Immune System
Non-Specific Immunity Lysozyme – digests cell walls Skin (physical barrier) Stomache Acidity Phagocytes (roam body for bacteria/dead cells) Macrophages (long lived, generate toxic forms of oxygen) Neutrophils (60-70% of white blood cells, self destruct) Complement Protein (coats cells to attract phagocytes) Inflammation Histamine (initiates inflammation) Causes increased blood flow and increased permeability to the injured tissue.
Specific Lymphocytes (produced from stem cells) T cells Mature in thymus 2 types, Helper T cells and Cytotoxic T cells Cytotoxic T’s involved in cell-mediated immunity B cells Mature in bone marrow 2 Types, plasma cells and memory B cells. Plasma Cells Factories that produce antibodies (Humoral immunity) Memory B cells (secondary immune response) Recognize old invaders and produce antibodies immediately. (produces in a much larger concentration than in primary response. Primary Immune response Helper T’s help activate B cells; T cells recognize foreign antigens on surface of phagocytic cells and bind to them. After binding they multiply and pump chemical signals to bring B cells.
Cell-mediated immunity Cells infected with viruses produce viral antigens. Some appear on the cell surface. Cytotoxic cells recognize these and destroy them. Class I histocompatability antigens (MHC) All cells within a person’s body have this (except red blood cells), anything the immune system finds that doesn’t have a matching MHC registers as foreign. Class II histocompatability antigens are on immune cell. Play a role in immune cell communication. Every B cell has a specific antigen recognition site on its surface. B cells patrol the body for a particular invader. When a B cell meet and attaches its appropriate antigen, it activates and the B cell undergoes mitosis and differentiation into plasma cells and memory cells.
Antibodies (Humoral Immunity) 2 ends; Fragment antigen binding region (Allows antibodies to recognize specific antigens), 5 types of antibodies for different cells types (IgA, IgD, IgE, IgM, IgG) Ig=immunoglobulin; Other end binds to effector cells. Epitope (Small accessible portion of antigen) Forms of attack Neutralization Binds and blocks Opsonization Enhance macrophage attachment to microbes Agglutination (Clumping) Combines both processes
Complement Fixation (Disposal) Proteins cause viruses and pathogenic cells to lyse so that they may be cleaned. Membrane attack complex (MAC) 2 Paths Classic Pathway The lysing is caused by antibodies Alternative pathway The lysing is caused by already present substances.
Active Immunity Depends on the response of a person’s own immune system. (Ex. Vaccine) Passive Immunity Transfer of one person’s antibodies into another person. (Temporary)
Blood Types ABO blood groups Rh Factor A blood has a antigens on surface, B has B, and O has none. Rh Factor Produces IgG antibodies which produce memory cells. Causes a problem in pregnancies when a mother is negative and children are negative, especially after the first born.
Allergies Hypersensitive responses to environmental antigens. Induces in mast cells to degranulate (release histamine and inflammatory agents.) Anaphylactic shock Widespread mast cell degranulation, triggers dilation of peripheral blood vessels, and causes a significant drop in blood pressure.
Immunodeficiency diseases SCID (Severe combined immunodeficiency) Cell mediated and humoral immune defenses fail AIDS Collapses immune system by targeting and destroying helper T cells and its coreceptor fusin, which is also found on macophages. Chemokins Suppress HIV-1 infection by blocking the receptors that HIV bind to. Moods release hormones that may impair or enhance immunity