what is the difference between innate and acquired immunity?
innate = is a NON-SPECIFIC wide range of general body responses used to ward of pathogens and their toxins
acquired = where specific immune cells (lymphocytes) are activated to ward off a particular pathogen pr substance... part pf the lymphatic system
lack of resistance is called what? and occurs when?
susceptibility... opportunistic organisms that are non-pathogenic
what are four examples of innate mechanisms? (first and second line defense)
what are examples of acquired mechanisms? (third line defense)
placental transfer (passive)
recovery from disease (active)
administration of antitoxin (passive)
give fove characteristics of nonspecific innate immunity...
prevents entry of microbes OR destroys them upon entry prior to onset of disease.
doesn't rely on recognition od specific material
doesn't become more efficient upon exposure to the same organism..
preseint from birth
includes a forst and second line defense
first line ofe defense via skin and mucous membranes includes three types of protection... what are they?
prevention of stasis
explain the mechanical protection
skin =. shedding of skin cells
mucous membranes = mucous traps while cilia move microbes to throat
tears, saliva, and urine wash microbes away
explain the chemical protection...
sebum's acidity prevents growth of bacteria and fungus
lysozymes in sweat break jdown bacterial cells
acidity in gastricjuive and vagina destroy bacterail cells
describe the mechanism of preventing stasis in the body.... basically what mechanism allow this to happen?
flow of urine
upward movement of secretions in bronchial tree.
give the three groups of second line internal defenses...
internal microbial proteins (interferons,complement proteins, transferrins)
fever, inflammation (cytokines,PG's)
innate cells ( phagocytic cells and natural killer cells)
describe complement proteins and the two parhways seeni with them..
group of 20 proteins present in blood plasma and on cell membranes that make up the compliment system which enhance immune, allergic, and inflammatory reactions.
classical: activated by antigen and antibody complexes. final lytic product is a result of cleavages and recombinations of cleavage products.
alternative: stimulated non-immunologically(w/o antibodies). uses the cleavage steps as s
well but bypassesseveral of the steps.
describe the function of interferon proteins (IFN's)
released by virally infected cells to other non-infected cells giving these cells the ability to inhibit replication.
also activate phagocytic cells and natural killer cells, and inhibit cell growth and tumor formation
explain cytokines' role in inflammation
secreted by lymphocytes, monocytes, and natural killer cells. act as effector molecules for many cell types.
describe the cells of thoe immune system
includes phagocytes and lymphocytes (B, T, NK )
identified by their glycoprotiens indicating type and stage of differentiation.
originate from stem cells in bone marrow
continue dofferentiation in the bone marrow and peripherally in lymph nodes, follicles, and spleen
describe what phagocytes are...
derivatives of monocytes that include macrophages and neutrophils.
secrete cytokines, acid hydrolases, proteases, and prostaglandins
process and present antigen to CD4+ T cells
participate in delayed hypersensitivity reactions
may be directly capable of killing tumor cells
what are the two types of macrophages seen in the body?
fixed macrophages = stand guard in specific tissues
histiocytes = skin
kupffer cells = liver
alveolar = lungs
microglia = brain
spleen, red marrow, lymph nodes
wandering macrophages = found in most tissue
what are antigen presenting cells? what are the 3 types?
engulf antigens, then present fragments to T cells.
1. dendritic = CT and epidermis (langerhan's cell)
2. Macrophages = CT and lymphoid organs
3. B cells
how do NK cells work and where are they found?
attack cells lacking MHC antigens or self cell surgace receptors... also kill tumor, fungi, and cells altered by viral infection (perforin is involved in this type of killing)... can also lyse cells be antibody-dependent cell-cytotoxicity
these LYMPHOCYTES are found in the blood, spleen, lymph nodes, and red bone marrow
how does specific acquired immunity (humoral = B cells, cellular = T cells) differ from innate immunity?
distinguis self from foreigness
describe B cells
identified by glycoproteins for type and stage
originate in bone marrow from B lymphocytes
continue to dofferentiate in marrow and periphery where theycluster in centers of lymph nodes and follicles in spleen.
15% of circulating lymphocytes
describe T cells
originate in bone marrow and differentiate in thymus where they produce cytokines
populate in oaracortical and deep medullary areas of lumph nodes and periarteriolar sheaths of spleen
70% of circulating lymphocytes: two classes based on surface markers:
what is a normal ratio of the two types of T cells?
any other ratio indicates problems such as AIDS (0.5:1)
what are the three types of T cells and their function?
1. Helper AKA T4, Th cells: recognize antigens with MHC-II molecules... secrete cytokines such as interleukin-2 (costimulator of Th, Tc, and B cells)
2. Cytotoxic AKA T8, Tc cells: recognize antigens associated with MHC-I molecules
3. memory T cells: recognize original invading antigen to allow for swifter responses for future invasions.
describe primary response...
exposure to immunogen triggers induction phase, where one of two things happen:
1. humoral immunity: refers to destruction of antigens by antibodies. mainly works against EXTRACELLULAR pathogens of body fluids... B cells express specific immunoglobin on surface --> when immunoglobin reacts interacts with specific antigen, B cell proliferates and differentiates in to plasma cell--> plasma cells secretes large quantities of Ig
2. cell mediated immunity = destruction of antigens by T cells... good against INTRACELLULAR pathogens.
describe secondary response...
second exposure induces T cells to release cytokines --> class swithching occurs in T cells... this occurs due to memory B cells.
give the differences in onset, magnitude, life, and Ig's of primary and secondary response.
slow onset, low mag, short lived, IgM
fast, high mag, long lived, IgG or IgA or IgE
as an overview what are 4 charactersitics of the immune system?