immune system 3rd line of defense Flashcards
immune system
recognizes specific invaders more efficiently than nonspecific. it has extreme efficiency, memory, and a prompt response to second exposure to an antigen. it can amplify inflammatory and complement responses
antigen
any molecule that elicits an immune response (virus, bacteria, mold, etc)
antibody
the system responds to an antigen by producing a specific type of antibody that attaches to the antigen and helps counter the effects
immunity
refers to the resistance to specific invaders
acquired immunity
immunity gain after experience
active immunity
gained from exposure / vaccinations
passive immunity
passed from mother to child (can pass through placenta or milk)
2 types of lymphocytes
B cells and T cells
B cells
mature in bone and release antibodies that function when dissolved in blood and have memory
how antibodies function
(they are proteins specific to one antigen) attach to antigen flagging them and having a macrophage of complement destroy it
5 classes of antibodies
IgA, IgD, IgE, IgG, IgM
each has specific activity
plasma cells (effector cells)
B cell responsible for creating and secreting antibodies, only live a few days, but can make about 2000 Ab/second
memory cells
long lived B cells that respond quickly to a subsequent invasion by the same antigen
clonal selection theory
B cells can randomly rearrange the variable regions of an antibody until a match is made for a new antigen. involves primary and secondary immune response
primary immune response
when B cells find a match for an antigen, plasma cells are produced that make a new antibody
secondary immune response
B cell makes memory cell to deal with antigen if it appears again
T cells
originate in bone marrow and mature in thymus (above heart). they identify non self cells and create 2 kinds of daughter cells
T cytotoxic
(killer) - drills holes into pathogen infected cells
T helper
It is kind of nark cell that tattles on the antigens that are presented by macrophages. Macrophages will engulf an antigen and present some if its proteins on its cell membrane. T helper sees this and starts calling for the B cells, more macrophages and T cytotoxic cells.
humoral immunity
(humors = body fluids, always involves serum and the action of Ab) defense against
bacteria and viruses free in the blood or extra cellular fluid. B cells have responded to antigens and have produced plasma cells and memory cells. Cell surfaced antigens with antibodies bound to them will be destroyed by phagocytes or trigger T cells. Protects against: viruses, bacteria and toxins in the body fluid.
cell mediated immunity
defense mounted by T cells against bacteria and viruses inside of body cells, against fungi and protozoans, and against cancer cells. T cells promote phagocyte activity, Antibody
secretion by B cells. Protects against: bacteria and viruses within host cells. It is also responsible for transplant rejection.
antibody antigen complexes can be eliminated by several mechanisms:
- binding can physically neutralize antigen making them harmless
- agglutination reactions cause cells/viruses to clump, which makes it easy for phagocyt es to capture and engulf them
- they can activate complement proteins