bacteriology ch 31

bacteriology ch 31 - 1 Chapter 31 Immune system composed of...

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Chapter 31 Immune system - composed of widely distributed cells, tissues, and organs; recognizes foreign substances or microbes and acts to neutralize or destroy them Immunity - ability of host to resist a particular disease or infection Immunology - science concerned with immune responses Nonspecific immune response - also called nonspecific resistance, innate immunity, and natural immunity; acts as a first line of defense; offers resistance to any microbe or foreign material; lacks immunological memory Specific immune response - also called acquired immunity, adaptive immunity and specific immunity; resistance to a particular foreign agent; has “memory”; effectiveness increases on repeated exposure to agent Antigens - recognized as foreign; invoke immune responses; presence of antigen in body ultimately results in B cell activation production of antibodies; antibodies bind to specific antigens, inactivating or eliminating them; other immune cells also become activated Hematopoesis -development of white blood cells in bone marrow of mammals; WBCs that mature prior to leaving bone marrow, e.g. macrophages and dendritic cells, become part of innate immune system and will respond to all antigens; WBCs that are not fully functional after leaving bone marrow become part of the adaptive immune response, e.g. B and T cells and could differentiate in response to specific antigens Leukocytes - white blood cells; involved in both specific and nonspecific immunity; all arise from pluripotent stem cells Monocytes - are mononuclear phagocytic leukocytes; after circulating for ~8 hours, mature into macrophages Macrophages - reside in specific tissues; have a variety of surface receptors; named according to tissue in which they reside; after digesting microbial fragments pass fragments from phagolysosome to endoplasmic reticulum; peptide components of fragments combine with glycoproteins which ultimately become part of cell membrane Antigen presentation - peptides bound so they are ultimately presented outward from the cell; allows wandering lymphocytes to become activated; links nonspecific and specific immune responses Basophils - stain bluish-black with basic dyes; nonphagocytic; release histamine, prostaglandins, serotonin, and leukotrienes from granules; play important role in development of allergies and hypersensitivities Eosinophils - stain red with acidic dyes; defend against protozoan and helminth parasites; release cationic proteins and reactive oxygen metabolites; may play a role in allergic reactions Neutrophils - stain at neutral pH; highly phagocytic; circulate in blood then migrate to sites of tissue damage; kill ingested microbes with lytic enzymes and reactive oxygen metabolites contained in primary and secondary granules Mast Cells - bone marrow-derived cells; differentiate in blood and connective tissue; contain granules containing histamine and other pharmacologically active chemicals; play important role in development of allergies and hypersensitivities
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This note was uploaded on 04/20/2008 for the course BIO 301 taught by Professor Tryzna during the Spring '08 term at Marshall.

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bacteriology ch 31 - 1 Chapter 31 Immune system composed of...

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