Immune System Quiz

1.    Provides an immediate nonspecific immune response

a.     The innate, or nonspecific, response immunity is the defense in which humans are born with, protecting them against harmful antigens. It involves barriers including secretory molecules and cellular components. The innate immune system also acts as the first line of defense, present and ready to be action against intruders upon infection. It is not antigen specific and responds equally to a variety of harmful substances without tracking any biological memory of the harmful antigen. Some examples of the nonspecific immune response include the cough reflex, enzyme in tears and skin oils, mucus (traps bacteria and small particles), skin, and stomach acid. It includes the integumentary system (skin/mucus), respiratory system (trachea/nasal passages/lingings) , and digestive system (stomach acids and enzymes.

               

2.    Activates T and B cells in response to an infection

a.     Most of the immune system consists of white blood cells. White blood cells vary in many different types and of those types, the two most prominent are the lymphocytes (T Cells and B Cells). T cells (help activate B cells to divide into plasma cells, call in phagocytes to destroy microbes, and activate killer T cells)  are critical to the immune system and help destroy infected cells and stimulate overall immune response. The T cell possesses a molecule on the surface (T-cell receptor) that interacts with molecules called MHC (major histocompatibility complex). MHC helps the T cell recognize harmful antigens and is also on the surface of most other cells in the body. B cells have the ability to recognize free floating antigens, make antibodies that bind to antigens, and mark the antigen for destruction by cells from the immune system.  B cells can differentiate and produce into antibody. However, they rely on T cells to provide to signal to begin maturation. Once the signal is sent, the B cells produce plasma which in turn secretes large amounts of antibodies.

3.    Responds to a later exposure to the same infectious agent

a.     The adaptive immune system, the specific immune system, acts as second line defense after the innate immune system response and also provides protection to re-exposure to the same infectious agent. Unlike the innate immune system, the adaptive immune system requires some time to react against the invading organism. The adaptive immune system is also antigen specific and reacts only with the organism that induced the response. The adaptive immune system also demonstrates immunological memory, “remembering” (Portion of T and B cells differentiate into memory cells to quickly respond to the same antigen) that it has encountered the invading organism, reacting exponentially faster to the same exposure. Doctors take advantage of this memory to artificially induce defense against an antigen via vaccination.

4.    Distinguishes self from nonself

a.     Every body cell carries distinctive molecules that identifies itself.  The body’s immune system does not usually attack tissues that carry the self-identifying marker. It coexists with other body cells in a state called self-tolerance. When the immune system detects cells or organisms that carry “foreign” molecules, it immediately acts against them. Any tissue or cells from another individual (except from an identical twin) are rejected. This is why patients who taken on transplants must take anti-rejection medicine. The body will even reject proteins unless it is first broken down into its primary non-antigenic building block form. The body detects foreign objects by epitopes which protrude from the surface of the foreign organism. In abnormal situations, however, the immune system may misidentify itself as a foreign substance and carry an immune attack on it. This response is called autoimmune disease. Allergies occure because the immune system is being triggered (cat fur, pollen, etc.) to set off a response.