Immune System Quiz

• The immune system has twelve activities related to it.

Nonspecific (Innate) Body Defenses

• The three major elements of the body's nonspecific defense system are the surface membrane barriers, defensive cells such as natural killer cells and phagocytes, and a whole deluge of protective chemicals.
• Lysozyme is found in body secretions such as tears and saliva.
• Fluids with an acid pH are found in the vaginal and stomach secretions.
• Sebum is a product of the sebaceous glands and acts at the surface of the skin.
• Mucus is produced by mucus-secreting glands found in the respiratory and digestive system mucosae.
• During the inflammatory response:
• White blood cells are drawn to the injured area by the release of inflammatory chemicals.
• Tissue repair occurs.
• Local blood vessels dilate, and the capillaries become engorged with blood.
• Phagocytosis of microbes occurs.
• Fluid containing clotting proteins is lost from the bloodstream and enters the injured tissue area.
• Diapedesis occurs.

Column A and B terms

• Have antimicrobial activity: Acids, Lysozyme
• Provide mechanical barriers: Mucosae, Skin
• Provide chemical barriers: Mucus, Sebum
• Entraps microorganisms entering the respiratory passages: Mucus
• Part of the first line of defense: Skin
• Phrases that correctly describe the role of fever in body protection:
• Is a normal response to pyrogens.
• Reduces the availability of iron and zinc required for bacterial proliferation.
• Increases metabolic rate.
• Results from accumulation of fluid leaked from the bloodstream: Edema
• First phagocytes to migrate into the injured area: Neutrophils
• Cellular migration directed by a chemical gradient: Chemotaxis
• Leukocytes pass through the wall of a capillary: Diapedesis
• Walls off the area of injury: Fibrin mesh
• Phagocytic offspring of monocytes: Macrophages

Specific (Adaptive) Body Defenses

• Antigens are substances capable of mobilizing the immune system.
• of all the foreign molecules that act as complete antigens, proteins are the most potent.
• Small molecules are not usually antigenic, but when they bind to self-cell surface proteins, they may act as haptens, and then the complex is recognized as foreign, or an antigen.
• Immunity is resistance to disease resulting from the presence of foreign substances or antigens in the body.
• When this resistance is provided by antibodies released to body fluids, the immunity is called humoral immunity.
• When living cells provide the protection, the immunity is referred to as cellular immunity.
• The major actors in the immune response are two lymphocyte populations, the B cells and the T cells.
• Phagocytic cells that act as accessory cells in the immune response are the macrophages.
• Because pathogens are likely to use both blood and lymph as a means of getting around the body, lymph nodes and other lymphatic tissues (which house the immune cells) are in an excellent position to detect their presence.
• T cells and B cells exhibit certain similarities and differences as can be seen in the following table:
• Originates in bone marrow from stem cells called hemocytoblasts: T cell, B cell
• Progeny are plasma cells: B cell
• Progeny include regulatory, helper, and cytotoxic cells: T cell
• Progeny include memory cells: T cell, B cell
• Is responsible for directly attacking foreign cells or virus-infected cells: T cell
• Produces antibodies that are released to body fluids: B cell
• Bears a cell-surface receptor capable of recognizing a specific antigen: T cell, B cell
• Forms clones upon stimulation: T cell, B cell
• Accounts for most of the lymphocytes in the circulation: T cell.
• An individual receives polio vaccine: Active immunity
• Antibodies migrate through a pregnant woman's placenta into the vascular system of her foetus: Passive immunity
• A student nurse receives an injection of gamma globulin (containing antibodies to the hepatitis virus) after she has been exposed to viral hepatitis: Passive immunity
• This is a "borrowed” immunity: Passive immunity
• Immunological memory is provided: Active immunity
• An individual suffers through chickenpox: Active immunity
• Several important differences between primary and secondary immune response(s) can be observed:
• The initial response to an antigen; gearing-up stage: Primary
• Lag period of several days before antibodies specific to the antigen appear in the bloodstream: Primary.
• Antibody levels increase rapidly and remain high for an extended period: Secondary.
• Immunological memory established: Primary.
• The second, third, and subsequent responses to the same antigen: Secondary.
• Binds with and releases chemicals that activate B cells, T cells, and macrophages: Helper T cell
• Activated by recognizing both its antigen and a self-protein presented on the surface of a macrophage: Cytotoxic T cell
• Turns off the immune response when the “enemy” has been routed: Regulatory T cell
• Directly attacks and lyses cellular pathogens: Cytotoxic T cell
• Initiates secondary response to a recognized antigen: Memory T cell

Test your knowledge of the immune system! Questions cover macrophages, humoral immunity, types of immunity, lymph nodes, immunological memory, inflammatory response, and lysozyme.