Exam 2 (Ch. 21) Flashcards
first line of defense
external body membranes (skin & mucosa)
second line of defense
antimicrobial proteins, phagocytes and other cells
-phagocytes, NK cells, inflammatory response, antimicrobial proteins & fever
third line of defense
B and T cells; attacks specific foreign substances
what are the 3 stages of an inflammatory response
stage 1: inflammatory and chemical release
stage 2: vasodilation and increase vascular permeability
stage 3: phagocyte mobilization
what occurs during stage 1 of the immune response
chemicals are released into ECF by injured tissues or immune cells
what occurs during stage 2 of the immune response
-vasodilation causes hyperemia (congestion with blood) that leads to redness and heat
-increased capillary permeability causes exudate (fluid containing clotting factors and antibodies) to leak into tissues and cause swelling
what occurs during stage 3 of the immune response
neutrophils flood the area first, followed by macrophages
four cardinal signs of inflammation
(1) redness
(2) heat
(3) swelling
(4) pain
what are the benefits of inflammation
-prevents the spread of damaging agents to nearby tissues
-disposes of cell debris & pathogens
-alerts the adaptive immune system
-sets the stage for repair
Molecules that make up the complement system and where would you find these molecules
consists of 20 blood proteins that circulate in blood in their inactive form
-includes proteins C1-C9, regulatory proteins and factors B, D & P
Different pathways that activate the complement system
(1) classical pathway
(2) lectin pathway
(3) alternative pathway
three different outcomes once the complement system is activated
(1) enhances inflammation
(2) promotes phagocytosis
(3) causes cell lysis
Characteristics of adaptive immunity
specificity- recognizes and targets specific antigens
systemic- not restricted to the initial state
memory- mounts an even stronger attack to known antigens upon repeated exposure
which lymphocyte activates humoral immunity
B cells
which lymphocyte activates cellular immunity
T cells
what occurs during humoral immunity
antibodies produced by B lymphocytes circulate freely in body fluids and temporarily bind & inactivate an extracellular target, marks them for destruction
what occurs during cellular immunity
T cells directly (kill infected cells) or indirectly (release chemicals to enhance inflammation or activate lymphocytes/macrophages) kill cancer cells or cells infected by a microbe
2 major population of T cells
(1) CD4 cells (helper/regulatory)
(2) CD8 cells (cytotoxic)
Cell surface markers that define each T cell population
CD4 glycoproteins- helper and regulatory T cells
CD8 glycoproteins- cytotoxic T cells
which T cells activate B cells or other T cells and macrophages; direct the adaptive immune response
Helper T cells
which T cells destroy cells with foreign antigens
Cytotoxic T cells
which T cells respond to class I MHC proteins
CD8
which T cells respond to class II MHC proteins
CD4
which T cells slows or stops activity of the immune system by secreting inhibitory cytokines and transforming factor growth beta
regulatory T cells
which T cells control autoimmune diseases; suppress self-reactive lymphocytes
regulatory T cells
helper t cell that mediates most aspects of cell immunity
TH1
helper t cell that defends against parasitic worms, mobilizes eosinophils, activates responses dependent on humoral immunity and promotes allergies
TH2
helper t cell that links adaptive and innate immunity by releasing IL-17
TH17
substances that can mobilize adaptive defenses and provoke an immune response
antigens
what are antigens
mostly large, complex molecules not normally found in the body (foreign intruders/ non-self)
two important functions of complete antigens
(1) immunogenicity - the ability to stimulate specific lymphocytes to proliferate
(2) reactivity - the ability to react with the activated lymphocytes and the antibodies released by immunogenic reactions
antigenic determinants
parts of the antigen that antibodies or lymphocyte receptors bind to
what are the two processes associated with lymphocyte education
(1)positive selection - selects T cells capable of recognizing self MHC proteins
(2) negative selection- t cells that bind to self-antigens displayed by self MHC undergo apoptosis
what is the purpose of positive and negative selection
immunocompetence
and self-tolerance
proteins released from virus infected cells & certain lymphocytes that acts as chemical messengers to protect uninfected cells from viral infection and mobilize the immune system
interferons
IFN- alpha and IFN-beta
enter neighboring cells to stimulate production of proteins that block viral production and degrade viral RNA; activate NK cells
IFN-gamma
secreted by lymphocytes and activates macrophages
cell proliferation after the first exposure to an antigen
primary immune response
re-exposure to the same antigen that gives faster, more prolonged and more effective response
secondary immune response
which immune response;
-has a lag period of 3-6 days for antibody production to begin
-peak levels of plasma antibody are reached in 10 days
-antibody levels then decline
primary
which immune response;
-has sensitized memory cells
-antibody production is immediate with peak levels in 2-3 days at much higher levels and with greater affinity
-high antibody levels for weeks to months
secondary
humoral immunity that occurs when B cells naturally encounter antigens and produce specific antibodies against them
Active humoral immunity
humoral immunity that occurs when ready made antibodies are introduced into the body, B cells are not activated by the antigen and immunological memory does not occur
passive humoral response
how do humans acquire naturally acquired active immunity
formed in response to bacterial or viral infection
how do humans acquire artificially acquired active immunity
vaccines
how do humans acquire naturally acquired passive immunity
antibodies delivered to fetus via placenta, or to infant via milk
how do humans acquire artificially acquired passive immunity
injection of serum such as gamma globulin
what are the two benefits of vaccines
(1) weakend antigens provide functional antigenic determinants that are both immunogenic and reactive
(2) spare us from symptoms
what is in a vaccine
pathogens that are dead or attenuated or their components; mRNA that codes for a viral protein
how are antibodies produced
secreted in response to an antigen by plasma cells
4 mechanisms of antibody action
(1) Neutralization
(2) agglutination
(3) precipitation
(4) component fixation
