What is the primary function of white blood cells in the body?

White blood cells, also known as leukocytes, play a crucial role in the body’s immune system, primarily by fighting infections. They are responsible for identifying, attacking, and destroying microorganisms such as bacteria, viruses, fungi, and parasites that can cause disease. When pathogens invade the body, certain types of white blood cells, like neutrophils and lymphocytes, are activated to respond.

Their function involves several mechanisms, including producing antibodies that bind to pathogens, phagocytosis which involves engulfing and digesting these invaders, and releasing substances that can kill pathogens or recruit other immune cells to the site of infection. This protective response is vital for maintaining health and preventing illness, making the role of white blood cells essential in the body's defense mechanisms.