Phagocytosis - The Ingestion Of A Particulate Matter Involving The

Phagocytosis - the ingestion of a particulate matter involving the use of pseudopodia to surround the particle. Phagosome – a membrane-bound vesicle containing an ingested particle such as bacterial cell. Phagolysosome – a membrane-bound vesicle formed by the fusion of a phagosome and a lysosome. MECHANISMS OF PHAGOCYTOSIS 4 phases

 





Chemotaxis - the movement of cells in the response to a chemical - the chemical attraction of a phagocyte to a microorganism. Adherence - the attachment of the phagocyte’s plasma membrane to the surface of the microorganism. - in some instances the adherence occur easily and the microorganism is readily phagocytized. However, adherence can be hampered by the presence of large capsules. Heavily encapsulated microorganisms can be phagocytized only if the microorganism against a rough surface, such as blood vessel, blood clot, or connective tissue from which the microorganism cannot slide away. Ingestion - the plasma membrane of the phagocyte extends pseudopods that engulf the microorganism. - once the pseudopods meet and fuse, surrounding the microorganism with a sac called phagosome or phagocytic vacuole. Digestion – the phagosome enters the cytoplasm and it contacts lysosome which contains digestive enzymes and bactericidal properties. - once enzymes have digested the contents of the phagolysosomes brought into the cell by ingestion, the phagolysosomes moves towards the cell boundary and discharges wastes. PHAGOCYTOSIS 1. A phagocyte has attached to a bacterial cell wall 2. Pseudopodia extend around the bacterial cell 3. The pseudopodia meet s and fuse together, 4. The bacterial cell surrounded by a membrane is now inside the phagocyte 5. A lysosome, containing digestive enzyme, approaches a phagosome 6. A lysosome and phagosome become a single membrane-bound vesicle known as phagolysosome which contains the ingested bacterial cells and digestive enzymes. 7. The bacterial cell is digested with in the phagolysosome.