Innate immune system defenses include __.
options: A) T cells B) plasma cells C) phagocytosis D) B cells
The correct answer and explanation is:
The correct answer is C) phagocytosis.
The innate immune system is the body’s first line of defense against pathogens. It provides a rapid, non-specific response to a wide range of infectious agents. One of the main mechanisms involved in innate immunity is phagocytosis. Phagocytosis is the process by which certain immune cells, such as macrophages and neutrophils, engulf and digest foreign particles, bacteria, and dead or dying cells. These phagocytic cells patrol the body, recognizing common features of pathogens through pattern recognition receptors. Once a pathogen is engulfed, it is enclosed in a vesicle called a phagosome, which then fuses with a lysosome containing enzymes that destroy the pathogen.
T cells and B cells, mentioned in options A and D, are part of the adaptive immune system, not the innate immune system. The adaptive immune system responds more slowly and specifically to pathogens, and it involves the production of antibodies and the activation of specialized cells to target specific antigens. Plasma cells, option B, are differentiated B cells that produce antibodies, and they also belong to the adaptive immune response.
The innate immune system includes physical barriers like the skin and mucous membranes, chemical barriers like stomach acid, and cellular defenses like phagocytosis. In addition to phagocytosis, other components of the innate immune system include natural killer cells, the complement system, and inflammatory responses.
Phagocytosis is essential because it not only helps remove pathogens but also activates other parts of the immune system by presenting pieces of the pathogens to adaptive immune cells. This creates a bridge between innate and adaptive immunity, ensuring a coordinated defense against infection.