10 phagocytosis

what happens if pathogens get past the chemical and physical barriers (such as skin and stomach acid) and enter the blood?

the white blood cells are the second line of defence

what types of responses do white blood cells have?

specific and non specific:

• phagocytes (non specific)

• lymphocytes (specific)

what’s a phagocyte?

a type of white blood cell (a macrophage) that carries out phagocytosis. they’re found in the blood and tissues

what’s phagocytosis?

a non specific response. any non self cell that is detected will trigger the same respond to destroy it

how is phagocytosis carried out?

• any chemicals/debris released by a foreign antigen will attract the phagocytes

• phagocytes have many receptor binding points on their surface and will attach to the antigen on the pathogen with the receptor

• the phagocyte changes shape to engulf the pathogen

• once engulfed, the pathogen is contained with a phagosome vesticle

• a lysosome within the phagocyte will fuse with the phagosome and release its contents

• the lysozyme enzyme is released into the phagosome, this is a lyric enzyme which hydrolyses the pathogen

• this destroys the pathogen and the soluble products are absorbed and used by the phagocyte