phagocytosis

 Phagocytosis

Phagocytosis is a cellular process by which foreign particle or infectious agents are ingested and digested by phagocytic cells.

The major lysoenzymes through which phagocytic cell kill microorganism include;

Lysoenzymes are; Lysozyme, Hyaluronidase, Collagenases, Lipases, Ribonuclease, Elastases

Process of Phagocytosis

The process of phagocytosis requires a preliminary attach of the microbes to the phagocytic cell surface.

The process of phagocytosis consist 4 stages;

Stages are;

1. Chemotaxis

Phagocytes reach site of infection, bring attracted by chemotactic substances produced at the site of infection.

2. Attachment

Infective agent gets attached or adhered to membrane of phagocyte.

3. Ingestion

Phagocytes engulf the infective agent/ material into a vacoule (phagosome), the membrane of which fuses with a lysosome in cytoplasm forming phagolysosome.

Lysosome contains hydrolytic enzymes and other bactericidal substance.

4. Intracellular Digestion 

Intracellular digestion of engulfed microbes takes place few minutes of phagocytosis by action of hydrolytic enzyme. 

The bacterial component are degarded in several hours.

Phagocytic Cell

1. Microphages 

Polymorphonuclear leucocytes called polymorphs (neutrophils) contains numerous enzyme and antibacterial substance for killing and degradation of bacteria.

2. Macrophages

These are mononuclear phagocytic cells include; Monocytes.

Present in kuffer cells (in liver), spleen, lymph nodes, thymus.

When macrophages ingest a microorganisms, the phagocytic cell increases it oxygen consumption term as "respirator brust".