Phagocytosis is a process used by certain cells, known as phagocytes, to engulf and digest harmful particles, bacteria, or dead cells. During this process, the phagocyte surrounds the target with its cell membrane, forming a pocket that eventually pinches off to create a small vesicle called a phagosome. This vesicle then fuses with a lysosome, which contains enzymes that break down the engulfed material. Phagocytosis is an essential part of the immune system, helping to protect the body from infections and maintain tissue health. It plays a crucial role in the body's defense mechanisms, allowing white blood cells to eliminate pathogens and debris effectively.