Summary of Innate (Nonspecific) Body Defenses Flashcards
Intact skin (epidermis) (Surface membrane barriers—first line of defense)
Forms mechanical barrier that prevents entry of pathogens and other harmful substances into body
Acid mantle (Surface membrane barriers—first line of defense)
Skin secretions make epidermal surface acidic, which inhibits bacterial growth; sebum also contains bacteria-killing chemicals
Keratin (Surface membrane barriers—first line of defense)
Provides resistance against acids, alkalis, and bacterial enzymes
Intact mucous membranes (Surface membrane barriers—first line of defense)
Form mechanical barrier that prevents entry of pathogens
Mucus (Surface membrane barriers—first line of defense)
Traps microorganisms in respiratory and digestive tracts
Nasal hairs (Surface membrane barriers—first line of defense)
Filter and trap microorganisms and other airborne particles in nasal passages
Cilia (Surface membrane barriers—first line of defense)
Propel debris-laden mucus away from lower respiratory passages
Gastric juice (Surface membrane barriers—first line of defense)
Contains concentrated hydrochloric acid and protein-digesting enzymes that destroy pathogens in stomach
Acid mantle of vagina (Surface membrane barriers—first line of defense)
Inhibits growth of bacteria and fungi in female reproductive tract
Lacrimal secretion (tears); saliva (Surface membrane barriers—first line of defense)
Continuously lubricate and cleanse eyes (tears) and oral cavity (saliva); contain lysozyme, an enzyme that destroys microorganisms
Phagocytes (Cellular and chemical defenses—second line of defense)
Engulf and destroy pathogens that breach surface membrane barriers; macrophages also contribute to immune response
Natural killer cells (Cellular and chemical defenses—second line of defense)
Promote cell lysis by direct cell attack against virus-infected or cancerous body cells; do not depend on specific antigen recognition
Inflammatory response (Cellular and chemical defenses—second line of defense)
Prevents spread of injurious agents to adjacent tissues, disposes of pathogens and dead tissue cells, and promotes tissue repair; releases chemical mediators that attract phagocytes (and immune cells) to the area
Antimicrobial chemicals- Complement (Cellular and chemical defenses—second line of defense)
Group of plasma proteins that lyses microorganisms, enhances phagocytosis by opsonization, and intensifies inflammatory response.
Antimicrobial chemicals- Interferons (Cellular and chemical defenses—second line of defense)
Proteins released by virus-infected cells that protect uninfected tissue cells from viral takeover; mobilize immune system
Antimicrobial chemicals- Fluids with acid pH (Cellular and chemical defenses—second line of defense)
Normally acid p H inhibits bacterial growth; urine cleanses the lower urinary tract as it flushes from the body
Fever (Cellular and chemical defenses—second line of defense)
Systemic response triggered by pyrogens; high body temperature inhibits multiplication of bacteria and enhances body repair processes