Immune System Flashcards
innate immunity
- first line of defense
- inflammatory response
external immunity
- physical/physiological barriers froms first line of defense
- skin mucous membrane in digestive system
- chemical secretions (lysozyme in tears)
- cilia sweap out pathogens in respiratory system
internal immunity
- neutralize any pathogens that enter
- macrophages and neutrophils eat up foreign organisms through phagocytosis
inflammation
occurs when blood vessels dilate making capillaries more permeable to allow more blood cells to go to the area –> which is why sometimes is read
mast cells
type of leukocyte that causes rally signal
* already present waiting for injury
* injury –> mast cells release histamine –> dilate vessels
* increase in blood flow = vessels more permeable to let immune cells into tissue to fight injury
5 sings of inflammation (SLIPR)
- Swelling
- Loss of function
- Increased heat
- Pain
- Redness
Movement of Molecules
- diapedesis: cells move from capillaries to tissues to fight pathogens
- chemotaxis: cells move in response to chemical signals (ex: histones)
5 types of Leukocytes (WBCs)
Never Let Monkeys Eat Bananas
- neutrophils: phagocytosis in innate immmunity, increase in bacterial infections
- lymphocytes: B cells and T cells; natural killer cells
- Macrophages: phagocytosis in innate immunity, increase in fungal or viral infection; act as APC (antigen presenting cells)
- eosinophils: increase in parasitic infections or allergic reactions
- basophils: increase in allergic reactions (can cause histamine release)
from most present to least present
dendritic cell
- mature langerhan cells
- scan tissues for pathogens
- act as APC (antigen presenting cells)
- migrate to lymph nodes with antigen to activate adaptive immunity
APC
- use TRLS (Toll Like Receptors)= common parts on ALL microbes
- recognize these common parts on pathogens and triggers phagocytosis
INFs (Interferons)
- secreted by virally infected cells –> activate dendritic cells
adaptive immunity
- specific response targets specific antigens on pathogens
MHC (major histocompatibility complex)
part of adaptive immunity
- allow immune system to recognize self vs. intruder
- MHC I: on ALL NUCLEATED CELLS, genetically different for each person (can lead to transplant failure/autoimmune disease)
- MHC II: only on APC (dendrites, macrophages, or B cells)
- body can recognize foregin antigens and foreign MHCs
antigen
immunogenic foregin molecule that is targeted
B cell/humoral immunity
adaptive immunity
- B lymphocytes mature in bone marrow, make antibodies
- antibodies circulate in blood and recognize an antigen on surface of foregin partices –> can cause agglutination, deactivation/signal cells to eat foregin substance
Primary Response –> B cell/humoral immunity
when an antibody sees a matchcing antigen, it will cause B lymphoctye to differentiate into plasma cells (make tons of antibodies) and memory B cells (remember foregin antigen for future
secondary response –> B cell/humoral immunity
when the same antigen is seen by the body, memory B cells will start producing antibodies quickly to get rid of it
* memory B cells are key to vaccinations
* useful for foreign organisms
IgM
antibody class
- structure: pentamer
- first type of antibody produced after exposure to antigen
- largest antibody
- binds to antigen –> activates complement system
IgA
antibody class
- structure: dimer
- found mostly in body secretions
- can provide newborn with passive immunity during breastfeeding
- bind externally to pathogens before they enter circulation
IgE
antibody class
- monomer
- produced in allergens
- found on mast cells and basophils, inducing them to release histamine
IgD
antibody class
- monomer
- function is not understood
IgG
antibody class
- monomer
- found mostly in circulation
- can cross the placenta to provide fetus with passive immunity
- opsonizes bacteria and neutralizes bacterial toxins and viruses
T cell/cell-mediated immunity
adaptive immunity
- differentiate from B cells = directly on cells instead of sending out antibodies
- t lymphocytes mature in thymus
T cells must bind to APC in one of 2 ways
adaptive immmunity –> T cell/cell-mediated immunity
- MHC I presentation: T cells become CD8 T cells (cytotoxic T cells) –> specific and require APC to present antigen; directly kills infected cells by poking holes and degrading enzymes
- MHC II presentation: T cells become CD4 T cells (helper T cells) –> release interleukins to increase immune response; help T and B lymphocytes to differentiate
passive immunity
- gained from receiving the antibodies from another organism
examples - IgG is the only antibody that can cross the placenta, fetus can gain immunity from mother
- newborn can gain immunity from breast milk via IgA antibody
- fetus/newborn = immuno-naive without own active immunity
active immunity
- gained from being infected once previously
- vaccination can introduce the antigen/pathogen in deactivated state to stimulate memory B and T cells (artificial immunity)
Blood Types
- blood has A and B surface antigens. If your body sees blood cells w/ an antigen not recognized by body, it’ll kill it
- so people with AB blood type have both antigens, if you put blood into anyone without AB then it’ll be destroyed
- people with O blood type have no antigens, so you can put their blood into anyone
- Rh factor is another type of antigen that can cause problems in pregnancy
