Flashcards in Immune System Deck (60):
Body's ability to resist or eliminate potentially harmful foreign materials or abnormal cells
Identifies and destroys abnormals cells that arise in the body
Nonspecific, defends against any foreign or abnormal material, even on initial exposure, responds immediately
innate defense system
Specific, selectively targets particular foreign material to which body has already been exposed, takes more time to mount
Adaptive defense system
First line of defense
epithelial barriers (skin and mucosa membranes)
Second line of defense
internal defenses (inflammation)
Third line of defense
List all factors of second line of defense
fever, phagocytes, NK cells, antimicrobial proteins, and inflammation
What are the 2 types of phagocytes?
neutrophils and macrophages
Lymphocytes that nonspecifically destroy virus-infected cells and cancer cells, kill by direct contact
What is the purpose of inflammation?
isolate, destroy, or inactivate invaders, remove debris, and prepare for subsequent healing and repair
What are the four cardinal signs of acute inflammation?
redness, heat, swelling and pain
What are the sequence of events?
release of inflammatory chemicals, vasodilation and increased capillary permeability and phagocyte mobilization
In area of tissue damage release histamine that cause localized vasodilation and increased capillary permeability
What causes redness and heat
arterioles dilate and increase blood flow
What causes swelling and pain?
increased capillary permeability so fluid and plasma proteins leak into tissue spaces
In order, what are the 4 steps of phagocyte mobilization?
Neutrophils migrate up gradient of chemotaxins to injury site
Neutrophils stick to endothelial lining
Neutrophils squeeze between endothelial cells
Increase in number of neutrophils in blood response to ____- inducing factors
What follows neutrophils?
monocytes which become macrophages
What are the components of pus?
mixture of living and dead phagocytes, dead tissue and bacteria
Secreted by virus-infected cells, interfere with replication of viruses in nearby cells that have not yet been infected
What are the 2 ways that complement proteins can be activated?
Innate: by exposure t carbohydrate chains present on surfaces of microorgansims
Adaptive: by exposure to ABs produced against a specific foreign invader
What are the 3 effects of activated complement?
enhances inflammation, oposinzation and cell lysis, MAC complex
Abnormally high body temperature, release of pyrogens
What are the 2 benefits of fever?
causes liver and spleen to sequester iron and zinc (less available for bacterial growth)and increases metabolic rate of tissue cells (speeds up repair)
What type of immunity acts against extracellular and provides by antibodies present in body's fluids?
What type of immunity acts against intracellular and provided by living cells?
large, complex molecule that triggers a specific immune response against itself when it gains entry into the body
What type of cells are involved in humoral? Cell-mediated?
Humoral: B cells
Cellular- T cells
Where do B and T cell originate?
red bone marrow
Ability to recognize a specific AG by binding to it
Failure to respond t self-AGs
What are the primary lymphoid organs?
thymus and bone marrow
What are secondary lymphoid organs?
spleen, lymph nodes, and peyer's patches
What are the 2 options B cells can become during clonal expansion?
PCs and memory cells
Describe primary immune response
occurs on first exposure to a specific Ag, 3-6 days, peak plasma AB levels reaches in 10 days
Describe secondary immune response
occurs on re-exposure to same Ag, memory cells respond within hours
Active humoral immunity
B cells encounter Ags and produce Abs against them
What type of immunity is a response to infection
Active humoral, naturally acquired
What type of immunity responds to vaccine containing dead or attenuated pathogens?
Active humoral, artificially acquired
Passive humoral immunity
ready-made ABs introduced into body
What type of immunity has Abs delivered to fetus via placenta or to infant through milk?
Passive immunity, naturally acquired
What type of immunity has an injection of Abs from immune donor?
Passive immunity- artificially acquired
Proteins secreted by PCs in reponse to an Ag, capable of bindning specifically with that Ag
What are the four defensive mechanisms?
4. Complement fixation
Abs block specific sites on viruses or bacterial toxins; prevents binding to receptors on tissue cells
Abs bind to target cells membrane
Soluble molecules are cross-linked
Abs bind to more than once cell-bound Ab at a time
Activated by a foreign Ag only when it is on the surface of a cell that also carries a self-Ag
What are the 3 APCs?
B cells, macrophages, and DCs
What type MHC do CD8s bind?
What type of MHC do CD4s bind?
Found on surface of all nucleated cells; display endogenous Ag
Found only on surface of APCs; display of exogenuos Ag
Release perforin and granzymes
NK cells and CD8