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gives examples of innate defenses?
- surface barriers (skin, mucous membranes)
- phagocytes (WBC)
- NK cells (immunological surveillance)
- antimicrobial protein (interferons)
what are some adaptive defenses?
- cellular immunity
- humoral immunity
describe phagocyte mobiliziation
- leukocyosis: neutophils enter blood from bone marrow
- margination: neutophils cling to capillary wall
- diapedesis: neutophils faltten and squeeze out of capillaries
- chemotaxis: neutrohpils follow chemical trail
what is interferon
- IFN enter neighbor cells to warn them (tell them to produce proteins that block viral reproduction and degrade viral RNA)
- activate NK and macrophages
- classical pathway (activated by antibodies coating the target cell)
- lectin pathway: activated by lectins binding to specific sugars on microorganism's surface
- alternative pathway: activated spontaneously; lack of inhibitors on microorganism's surface
- Membrane Attack Complex (MAC): insert into target cell and create pores that lyse target cell
coats pathogen surfaces, which enhances phagocytosis after system complements
what is the purpose of the inflammatory response?
repair and prevent the spread of damaging agents
how does inflammatory response begin?
chemicals released in ECF by injured tissues, immune cells, and blood proteins
whats the difference between phagocytosis of pathogens by neutrophils and macrophages
neutrophils are short term while macrophages are ong term
release of inflammatory chmeicals prompts what kind of responses?
- arterioles dilate, local hyperemia (increased blood flow), creating heat (increased temp increases metabolic rate) and redness
- increased capillary permeability, capillary leak fluid, leaked protein rich fluid in tissue spaces (pressure, bring clotting since more fluid means more WBC movement) creates pain and swelling (possible temporary impairment of function)
- attract neutrophils, monocytes, lymphocytes
- leukocytes and macrophages secrete pyrogens when exposed to foreign substances
- pyrogens raise body temperature (increase metabolic rate-repair faster and causes liver and spleen to sequester iron and zinc which is needed by microorganism)
what are four properties of adaptive immunity?
what is the difference between active and passive immunity?
- active when individual is exposed to an antigen
- passive when antibodies are transferred from another source
what are antigens?
substances that can mobilize adaptive defenses and provoke an immune response. it is the targets of all adaptive immune responses
how to activate T cells?
antigen binding to inactive CD8 cell
how do cytotoxic T cells kill?
- releases perforins (forms pores) and cytokines (activates apoptosis) by exocytosis
- binds to specific membrane receptors on target cells that trigger apoptosis
- releases lymphotoxins, which disrupts metabolism
roles of T cells?
- stimulate both cell mediated and anti-body mediated immunity
- help activate T and B cells, induce T and B cell proliferation
- release cytokines to recruit other immune cells
- there is no immune response without Helper T cells
describe B cell activation and sensitization
antigens bind to antibody molecules, sensizetized B cell display antigen on Class II MHC receptor, sensitized B cell attaches to helper T cell which activates them with cytokines and B cell differentiate to memory B cells and plasma cells
what is the role of plasma cells?
secrete specific antibodies, which bind to free antigens marked for destruction
what is the role of antigen-antibody complexes?
do not destory antigens; they prepare them for destrution by innate defenses
what is the variable regions at end of each arm called?
antigen binding sites (determine specificity of antibody)
what are portions of antigen antibodies bind to called?
antigenic determinant sites
what are the 5 classes of antibodies based on structure?
- largest and most diverse (75-80% of plasma antibodies)
- responsible for resistance agaisnt viruses, bacteria
- corss placenta for passive immunity for fetus
- largest structure; pentamer
- attack bacteria, activates complement system
- potent agglutinating agent; responsible for cross reactions of blood types
monomer attached to surface of b cells, functions as B cell receptor; aids in sensitization
- monomer or dimer
- found in exocrine secretions like mucus, tears, saliva
- attack antigens before they enter body
- monomer active in some allergies and parasitic infections
- stimulates basophils to release histamine, triggering inflammatory response
what are naive cells?
not been activated by antigen
how does antigen-antibody complex inactivate?
- by neutralization: masks dangerous parts of bacterial exotoxins; viruses)
- agglutination: (cell bound antigens), easier for phagocytosis
- precipitation: soluble antigens, but insoluble antigen-antibody complexes
what does antigen-antibody activates?
complement system which leads to cell lysis and enhances phagocytosis and inflammation (chemotaxis)