Final answer:
Phagocytosis is the biological process where cells, like neutrophils, engulf and digest large particles, such as microorganisms, through a series of steps involving pseudopodia extension, phagosome formation, and lysosomal digestion. It is a form of endocytosis, distinct from pinocytosis, which involves the uptake of fluids and dissolved substances.
Step-by-step explanation:
Phagocytosis, often referred to as cell eating, is a critical biological process by which cells engulf and ingest large particles. This process is vital for the immune response, allowing cells such as neutrophils to eliminate invading microorganisms. The stages of phagocytosis include the extension of pseudopodia to envelop the target particle, the formation of a phagosome, the fusion of a lysosome with the phagosome, and the subsequent breakdown of the particle with hydrolytic enzymes.
Neutrophils play a pivotal role in the body's defenses, patrolling tissues for pathogens or debris. Upon finding an invader, the neutrophil's membrane extends outwards to surround the microorganism, pulling it into the cell to form an internal vesicle known as a phagosome. Lysosomes then fuse with these phagosomes and release enzymes to digest the engulfed particles, creating a process essential for protecting the organism from infection.
Contrasting with phagocytosis is pinocytosis, or cell drinking, which involves the ingestion of dissolved substances and fluids into a cell. Both of these processes are forms of endocytosis, a general term for the uptake of material by a cell.