Final answer:
Phagocytosis is the process by which phagocytes engulf and destroy pathogens. Phagocytes, such as macrophages and neutrophils, capture pathogens in a phagosome that merges with a lysosome to digest the pathogen, followed by the expulsion of debris.
Step-by-step explanation:
Pathogens are destroyed by being engulfed during a process called phagocytosis. This critical function of the immune system involves immune cells known as phagocytes, which include types such as macrophages and neutrophils. During phagocytosis, the phagocyte extends its membrane to surround and eventually engulf the pathogen, forming a vesicle known as a phagosome. This phagosome then fuses with a lysosome, creating a phagolysosome, where powerful digestive enzymes and acids work to eliminate the pathogen. The process concludes with the phagocyte expelling the residual debris through exocytosis.