BIO 126 Lecture Notes - Lecture 7: Neutrophil, Apoptosis, Macrophage
19 Apr 2016
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Document Summary
Immune system- enables an animal to avoid or limit infections. Adaptive immunity- specific immunity found only in vertebrates. Recognizes traits shared by a broad range of pathogens. Consists of internal & external barriers & chemical defenses. Develops after exposure to microbes, toxins, or foreign substances. In digestive system, enzyme lysozyme breaks down bacterial cell walls. Leukocytes (white blood cells)- carry out phagocytosis- engulfing cells to breakdown foreign substances. Skin & mucous membranes of respiratory, urinary, & reproductive tracks. Reinforced w/ chemical weapons ph of 3-5 given by oil and sweat glands. Contains normal flora- nonpathogenic microorganisms that out compete pathogenic organisms. Saliva, mucous, & tears are all hostile to microbes. Low ph of skin & digestive system prevents bacterial growth. Phagocytic cells recognize groups of pathogens by toll-like receptors (tlrs) Mammalian tlrs bind to fragments of molecules characteristic to a set of pathogens. Releases granzymes to trick cell to kill itself.
