Human Biology: Immunity 2023 with verified questions and answers

The Immune System recognizes specific foreign molecules, functions to protect us from disease Components of the Immune System lymphoid organs, red bone marrow, white blood cells Basic Immunology depends on its ability to distinguish between "you" and "not you" Autoimmunity an immune reaction against self molecules Antigens class of non-self molecules, "antibody generators". Defined as substances that bind to specific immune receptors and elicit an immune response Non-specific mechanisms of immunity same response every time no matter what the pathogen is Stomach pH acidic Tears and mucous pH basic Complement group of proteins released by the liver which attack bacteria Interferons group of proteins released by viral infected cells; help uninfected cells resist infection and produce membrane blocks Inflammation tissue response to injury, increased blood flood to the site of injury, restricted from leaving; results in clotting/swelling Phagocytosis monocytes/macrophages and neutrophils get rid of bacteria. eosinophils get rid of clots and antigen-antibody complexes Histomines chemicals released by injured body cells that begin the inflammatory response Inflammatory Response capillaries dilate; pyrogens released, reach hypothalmus, temperature rises; pain receptors activate; WBC's flock to infected areas like sharks to blood Specific mechanisms of immunity responses tailored to a specific pathogen - produced by lymphocytes, recognize foreign proteins and destroy them Cell-mediated immunity T-lymphocytes attack by attaching to bacteria membrane and punching holes through them. T-cells also attack viral-infected cells in the same manner Antibody mediated (Humoral) immunity B-lymphocytes produce antibodies (specifically the plasma B-cells). Memory B-cells "jump start" the specific immune response to a pathogen on later exposure. Humoral immunity time Can take up to 3 weeks for the FIRST immune response to kick in. This is why botulism can kill someone in a week. Exception to being sensitized to antigens blood transfusion reactions Antibody mechanism bind to antigens on bacteria, viral-infected, or blood cells; cause cells to clump together. DOES NOT kill the cells; must wait for eosinophils to phagocytize the antigen-antibody complexes Artificial Immunity (vaccines) injected with either the inactive pathogen or closely-related pathogen; produce b-cells, antibodies, memory B/T cells against the pathogen's antigens. e.g, using cow pox to prevent small pox Passive Immunity injected with antigens against same pathogen - SHORT TERM - no memory cells produced. e.g, tetanus shot Allergies over stimulation of the immune system, one class of antibodies (IgE in tissues) produces allergic reactions. Allergy shots active immunity, injected with the allergen; produce antibodies (IgG in blood) that attack allergens Types of Lymphocytes T-cells (Thymus), B-cells (bone marrow), NK (natural killers) T-cells 80% of circulating lymphocytes Cytotoxic T-cells T-ck: attack foreign cells or body cells infected by viruses (cell-mediated immunity) Natural Killer T-cells T-nk: 5-10% of circulating lymphocytes, attack foreign cells, normal cells infected with viruses, and cancer cells that appear in normal tissues. Known as "immunologic surveillance" Memory T-cells produced by the division of activated T-cells following exposure to a particular antigen and remain on reserve to be reactivated following later exposure Regulatory T-cells Helper T-cells (T-h) and Suppressor T-cells (T-s) control activation and activity of B-cells respectively Helper T-cells (T-h) recognize antigens, activate B-cells (plasma + memory), activate other T-cells, synthesize and release B-cell growth factor (BCGF) and T-cell growth factor (TCGF) B-cells 10-15% of circulating lymphocytes, can differentiate into plasmocytes (plasma B-cells) when stimulated by exposure to an antigen Plasma B-cells produce antibodies: soluble proteins that react with antigens, also known as immunoglobulins (Igs) Memory B-cells produced by the division of activated plasma B-cells following exposure to a particular antigen (remain on reserve to be reactivated later) B-lymphocytes can respond to millions of foreign antigens; this capability exists before exposure to any antigens Antibodies circulate in blood plasma and lymph, bind to pathogens expressing the antigen and mark them for destruction by complement activation or for uptake and destruction by phagocytes CMI vs. Humoral CMI: direct attack by activated T-cells Humoral: attack by circulating antibodies, released by the plasma cells derived from activated B-cells