Chapter 14: Med Surg Flashcards
immunity
a state of responsiveness to foreign substances such as microorganisms and tumor proteins; fx: defense, homeostasis, surveillance
homeostasis
damaged cellular substances are digested and removed, but the body’s different cell types remain unchanged
surveillance
mutations continually arise, but are normally recognized as foreign cells and destroyed
active immunity
takes awhile to develop, but long lasting
passive immunity
short lived because the host did not synthesize the antibodies and does not retain memory cells for the antigen
antigen
body recognizes a foreign substance and elicits an immune response; most composed of protein
thymus gland
central (primary) lymphoid organ- shrinks with age and is important in the differntiation and maturation of t lymphocytes
bone marrow
central (primary) lymphoid organ- produces RBCs, WBCs, and platelets
lymphoid tissue
found in submucosa of the respiratory, genitourinary, and GI tract- protects body surface from external microorganisms e.g. tonsils
spleen
primary site for filtering foreign substances from blood and major site of immune responses to blood-borne antigens
lymphnodes
filtrate foreign material brought to site and circulate lymphocytes
mononuclear phagocytes
monocytes & macrophages; capture through phagocytosis and the macrophage bound antigen is presented to lymphocytes which triggers an immune response
B lymphocytes
produced in bone and differentiate into plasma cells which produce antibodies (immunoglobulins)
T lymphocytes
migrate from bone marrow to thymus, compose 70%-80% of lymphocytes and provide immunity to intracellular viruses, tumor cells, and fungi; long term immunity
T cytotoxic cells
CD8 attack antigens on cell membrane of foreign pathogens and destroy, antigen specific and sensitized by exposure to the antigen
T helper cells
CD4 regulate cell-mediated immunity and the humoral antibody response
natural killer cells
involved in cell-mediated immunity, large lymphocytes, do not require prior sensitization for activation, recognize and kill virus-infected cells, tumor cells, and transplanted grafts
antibodies
immune globulins produced by lymphocytes in response to antigens
dendritic cells
capture antigens at sites of contact with the external environment and then transport the antigen to a T cell with specificity for the antigen and activate the immune response
cytokines
soluble factors secreted by WBCs that act as messengers between cell types and instruct cells to alter their proliferation, differentiation, secretion, or activity
interferons
type of cytokine that help the body’s natural defenses attack tumors and viruses and enhance natural killer cells
what is the first antibody formed by humoral immunity?
IgM formed by the primary immune response (4-8 days after initial exposure); forms antibodies to ABO blood antigens
cell-mediated immunity
t cells. macrophages, and natural killer cells that are initiated through specific antigen recognition by t cells; memory cells- protects against fungus, intracellular viruses, chronic infections, and tumor cells
humoral immunity
antibody-mediated immunity produced by b lymphocytes that have memory cells- protects against bacteria, extracellular viruses, respiratory pathogens, and GI pathogens