NURSING 3PA2 Study Guide - Final Guide: Systemic Lupus Erythematosus, Cytotoxic T Cell, Adaptive Immune System
4 Dec 2016
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Document Summary
First line of defence is provided by intrinsic barriers of the skin and mucus membranes which may be mechanical, chemical, or microbiological in nature. Mechanical: expulsive forces (coughing, defecation) help to rid the body of pathogens before they can attach to and break mucus membranes. Ciliary beating helps to sweep pathogens from upper and lower airways. Tight junctions in epithelium prevent pathogens from slipping between cells to enter underlying host tissue. Chemical: low ph barriers (stomach, vaginal fluids) prevent pathogenic bacterial colonization. Proteolytic enzymes (lysozymes, pepsin in gut) breakdown pathogenic components. Microbiological: commensal flora compete with pathogens for resources (space and nutrients). The second line of defence the innate immune system infers protection against a broad spectrum of pathogens through use of surface receptors on phagocytic cells that recognize evolutionary conserved patterns unique to pathogens. The innate immune system consists of many components including the following: Phagocytes: consist of tissue resident and macrophages.
