unit two immune system Flashcards
the immune system
provides resistance to disease
what are the two intrinsic systems of the immune system?
- innate (non specific)- 1st and 2nd line of defense
2. adaptive (specific)- 3rd line of defense (memory)
first line of defense
- skin and mucous membrane (physical barrier
- secretions
what are the 5 skin and mucous membranes that destroy organisms?
- acid mantle
- enzymes
- mucin
- defenses
- other chemicals
what modifications does respiratory system have?
cilia
what is included in 2nd line of defense?
- phagocytes; neutrophils and macrophages
- natural killer cells
- inflammatory response cells
- antimicrobial proteins
- fever
phagocytes
digest foreign invaders, WBC’s
what is the process of phagocytes?
- recognize and adhere to non self antigen
- engulf particle making phagosome (new membrane)
- phagosome fuse with lysosome to make phagolysosome
- lysosomal enzyme digest particles
- waste is exocytosed
macrophages
- cheif phagocytic cells
- free and fixed macrophages
neutrophils
- most abundant
- hold the line for others to come but die fighting
natural killer cells
nonphagocytic, large granular lymphocytes
- apoptosis ( cell suicide)
- cancer cells and virus infected cells
- tell cell to die
four cardinal signs of inflammation
- redness
- heat
- swelling
- pain
benefits of inflammation
- dosent spread
- disposes debris and pathogens
- alerts immune system
- repair
stages of inflammation
- chemical release (histamine)
- vasodilation and permeability
- phagocyte mobilization
inflammatory chemical release
- ECF
- release of cytokines (cell movement)
what are other inflammatory mediators?
- kinis
- prostaglandina
- complement proteins
vasodilations and increased permeability
- hyperemia; increase blood flow
- exudate; fluid and clotting
- edema; increased volume of ECF
what are other causes of pain
release of toxins from bacteria
steps for phagocyte mobilization
- leukocytosis: release of neutrophils
- Margination: CAM’s grab into neutrophils
- Diapedesis: flatten and squeeze between endothelial cells
- chemotaxis: positive, neutrophils move towards injury
pus
yellow mixture of dead neutrophils and cell tissues
abscess
lots of puss surrounded by collagen fibers, surgically drained
what two ways do antimicrobial proteins innate defense by?
- direct attack (soldiers)
2. indirect attack (generals)
what are the most important antimicrobial proteins?
- interferons
- complement proteins
interferons
-warn healthy neighboring cells about the bacteria or virus
what are the two types of interferons
- A and b; activate NK cells
2. y (gamma); macrophages and lymphocytes
complement system
circulate blood in inactive form, enhance inflammation and directly destroy bacteria
what are the three pathways of compliment proteins?
- classical pathway
- lectin pathway
- alternative pathway
classical pathway
- adaptive, kills foreign substances
- antibodies
- complement fixation; fix antibody to antigen
lectin pathway
-specific sugars, lectin
Alternative pathway
Spontaneously bind to foreign invader
how is fever signaled
foreign substances secrete pyrogens that tell hypothalamus to increase temp
benefits of moderate fever
- live and spleen to hold onto zinc, so foreign things cant live
- increases metabolic rate
adaptive immune system
specific system that eliminates pathogens or abnormal cells
what does adaptive immune system do?
- amplifies inflammatory response
- activates complement
what is the shortcoming of adaptive immune system?
must have initial exposure before knowing how to defend itself
characteristics of adaptive immunity
- specific
- systemic
- memory
what are the two branches of adaptive system?
- humoral immunity
2. cellular immunity
humoral immunity
antibodes circulate freely
bind to target cell to inactivate and mark for destruction
not directly killing
cellular immunity
- directly killing
- enhance inflammatory response
- T cytotoxic cells
antigens
the targets
characteristics of antigens
- complete antigen or hapten (half)
- contain antigenic determinants; what antibodies look for
- can be self antigen
important properties of complete antigens
- immunogenicity- produce lymphocytes to multiply
2. reactivity- reactor bind with antibody
antigenic determinants
part of antigen that antibodies bind to
characteristics of antigenic determinants
- . mobilize lymphocytes
- form antibodies against them
self antigens
not antigenic to self but antigenic to others
MHC proteins
T lymphocytes recognize only antigens that are presented on MHc proteins ( the little flag pole
adaptive immune system cell types
- B lymphocytes- humoral, antibodies
- t lymphocytes- cellular, cytotoxic
- antigen presenting cells- no specific antigens, role in immunity
lymphocyte Development, maturation and activation
T and B lymphocytes bind to only what they are looking for
5 steps of lymphocytes
- origin; bone marrow and thymus
- maturation: go to primary lymph. organs to be tested in pos. and neg. selection. to see MHC and to not see themselves
- seeding secondary lymphoid organs: naive, pass test but not seen action
- antigen encounter and activation: triggers lymphocyte to develop further. Clonal selection, binding to specific antigen
- proliferation and differentiation; lymphocyte proliferates. effector cells fight, some are memory cells
major types of antigen presenting cells
- dendritic cells
- macropgahes
- B cells
dendritic cells
- helper T cells in lymph node
- most effective
- immunity
macrophages
- present antigens to T cells
- activate and become more hungry
B cells in APC’s
- present to helper T cells before activation
- own activation
primary immune response
- cell proliferation and differentiation upon exposure
- 3 to 6 days of lag period
- plasma antibody in 10 days
secondary immune response
- reexposure to same antigen, gives faster, more prolonged and effective response
- memory
- respond within hours
active humoral immunity
when B cells encounter antigens and produce specific antibodies
passive humoral immunity
when ready-made antibodies are introduced into body
naturally acquired
formed in response to actual bacteria or virus
artificially acquired
vaccine
variable regions
at end of each arm, antigen binding sites
constant regions
stems, common function
antibodies
immunoglobulins, bind to specific antigen detects by B cells
do not destroy, they inactivate them and tag them
what are the five c lasses of ig
- igM; first released
- igA; mucous
- igD; B cells
- igG; most abundant, 75-85%
- igE; allergies
what are the 4 defense mechanisms antibodies use?
- neutralization- blocking
- agglutination- clumping
- precipitation- fall out
- lysis- splits
CD4 cels
- naive
- Helper T cells
- regulatory T cells
CD8 cells
cytotoxic T cells
what are the two classes of MHC proteins
- class I MHC- all but RBC’s
2. class II MHC- only antigen presenting cells
class I MHC proteins
- endogenous antigen
- self or non self antigen
- only CD8 cytotoxic cells can bind
class II MHC proteins
- exogenous antigens
- only CD4 helper T cells can bind
helper T cells
- humoral and cellular arms
- activate and proliferate B and T cells
- secerte cytokines to recruit immune cells
- without Th, there is no immune response
activation of B cells
- T cell dependent antigens
2. T cell independent antigens- weak
activation of CD8 cells
- helper T is required
- cause dendritic to express co-stimulatory molecules
cytotoxic T cells
- directly kill other cells
- lethal hit by releasing performs and granzymes to stimulate apoptosis
what do activated Tc cells target?
- viral cells
- bacteria
- cancer
regulatory T cells
- preventing autoimmune reactions
- supress self-reactive lymphocytes
- allograft; transplant from other person
Immunodeficiency
congenital or acquired conditions that impair functions or products of immune cells
autoimmune disease
when immune system loses ability to distinguish self from foreign
