PHS 3342 Lecture Notes - Lecture 2: White Blood Cell, Mhc Class Ii, C3B

• School: University of Ottawa
• Department: Physiology
• Course: PHS 3342
• Professor: Jacqueline Carnegie

Document Summary

Innate defenses: protect against foreign substances/abnormal cells without having to specifically identify them (generalized carbohydrate/lipid cell surface markers bind to toll-like receptors (tlrs) on phagocytic cells) Innate defenses include: inflammation, interferon, natural killer cells, the complement system. Adaptive defenses: (= acquired immunity) subpopulations of lymphocytes recognize and attack the specific target. Innate defenses (nonspecific: external defenses: skin & mucous membranes. Effective, but can be breached: physical barrier of skin & mucosal membranes. Salt = skin-associated lymphoid tissue: skin acidity, flow of urine, vaginal secretions; sebum contains bactericidal chemicals, gastric hcl; saliva and lacrimal fluid contain lysozyme (destroys bacterial cell walls, mucus in respiratory (mucus elevator) & digestive passageways. In many instances, the skin modifies compounds that come into contact with it. For example, epidermal enzymes can convert many potential carcinogens into harmless compounds. Some materials, however, especially lipid-soluble substances, can penetrate intact skin through the lipid bilayers of the plasma membranes of the epidermal cells.