Session 18 (Natural Defense against Disease)

Session 18 (Natural Defense against Disease) - MCB 181...

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MCB 181 Study Session 18 (Natural Defense Against Disease) Phagocyte Plasma Cell
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Learning Goals for Study Session 18 (Natural Defense Against Disease) Be able to briefly describe the external and internal nonspecific defenses against invading microorganisms with emphasis on the inflammatory response. Be able to list the essential characteristics of the bodies specific immune response to pathogens. Describe the role of MHC molecules in the ability of cells in the immune system to distinguish between self and non-self. Be able to distinguish between T cell receptor and antibody, and describe their roles in the clonal selection process. Distinguish between the humoral and cell mediated immune responses with emphasis on the role of helper T cells in both responses. Briefly describe why the HIV virus compromises the immune response.
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Natural Defense Against Disease Humans and other vertebrate animals have extraordinary mechanisms for defending themselves against invading pathogens. The first line of defense consists of the skin and mucous membranes that cover the external surfaces of the body and those internal surfaces that are open to the outside. These nonspecific (innate) defenses provide a physical barrier retarding access to internal organs. The second line of defense is triggered by an abrasion to the skin or mucous membrane which leads to an inflammatory response involving antimicrobial proteins and phagocytic white blood cells. The third line of defense is triggered when an organism gains access to internal organs. This specific immune response leads to selection of specialized lymphocytes and production of antibodies that label the invading organism for destruction. In this study session we consider the bodies defense mechanisms with particular emphasis on the extraordinary cells of the immune system.
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First Line of Defense--Skin and Mucous Membranes Intact skin provides a barrier to entry of bacteria and viruses. Minor abrasions compromise the barrier. Mucous membranes lining the digestive, respiratory, and genitourinary tracks provide both a physical barrier and secrete saliva, tears, or mucus. All these secretions contain protective proteins like the bacterial cell wall digestive enzyme, lysozyme. Mucus traps microbes and other particles which are removed to the outside or to the stomach. Stomach acidity and digestive enzymes destroy many, but not all microbes.
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Second Line of Defense Microbes that penetrate the first line of defense face the body’s nonspecific (innate), internal second line defense mechanisms. 1. Phagocytosis is the ingestion of invading organisms by certain types of white blood cells (leukocytes) referred to as phagocytes. 2.
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Session 18 (Natural Defense against Disease) - MCB 181...

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