.Infection is frequent when this barrier is breached.
g. Wounds, Burns
Mucus membrane: A single layer of epithelium and less
protective than skin.
(peptidoglycan) of the Gram-positive bacteria. d. Normal flora: Prevents establishment of pathogenic bacteria.
Flushing of tears, urine and respiratory secretion e. Tears: Keep the eye surface sterile due to lysozyme and flushing.
f. Respiratory secretion: Traps bacteria and constantly moves them upward propelled by cilia on the cells of the epithelium.
Urine: Voiding helps to flush out bacteria that have gained entry to the bladder. pH of body tract
Low pH in stomach due to hydrochloric acid secretion kills ingested bacteria.
Low pH in vagina due to lactic acid conferred by lactobacilli spp. prevents entry of pathogenic bacteria. i. Phagocytosis: The process by which microorganisms are ingested and destrrroyed by phagocytic cells.
There are two types of phagocytic cells. 1. Neutrophil polymorphonuclear leukocytes (The polymorphs) . Produced and mature I bone marrow. . Short lived cells; circulate in the blood stream for six hours. . Act as an early defense against infection and are the “pus cells” seen in the exudate from acute infection.