immunijärjestelmän

Immunijärjestelmän, often translated as the immune system, is the complex network of cells, tissues, and organs that work together to defend the body against harmful invaders. These invaders, known as pathogens, include bacteria, viruses, fungi, and parasites. The immune system's primary function is to distinguish between the body's own cells and foreign substances, and then to neutralize or eliminate the latter.

The immune system operates through various mechanisms. One crucial component is the innate immune system, which provides a rapid, non-specific response to threats. This includes physical barriers like the skin and mucous membranes, as well as cellular defenses such as phagocytes that engulf and destroy pathogens. If the innate immune system cannot contain an infection, the adaptive immune system is activated. This system is highly specific and develops memory, meaning it can recognize and mount a stronger defense against pathogens it has encountered before. Key players in the adaptive immune system are lymphocytes, specifically B cells that produce antibodies and T cells that directly attack infected cells or regulate immune responses.

Disruptions in the immune system can lead to various health issues. An overactive immune system can result in autoimmune diseases, where the body mistakenly attacks its own healthy tissues. Conversely, a weakened immune system, known as immunodeficiency, leaves the body vulnerable to infections. Research into the immune system continues to advance our understanding of health and disease, leading to new treatments and preventative strategies.