of macrophages is to remove foreign substances from the body. These large, versatile phagocytes originate from monocytes and serve as a first line of defense in the immune system. When macrophages encounter pathogens or cellular debris, they engulf and digest these invaders through a process called phagocytosis.

Additionally, macrophages release cytokines, which are signaling molecules that help to recruit and activate other immune cells. Fixed macrophages reside permanently in tissues, while roaming macrophages move around to clear debris and pathogens.

The interaction between macrophages and T-cells is crucial for the adaptive immune response, and this often occurs within lymphoid tissues such as lymph nodes. The presence of macrophages is also crucial in facilitating inflammation, which is the body's response to infection or injury.