Biology: Chapter 8: The Immune System Flashcards
What is Innate Immunity
Immune defenses that are always active and non specific; no immune memory
What is Adaptive Immunity
Composed of Defensives that take time to activate but target a specific invader and have immune memory
How is bone marrow related to the immune system
immune cells are released from bone marrow
How is the spleen and lymph nodes related to the immune system
sites where immune responses can be mounted and where B cells are activated
How is the thymus related to the immune system
site of T cell maturation
What are Gut Associated Lymphoid Tissue
tonsils and adenoids
What is the non specific immune system
skin, defensins, mucus, lysozyme, stomach acid, stomach bacteria, complement, interferons
What are defensins
antimicrobial compounds secreted by the skin
what is the complement system
punches holes in the cell walls of bacteria
What are interferons
given off by virally infected cells and help prevent viral replication and dispersions to nearby cells
What are macrophages
ingest pathogens + present major histocompatibility complex + secrete cytokines
what is MHC-1
present in all nucleated cells; displays endogenous antigens for cytotoxic T cells
what is MHC-2
present in professional antigen presenting cells; displays exogenous antigen to helper T cells
what are professional antigen presenting cells
macrophages, dendritic cells, some B cells, and certain epithelial cells
what are dendritic cells
antigen presenting cells in the skin
what are natural killer cells
attack cells that down-regulate MHC (virally infected or cancer)
what are the granulocytes
neutrophils, basophils, eosinophils
what are neutrophils
ingest bacteria, especially opsonized bacteria (marked with antibodies); follow bacteria using chemotaxis
what are eosinophils
used in allergic reactions and invasive parasitic infections; release histamine
what are basophils
used in allergic reactions (i.e. mast cells)
what is humoral immunity
centered on antibody production by plasma cells which are activated by B cells
What is an antibody
target a particular antigen
what is the structure of an antibody
contain two heavy chains and two light chains; have a constant region and variable region; tip of variable region is the antigen binding region
What happens when antibodies are activated
the antigen binding region undergoes hypermutation to improve the specificity of the antibody produced; may be given signals to switch isotypes (IgM, IgA, IgG. etc)
What happens when an antibody binds to an antigen
1) opsonize pathogens (mark for destruction)
2) Agglutination into insoluble complexes to be ingested or neutralized
what are memory B cells
lie in wait for a second exposure to a pathogen and can then mount a more rapid and vigorous immune response
what is cell mediated immunity
centered on the functions of T cells
How do T cells mature
undergo maturation the thymus; go through positive selection (T cells that react to antigens) and negative selection (apoptosis for self reactive T cells)
What are helper T cells
CD4+ respond to antigens on MHC-II and coordinate immune response; secrete lymphokines and Th1 and Th2 cells
what are Th1 cells
secrete interferon gamma for activation of macrophages
what are Th2 cells
activate B cells
what are cytotoxic T cells
CD8+ respond to antigens on MHC-I and kill virally infected cells
what are suppressor T cells
tone down the immune response after infection and promote self tolerance
what are autoimmune conditions
self-antigen is identified as foreign and the immune system attacks bodies own cells
what is an allergic reaction
nonthreatening exposures incite inflammatory response
what is active immunity
vaccination; activation of B cells to produce antibodies to an antigen
what is passive immunity
transfer of antibodies to an individual; mother to baby
what is the lymphatic system
circulatory system that consists of one way vessels with intermittent lymph nodes
how does the lymphatic system connect to the cardiovascular system
via the thoracic duct in the posterior chest
What is the function of the lymphatic system
equalizes fluid distribution, transports fats and fat soluble compound in chylomicrons, and provides sites for mounting immune responses
