Responses of the Immune System Quiz

Explain how the immune system achieves all of the following.

1.       Provides an immediate nonspecific immune response

-          The immune system provides an innate and nonspecific immune response through the skin and mucous membrane, the first line of defense in immune responses.

-          Sweat glads make surface of the skin inhospitable to many microorganisms

-          Mucous membrane will create mucus to trap microbe and other particles

-          Mucus contain lysozyme that disrupts bacterial cell walls 

-          Chemical responses: ciliated epithelium (trap for pathogens), phygocytes (white blood cells that patrol circulatory system and absorb or send enzymes to destroy the pathogens)

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

-          Lymphocytes are the key cells in the immune system, and they are responsible for recognizing antigens.

-          B and T cells recognize antigens by means of antigen-specific receptors embedded in their plasma membranes.

-          B cells produce antibodies, which are specific responses to antigens

-          Phygocytes present antigens to Helper-T Cells, that activates B cells (Humoral Response) and T cells (Cell-mediated Response)

-          B cells differentiate into 2 populations: Plasma cells and memory cells

-          Clonal Selection: Once a specific antigen is presented to B-cells, they began to produce different antigen receptors. Only B cells with reactive antigen receptors are allowed to migrate and divide.

-          T cells differentiate into 2 populations: Cytotoxic T-cells and memory cells

-          Antigen Presentation: To respond to a specific antigen, T-cells must interact with a cell that presents the antigen with its MHC protein marker (all phygocytes, cells infected by specific pathogens and cancer cells)

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

-          The Memory B and T cells activated will remain viable and circulate in lymphatic system in case of a future threat with same type of antigens.

4.       Distinguishes self from nonself

-          Every cell in your body carries a distinctive marker protein that is recognized as “self” and called Major Histocompatibility Complex (MHC)

-          The natural killer cells will not attack the other body cells because all of them carry the same MHC protein marker. 

- Andy Liu '15