Which term describes the process of white blood cells moving through blood vessel walls?

The process of white blood cells moving through blood vessel walls is known as diapedesis. This term specifically refers to the ability of white blood cells to squeeze through the endothelial cells of blood vessels to reach sites of infection or inflammation. During inflammatory responses, white blood cells adhere to the blood vessel walls, then alter their shape and pass through the junctions between endothelial cells. This movement is crucial for the immune response, allowing white blood cells to reach tissues where they can perform their defensive functions more effectively.

Phagocytosis involves the engulfing of pathogens or debris by white blood cells, which is related but distinct from the movement through blood vessel walls. Margination refers to the process where white blood cells line up along the endothelium of blood vessels, preparing to exit into the tissues but does not itself denote the act of passing through the vessel walls. Exocytosis is a cellular process to expel materials from the cell, which does not specifically relate to the movement of white blood cells through vessel walls. Therefore, diapedesis is the most accurate term to describe this critical function of white blood cells.