(also spelled leukocytes), commonly known as white blood cells (WBCs) , are the mobile units of the body's defensive system. They are produced in the bone marrow and lymph tissue and are distributed throughout the blood and lymphatic systems. Unlike red blood cells, all leucocytes have nuclei, which is their primary distinguishing feature. Classification of Leucocytes
: Primarily involved in battling parasitic infections and allergic responses.
: The most numerous, acting as first responders to infection. leucocyte
: Certain leucocytes, like neutrophils and macrophages, ingest and destroy harmful germs and cellular debris.
: Large cells that migrate into tissues to become macrophages, which engulf debris and pathogens. (also spelled leukocytes), commonly known as white blood
: They move from the bloodstream into tissues via the lymphatic vasculature using chemokine-directed "amoeboid movement".
: Specific cell adhesion molecules (CAMs) allow leucocytes to stick to vascular endothelial cells, a process essential for reaching the site of an injury or infection. : Large cells that migrate into tissues to
The primary role of leucocytes is to protect the body against infectious diseases and foreign entities. They achieve this through several critical processes: