Non Specific Immunity

A pathogen is a bacterium, virus or other organism that can cause disease

Epithelial cells form a physical barrier Closely packed epithelial cells are found in the skin and inner linings of the digestive and respiratory systems

Chemical secretions including tears, saliva, mucus and stomach acid are produced against invading pathogens

During the inflammatory response, histamine is released by mast cells causing vasodilation and increased capillary permeability The increased blood flow leads to an accumulation of phagocytes and clotting elements at the site of infection

Phagocytes are white blood cells that recognise pathogens and destroy them by phagocytosis

Phagocytosis involves the engulfing of pathogens and their destruction by digestive enzymes contained in lysosomes Phagocytes release cytokines which attract more phagocytes to the site of infection Cytokines are protein molecules that act as a signal to specific white blood cells causing them to accumulate at the site of infection