Immune System Flashcards
Pathogens
disease-causing agents
two lines of defense against pathogens
specific and nonspecific
Specific defenses
response against a very specific target; carried out by lymphocytes that recognize SPECIFIC invader (most common type of defense)
Nonspecific defenses
NOT the immune system! guard against anything foreign/pathogenic
Only place in body that make antibodies
B cell lymphocytes
mechanical barriers
prevent entry of certain pathogens
2 ex od mechanical barriers
unbroken skin and mucous membranes
Chemical barriers- 6 examples
pH, interferons, fever, natural killer cells (lymphocytes), inflammation, phagocytosis
How is pH a chemical barrier
Highly acidic stomach kills many pathogens
interferons
(non specific defense) hormone-like peptides (amino acids) that serve as anti-viral substances
what produces interferons
virus infected cells
what do interferons interfere with
viral transcription
Do interferons usually kill the virus
NO usually lose but warns surrounding cells to produce anti-viral enzymes before virus gets to them
self limiting
it will eventually stop
what does DNA code for
proteins
Immunocompromised
immune system is not working correctly
Fever
(non-specific defense) interferes with bacterial growth condition bc limits amount of iron in blood by increasing temp, thus fewer available nutrients for bacteria
What does a fever do to phagocytic cells
They attack with greater vigor when the temperature rises
Natural killer cells (lymphocytes)
(Non-specific defense) recognize and destroy abnormal (cancer&virus) cells when they appear; release perforins which cause cell membrane to disintegrate destroying the infected cell
Perforins
put holes (perforate) in cells membrane to kill abnormal cell
Inflammation
(non-specific) tissue response to pathogen; redness, swelling, heat, and pain
What causes swelling in inflammation
histamine causes capillaries to release WBC through diapedesis and those wet WBC go to area to fight infection, but bring fluid with them since they were in capillaries and are wet
fibroblasts and inflammation
increase fibrin, sac production, active phagocytosis, cell replacement
How is inflammation a helpful defense against pathogens?
When you contain something in one area it can’t spread, and its all in one place so its easier to attack
hernia
broken out
Most active phagocytes
neutrophiles and monocytes (macrophages once leave the blood)
Phagocytosis
(non-specific) phagocytes leave blood and go to area of infection; also removes foreign particles from the lymph
What 3 cells does lymphatic tissue ALWAYS have
B cells, T cells, and macrophages
Immunity
(immune system-specific response) the response mounted by the body against a SPECIFIC recognized foreign antigen (non-self molecule)
Antigens (agglutinations)
inventory of “self” proteins, polysaccharides, glycoproteins/glycolipids made before birth that promote immune response
How are antigens made
thymocytes–> thymus gland–> become T cell lymphocytes (recognize self)
Haptens
small molecules that combine with large molecules to become antigenic (capable of eliciting immune response)
Out of the lymphocytes that red marrow releases in fetal development, which become T/B cells
MAJORITY become T0cells (70-80%) remainder become B cells
Where do B cells mature
bone marrow
where do undifferentiated lymphocytes go
the thymus and become T cells
Where are both T and B cells found?
In lymphatic organs (ex- lymph nodes)
How/what do T cells attack
(specific defense) attack foreign, antigen-bearing cells (macrophages that ate virus for ex), by direct cell-to-cell contact, providing cell-mediated immunity (was activated)
Cytokines (lymphokines)
(specific) secreted by T cells; enhance cellular response to antigens
3 ways besides cytokines, that t cells attack antigen-bearing cells
secrete toxins to kill target cells, growth-inhibiting factors, make interferon to interfere with virus and tumor cells
What does T cell activation require
The presence of an antigen-bearing cell (macrophage or B cell) that had already encountered the antigen
3 types of T cells
memory, helper, and cytotoxic
What is the target of AIDS? What does it attack?
T cells bearing the antigen CD4
Helper T cells
Activation by encountering macrophage that encountered and is displaying antigen. IF the antigen fits the helper T cell’s receptor, it becomes activated!
What do activated T cells release?
cytokines that activate B cells that have already encountered an antigen and cause them to proliferate
Memory T Cells
provide no delay response to any future exposure to the SAME antigen; it remembers how the helper T cell fought it off the first time
Cytotoxic T cells
monitor body’s own cells eliminating virus and tumor infected cells by releasing perforin and other means
How do B cells attack pathogens
by differentiating into PLASMA cells that secrete antibodies; only a small number will become memory cells
another name for antibodies
immunoglobulins
How do body fluids help against pathogens?
They aid in attacking and destroying specific antigens or antigen bearing cells by ANTIBODY mediated immunity
What do plasma cells do
make antibodies
What happens when an active helper t cell comes in contact with a B cell that has encountered an antigen?
The activated helper t cell releases cytokines that activate the B cell and cause it to divide (polyclonal response)
anamnestic response
(secondary response) body recognizes antigen second time and produces antibodies against it
What happens to the B cell once its activated and starts dividing
MOST become become plasma cells some become memory B cells waiting for an attack from the same antigen in the future
antibodies of the plasma are known as…
gamma globulin fractions of plasma
What are the 4 parts each immunoglobulin composed of
2 light chains and 2 heavy chains of amino acids
What is at the end of each chain on an immunoglobulin?
variable regions as the ends that serve as unique binding sites; this is what makes one antibody different from another
are antibodies/immunoglobulins specific?
Highly specific
five different antibody isotopes
IgA, IgD, IgE, IgG, IgM
IgA
mucosal areas: gut, respiratory tract, urogenital tract; prevents colonization by pathogens. also found in saliva, tears, and breast milk
IgD
antigen receptor on B cells that have not been exposed to antigens. Activates basophils and mast cells to produce ANTIMICROBIAL FACTORS
IgE
binds to allergens and triggers histamine (inflammation) release from mast cells and basophils and is involved in allergy. protects against worms
IgG
In its four forms, provides the majority of antibody-based immunity against invading pathogens. **the only antibody capable of crossing the placenta to give passive immunity to fetus
IgM
surface of B cells and in secreted form with high avidity. eliminates pathogens in the EARLY STAGES of B cell mediated immunity before there is sufficient IgG
Humoral actions
Antibody reaction
in what 2 ways do antibodies react to antigens
direct attack & activation of complement
Direct attack by antibody
agglutination, precipitation (falls out of solution), and neutralization of antigens
activation of complement by antibodies
produce opsonization (make phagocytosis easier), chemotaxis, inflammation, or lysis in target cells or antigens
complement =
group of proteins
Primary immune response
when T and B cells become activated for the first time after which some become memory cells
Secondary immune response (Anamnestic response)
if attacked again by same antigen, more memory cells=more rapid response; this ability is LONG LASTING
virulent
strong
attenuated
weak
allergic reactions (hypersensitivity)
excessive immune responses that may lead to tissue damage
delayed reaction allergy
results from repeated exposure to substances that cause inflammatory reactions on the skin (ex: poison ivy)
Immune complex allergic reactions
involve autoimmunity
What do mast cells do during allergic reaction
release serotonin and histamine
anaphylactic shock
when allergy mediators (histamine/serotonin) flood the body; severe form of an allergic reaction
What does histamine do
increase permeability of capillaries
cyclosporin
most famous immunosuppressant but has a lot of side effects
Kaposi’s sarcoma
cancer of the connective tissue
Graves disease
antibodies against thyroid gland antigens causes overactivity resulting in relentlessness, weight loss, irritability, increased heart rate/BP
Juvenile diabetes (type I insulin dependent)
antibodies against pancreatic beta cells; causes thirst, hunger, weakness
pernicious anemia
antibodies against binding site for vitamin B on cells lining the stomach; causes fatigue and weakness
rheumatoid arthritis
antibodies against cells lining joints; causes joint pain and deformity
systemic lupus erythematosus
antibodies against DNA, neurons, blood cells; causes red rash on face, prolonged fever, weakness, kidney damage
