Test 2 Notes #2

Test 2 Notes #2 - 3.2.10 Chapter 43: Defense against...

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3.2.10 Chapter 43: Defense against disease: The Immune system 1. Three lines of defense against microbial attacks a. Innate Defenses i. Non-specific external barriers-mucus membranes, stomach, and skin. Lining inside of stomach and throat are epithelial cells that secrete mucus. Skin-presents a physical barrier to microbial entry. Skin is dry and dead cells comprise the surface making it an inhabitable place for microbes to live. Mucous membranes-Sweat/sebaceous glands secrete acids & natural antibiotics like lactic acid. Mucous membranes of respiratory and digestive tracts are well defined. Secretions have antibacterial enzymes. Stomach-if microbes are swallowed; acids and protein-digesting enzymes destroy them. ii. Non-specific internal defenses-fever, inflammation, phagocyte and natural killer cells. Phagocytic cells- white blood cells (WBCs) in extracellular fluid, amoeboid shape, destroy microbes by phagocytosis. Natural killer cells- WBCs that destroy cells infected by viruses and cancerous cells by punching holes in them. Inflammatory response-caused by large-scale microbial invasion through wound. Damaged cells release histamine. Histamine increases blood flow and “washes” out the wound. It also makes blood vessels more permeable, allowing WBCs to pass more easily to the site of microbial invasion. Inflammation (red, swollen, and warm). Wounded cells release chemicals and other cells called macrophages, WBCs that engulf bacteria, dirt, and tissue debris, receive the distress signal and come to clean up. Mast cells receive information that injury has taken place and release histamine. b. Acquired Immunity-specific immune response i. B cells (bone-humeral immunity) and T cells (cell mediated immunity kills target cells immediately) provide two different types of cellular immune response. B cells attack viral or bacterial microbes anywhere in the body. When the virus infects its target cells, T cells step in. The helper T cells are the group of cells in-between the B and T cells. B cells response Step 1. Recognize/identify the invader. Antibodies are proteins produced by a host to bind to and inactivate foreign particles. Made by B cells and are unique to binding site so they can only bind to one antigen. Antigen- antibody generating/the invader/the foreign entity. Binding of antigen triggers the immune response. Genes for antibody parts recombine during development-the result is a random assortment of antibodies; during development some of these cells will bind to the bodies own proteins. If an antigen from a particular B cell binds to your bodies’ own proteins, that B cell is removed from your body before birth. Immune system distinguishes “self” from “non-self” by retaining only those immune cells that do not respond to the body’s own molecules. Examples of autoimmune disorders include early onset diabetes. Insulin producing cells in the pancreas (islets of Langerhans) are destroyed and as a result the body cannot produce
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insulin. The body randomly makes over 100,000,000 different antibodies.
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This note was uploaded on 05/12/2011 for the course BIOL 1202 taught by Professor Gregg during the Spring '08 term at LSU.

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Test 2 Notes #2 - 3.2.10 Chapter 43: Defense against...

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