Which process describes the movement of white blood cells to the site of infection?

The process that describes the movement of white blood cells to the site of infection is diapedesis. During an infection, white blood cells (leukocytes) migrate from the bloodstream to the affected tissues. This movement typically occurs in response to signaling molecules released by damaged tissues or pathogens. Diapedesis involves the leukocytes squeezing through the endothelial cells lining the blood vessels in a process that is facilitated by changes in the cell's shape and adhesion properties. This allows them to exit the circulation and reach the site of infection where they can perform their immune functions, such as engulfing pathogens or producing inflammatory mediators.

To clarify the context of the other processes: adhesion refers to the sticking of immune cells to the blood vessel walls, a preliminary step that might precede diapedesis but does not refer to their actual movement into the tissues. Phagocytosis is the process by which white blood cells ingest and digest foreign particles, while apoptosis is programmed cell death, a process that helps regulate cell populations in the body, but does not directly relate to the movement of cells toward an infection site.