Ónæmisfrumur

Ónæmisfrumur, also known as immune cells, are the fundamental components of the immune system in all multicellular organisms. Their primary function is to protect the body from disease by identifying and killing pathogens, such as bacteria, viruses, and parasites, as well as abnormal cells like cancer cells. These cells are generated in the bone marrow and can be found throughout the body, circulating in the blood and lymph fluid, or residing in tissues.

There are various types of specialized immune cells, each with distinct roles. White blood cells, or leukocytes, are the main category. Lymphocytes, including B cells and T cells, are crucial for adaptive immunity, which involves recognizing specific pathogens and developing immunological memory. B cells produce antibodies that neutralize threats, while T cells can directly kill infected cells or regulate the immune response.

Phagocytes, such as macrophages and neutrophils, are responsible for engulfing and digesting pathogens and cellular debris. Natural killer cells (NK cells) are another type of lymphocyte that can kill infected or cancerous cells without prior sensitization. Other immune cells include dendritic cells, which present antigens to T cells, and mast cells, involved in allergic responses. The coordinated action of these diverse immune cells is essential for maintaining health and preventing illness.