The 4 types of phagocytosis are recognition of the target particle, signaling to activate the internalization machinery, phagosome formation, and phagolysosome maturation.
Phagocytosis is a cellular process for ingesting and eliminating particles larger than 0.5 μm in diameter, including microorganisms, foreign substances, and apoptotic cells.
Phagocytosis is found in many types of cells and it is, in consequence an essential process for tissue homeostasis.
Phagocytosis consists in recognition and ingestion of particles larger than 0.5 μm into a plasma membrane derived vesicle, known as phagosome.
Phagocytes can ingest microbial pathogens, but importantly also apoptotic cells.
An example of phagocytosis occurs when an amoeba encounters food such as paramecium.
It will release pseudopods that surround its prey. Once enclosed, a phagosome is created.
Digestive enzymes are later released into the vesicle, and the food is digested.
In phagocytosis, or "cell eating," the cell engulfs debris, bacteria, or other sizable objects.
Phagocytosis occurs in specialized cells called phagocytes, which include macrophages, neutrophils, and other white blood cells.
Phagocytosis of bacteria by human neutrophils takes on average nine minutes.
Once inside this phagocyte, the bacterium is trapped in a compartment called a phagosome.
Within one minute the phagosome merges with either a lysosome or a granule to form a phagolysosome.
Pinocytosis primarily refers to the uptake of extracellular fluids and small molecules by a cell, whereas phagocytosis is a process by which the cell membrane invaginates around large macromolecular structures (e.g., proteins and viruses) that are otherwise unable to diffuse into the cell.
Some bacteria resist phagocytic destruction by preventing fusion of the lysosome with the phagosome.
Some bacteria resist phagocytic destruction by escaping from the phagosome before the lysosome fuses.
Some bacteria resist phagocytic destruction by preventing acidification of the phagosome.