Phagocytosis
โlarge particle can be engulfed by cells in the vesicles formed from the cell-surface
membrane.
โThe types of white blood cells that carry out phagocytosis are known as
phagocytes
โThey provide an important defense against the pathogens that manage to
enter the body
โSome phagocytes travel in the blood but can move out of blood vessels into
other tissues
โchemical products of pathogens or dead, damaged, and abnormal cells act as
attractants, causing phagocytes to move towards the pathogen
โPhagocytes have several receptors on their cell-surface membrane that
recognize, and attach to, chemicals on the surface of the pathogen
โThey engulf the pathogen to form a vesicle, known as a phagosome
โLysosomes move towards the vesicle and fuse with it
โEnzymes called lysozymes are present within the lysosomes. These lysozymes
destroy ingested bacteria by hydrolysis of their cell walls. The process is the
same as that for the digestion of food in the intestines, namely the hydrolysis of
larger, insoluble molecules into smaller, soluble ones
โThe soluble products from the breakdown of the pathogen are absorbed into the
cytoplasm of the phagocyte
โNeutrophil
โMacrophage do same job
โMacrophage has glycoproteins on surface
โRecognize apc-antigen presenting cells
โAny cell that presents antigens should not be there
โAttach onto antigens being presented by
โOnce attached-engulfs
โForms vesicle around thing absorbed
โPart of membrane opens up
โLysosomes will go into vesicle-phagosome
โForming a phagolysosome
โEnzymes break down biological molecules
โ
