Phagocytosis

Neutrophils

Early responder to inflammation.

Macrophages

Monocytes transformed. scavengers. either histiocytes = reside in one location OR Drift throughout RES. under go phagocytosis. interact with B and T cells.

Phagocytic cells

Neutrophils. Eosinophils. Macrophages.

4 steps to phagocytosis

Recognition. Engulfment. Digestion. Expulsion.

Recognition

Step 1: Phagocytes have proteins called cell surface receptors. these bind to the antigenic determinants of pathogens. Recognizes cells different from self. LPS of gram negatives. Peptidoglycan.

Engulfment

Step 2. Once attached, the macrophage extends pseudopods around the pathogen and engulfs it, producing a phagosome.

Digestion

Step 3. Phagosome merges with a lysosome forming a phagolycosome, and the chemicals within it diges the pathogen. 30 min or less!

Expulsion

Step 4. after digestion the phagolysosome fuses with the cell membrane and expels undigested materials.

Neutrophils

primary components of pus

Phagocytosis

the ingestion of bacteria or other material by phagocytes and amoeboid protozoans

Destructon

within the phagolysosome: Oxygen=dependent system, oxidazing burst. Enzymes. Nitric oxide. undigested debris are release.