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Phagocytosis (from Ancient Greek φαγεῖν (phagein) 'to eat' and κύτος (kytos) 'cell') is the process by which a cell uses its plasma membrane to engulf a large particle (≥ 0.5 μm), giving rise to an internal compartment called the phagosome. It is one type of endocytosis. A cell that performs phagocytosis is called a phagocyte.
Steps of a macrophage ingesting a pathogen: a. Ingestion through phagocytosis, a phagosome is formed b. The fusion of lysosomes with the phagosome creates a phagolysosome; the pathogen is broken down by enzymes c. Waste material is expelled or assimilated (the latter not pictured) Parts: 1. Pathogens 2. Phagosome 3. Lysosomes 4. Waste material ...
Steps of a macrophage ingesting a pathogen. After recognizing an antigen, an antigen-presenting cell such as the macrophage or B lymphocyte engulfs it completely by a process called phagocytosis. The engulfed particle, along with some material surrounding it, forms the endocytic vesicle (the phagosome), which fuses with lysosomes.
C5a has the highest specific biological activity and is able to act directly on neutrophils and monocytes to speed up the phagocytosis of pathogens. C3a works with C5a to activate mast cells, recruit antibody, complement and phagocytic cells and increase fluid in the tissue, all of which contribute to the initiation of the adaptive immune response.
Unbound phagocyte surface receptors do not trigger phagocytosis. 2. Binding of receptors causes them to cluster. 3. Phagocytosis is triggered and the particle is taken up by the phagocyte. Phagocytosis is the process of taking in particles such as bacteria, invasive fungi, parasites, dead host cells, and cellular and foreign debris by a cell. [22]
Thus, phagocytosis is not a randomly occurring event. It is triggered by a ligand binding to a receptor. Some cells are specially designed to phagocytize. These cells include Natural Killer cells, macrophages, and neutrophils. All of these are involved in the immune response and serve to degrade foreign or antigenic material [4]
The cleaved products attract phagocytes to the site of infection and tags target cells for elimination by phagocytosis. In addition, the C5 convertase initiates the terminal phase of the complement system, leading to the assembly of the membrane attack complex . The membrane attack complex creates a pore on the target cell's membrane, inducing ...
For example, following phagocytosis, the ingested particle (or phagosome) fuses with a lysosome containing hydrolytic enzymes to form a phagolysosome; the pathogens or food particles within the phagosome are then digested by the lysosome's enzymes.