I M M U N I T Y Flashcards
functions of lymphatics and lymph nodes
- filtration & immune system activation
- defend body against environmental hazards & internal threats
- immunological recognition
- immune effector functions
- immune suppression
- immunological memory
where does the lymph return to the circulatory system?
- right lymphatic duct
2. thoracic duct
what mechanisms keep lymph flowing through the lymph valves?
- mini valves
- pulsations of nearby arteries
- contraction of smooth muscle in walls of lymphatic vessels
- breathing
- pumping of skeletal muscles
what major cell type is in the red pulp of the spleen?
RBCs & blood borne pathogens
what major cell type is in the white pulp of the spleen?
lymphocytes
describe the non-specific defense, fever
- abnormally high body temperature in response to invading microorganisms
- the body’s thermostat is reset upward in response to pyrogens, chemicals secreted by leukocytes and macrophages exposed to bacteria and other foreign substances
- IL-1 is secreted by macrophages and stimulates hypothalamus to increase temperature set point (called endogenous pyrogen)
describe the non-specific defense, complement
- system of circulatory proteins that assist antibodies in destruction of pathogens
- links innate and adaptive immunity
- amplifies inflammatory response
- membrane attack complex: pore in cell and lyse cell
describe the non-specific defense, interferon
chemical messages that coordinate the defense against viral infections/inhibit viral replication
- virus enters cell and nucleus to replicate (cell is later killed by virus)
- interferon genes switch on
- cell produces interferon molecules
- interferon binding stimulates cell to turn on genes for antiviral proteins
- antiviral proteins block viral production
what changes (or 4 cardinal signs) would occur as a result of inflammation due to histamine increasing blood flow and permeability of blood vessels?
arteriole dilation & local hyperemia
- heat
- redness
increased capillary permeability > capillaries leak fluid (exudate - protein-rich fluid)
- pain
- swelling
MHC 1
displayed by all nucleated cells
recognized by CD8 (cytotoxic T cells)
endogenous antigens
MHC 1 + IL-1 > cytotoxic T cells
(phagocytes, performs, granzymes)
MHC 2
displayed by all APCs (antigen-presenting cells)
recognized by CD4 (helper T cells)
exogenous antigen
APC w/ antigen displayed on MHC 2 + CD4 T cell + B7 to CD28 > T helper cells & T memory cells
how are B cells activated?
B cells are activated by T helper cells + IL-2 > memory B cells and plasma cells
describe an antibody
antigen binding site: variable regions of light and heavy chains
variable region: determines what the antigen binds to
constant region: determines class of antibody
what defense mechanisms do antibodies use to prepare antigens for destruction?
- neutralization
- agglutination
- precipitation
define HIV & discuss its mechanism of infection & its specific target cells
HIV: Human Immunodeficiency Virus
targets CD4 cells via surface proteins/ destroys T helper cells; inject RNA > DNA (reverse transcriptase), DNA > genotype > DNA provirus > viral DNA & proteins that spread
where does HIV reside during the asymptomatic period?
inside helper T cells
after activation, what are the killing actions of cytotoxic T cells (Tc)
directly attack and kill other cells
perforin and granzymes to cause apoptosis
enhance phagocytosis
describe innate immunity
- non-specific
- always present
- physical barriers (skin, mucous)
- phagocytes
- immune surveillance
- interferons
- complement
- inflammation
- fever
describe adaptive immunity
(acquired)
- specific lymphocytes
- specific
- B & T cells
- inducible
define active humoral immunity & artificial/natural elements
when B cells encounter antigens and produce antibodies against them
artificial: vaccine
natural: infection
define passive humoral immunity & artificial? natural elements
instead of being made by plasma cells, ready-made antibodies are introduced into body > B cells not challenged by antigens, immunological memory does not occur, and protection provided by borrowed antibodies ends when they degrade in the body
artificial: injection
natural: placenta
humoral immunity definition
B cells; soluble antibodies, simple, interact in extracellular
cell-mediated immunity definition
T cells: recognize and respond to processed fragment of antigen displayed on cell surface, cell to cell interaction, intracellular abnormal or foreign infected cells
major function of interleukins
IL-2: stimulates fever and is released by macrophages to stimulate T cells to release IL-@ and synthesize more IL-2 receptors
stimulate T cell divisions, attract/stimulate macrophages, attract and stimulate NK (natural killer) cells, promote activation of B cells
describe in correct order the sequence of events that leads to activation of cytotoxic T cells and the cell-mediated immune response
MHC1 + CD8 + (co-stimulate) IL-2 > cytotoxic T cells > perforins and granzymes
perforins definition:
insert in target cell membrane to form a pore (cell can’t maintain homeostasis)
granzymes definition
enter target cell through pore and release enzymes that degrade cell
what happens to our immune system as we age?
it slows down
primary immune response details
- activation and differentiation of B cells
- lag time of 3-5 days before increase in plasma antibodies
- plasma antibodies peak within 10 days and then decline quickly
secondary immune response details
- faster and more effective than primary
- memory cells are present and primed for attack
- new plasma cells are generated within hours
- plasma antibodies peak at high levels within 2-3 days
- plasma antibodies bind more tightly to their antigen
- plasma antibodies stay elevated for longer
