White Blood Cell (Leukocyte)

The **leukocyte**, or **white blood cell** (WBC), is a major component of the body's defense against disease. Leukocytes protect the body by targeting invading microorganisms, attacking cells with mutated DNA, and clearing away cellular debris. Platelets are essential for the repair of blood vessels they are damaged and release growth factors that support healing and tissue repair. Leukocytes are far less numerous than erythrocytes (red blood cells). Although only one type of erythrocyte exists, there are several types of leukocytes, most of which have much shorter lifespans, some lasting only a few hours or even minutes in cases of acute infection. One of the most distinctive characteristics of leukocytes is their ability to move out of the bloodstream. Unlike erythrocytes, leukocytes routinely exit the vascular network to perform defensive functions within body tissues, using blood vessels simply as pathways to reach their target areas. *LICENSES AND ATTRIBUTIONS CC licensed content, Shared previously, 18.4 Leukocytes and Platelets, Authored by: OpenStax College. License: CC BY: Attribution. License Terms: Download for free at: https://cnx.org/contents/FPtK1zmh@6.17:3xCcgfIV@5/Leukocytes-and-Platelets*