Immunology | Immune system| Immunity

WBC Physiology:
             Once pathogens enter the body,the general function of WBC is to fight or combat by phagocytosis or immune responses.Neutrophils and macrophages are active in phagocytosis.Several different chemicals in the inflammed tissue attract phagocytes towards the tissue,this phenomenon is called chemotaxis.Among the substances that provide stimuli for chemotaxis are toxins produced by microbes,specialised products of damaged tissues called Kinins.


             Most Leucocytes possess the ability to squiz through walls of capillaries and this movement through walls is called Diapedes.Among the WBCs neutrophils respond tissue destruction by bacteria most quickly.After engulfing a pathogen during phagocytosis neutrophils releases several destructive chemicals such as antibacterial enzyme Lysozyme and strong oxidants like  hydrogen peroxide.Neutrophils also contain Defensins specialized proteins that exhibit a broad range of antibiotic activity against bacterial,fungi and viruses.As compared to neutrophils monocytes take a little longer to reach a site of infection but once they arrive,they arrive in large number and destroy microbes.On their arrival at a site of infection monocytes enlarge and differentiate into wandering macropahges which clean up cellular debris,following the infection Eosinophils are believed to release enzymes such as histaminase that combats the effects of Histamine is allergic reactions.Eosinophils are most effective against parasitic worms a high high eosinophil count often indicates prarsitic infection.Basophils are also involved in inflammatory and allergic reactions.They develop into mast cells which liberate chemicals like Histamine,Heparin and Serotonin.These substances intensify inflammatory reactions and are involved in hypersnsitivity or allergic reactions.