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40 Cards in this Set
- Front
- Back
Nonspecific first line of defense against invaders entering through the skin or openings of the body
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Skin and mucous membranes
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Characteristics of the 1st line of defense
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Skin, anti microbial proteins, cilia, gastric juice, and symbiotic bacteria.
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Skin
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A physical, hostile barrier covered with oily and acidic (ph 3-5) secretions from sweat glands.
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Antimicrobial proteins
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Ex: lysozyme. Contained in saliva, tears, and other secretions found on mucous membranes.
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Cilia
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Line the lungs to sweep invaders out
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Gastric juice
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In the stomach; kills most microbes
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Symbiotic bacteria
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Found in the digestive tract and the vagina outcompete many other harmful organisms
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Second line of defense mechanisms
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Phagocytes, complement, interferons, and inflammatory response.
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Phagocytes
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White blood cells that engulf pathogens by phagocytosis. Includes neutrophils and monocytes.
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Monocytes
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Enlarge to form macrophages.
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Natural killer cells
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White blood cells that attack abnormal body cells or pathogen-infected body cells.
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Complement
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A group of about 20 proteins that complement defense reactions. They help attract phagocytes and promote cell lysis.
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Interferons
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Substances secreted by cells invaded by viruses that stimulate neighboring cells to produce defensive proteins.
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Inflammatory response
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A series of nonspecific events occur in response to pathogens. Includes histamine, vasodilation, phagocytes, and complement.
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Histamine
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Secreted by basophils
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Basophils
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White blood cells found in connective tissue
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Vasodilation
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Dilation of blood vessels stimulated by histamine. Causes redness, high temp, and swelling.
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Third line of defense
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Immune response
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Immune response
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Targets specific antigens.
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Antigens
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Molecules that are identified as foreign.
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Major histocompatibility complex (MHC)
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A mechanism by which the immune system is able to differentiate between self and nonself cells
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Lymphocytes
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Primary agents of the immune response. White blood cells that originate in the bone marrow but concentrate in lymphatic tissues.
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Two kinds of lymphocytes
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B cells and T cells
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B cells
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Lymphocytes that originate and mature in the bone marrow. Respond to antigens. Plasma membrane is characterized by antibodies.
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Antibodies
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Specialized antigen receptors. Also called immunoglobulins
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Types of daughter B cells
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Plasma cells and memory cells
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Plasma cells
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B cells that release their specific antibodies which then bind to antigens
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Memory cells
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B cells that do not release their antibodies immediately. Respond to any subsequent invasion of the same antigen. Provide immunity to many diseases after the first occurence of the disease
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T cells
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Lymphocytes that originate in the bone marrow but mature in the thymus gland. Have antigen receptors for recognition of molecules displayed by nonself cells
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Two kinds of T cells
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Cytotoxic T cells/killer T cells and helper T cells
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Cytotoxic T cells/Killer T cells
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Recognize and destroy nonself cells by puncturing them and causing them to lyse
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Helper T cells
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Stimulate the proliferation of B cells and cytotoxic T cells
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Clonal selection
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Results in a proliferation of B cells and T cells that will engage a specific invading antigen
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Two reactions of the immune system response
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Cell-mediated response and humoral response/antibody-mediated response
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Cell mediated response
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Uses mostly T cells and responds to an nonself cell, including cells invaded by pathogens.
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Humoral/antibody mediated response
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Involves most cells and reacts to antigens or pathogens that are circulating in the lymph or blood
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3 supplemental natural body defenses
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Antibiotics, vaccines, and passive immunity
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Antibiotics
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Chemicals derived from bacteria or fungi that are harmful to other microorganisms.
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Vaccines
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Substances that stimulate the production of memory cells.
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Passive immunity
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Obtained by transferring antibodies from an individual who previously had a disease to a newly infected individual
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