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41 Cards in this Set
- Front
- Back
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microbes
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-microscopic organisms
-some microbobes are parasitic (live in &/or replicate or reproduce in a host organism) Ex. bacteria (e.coli), viruses (HIV, SARS, Ebola), Fungi, Protists, worms |
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pathogens
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disease-causing organisms
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What are the 3 major forms of protection against disease in the human body?
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nonspecific external barriers-try to keep pathogens from entering body
nonspecific internal defenses-cells & chemicals that take action against any foreign invader(kill, repel) -immune response-immune cells that attack specific foreign particles "remember" it for the future |
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Nonspecific External Barriers: skin
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surface of skin is dry, dead cells (not nutritious, dry)
-skin cells slough off frequently-constantly removing microbes that may have landed on skin -sweat, oil, and ear wax contain natural antibiotics |
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Nonspecific External Barriers: mucous membranes
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-surround eyes, line digestive, respiratory, and urogenital tracts
-secrete musuc and tears (both contain lysozymes: antibacterial enzymes) *musus traps microbes in mouth and nose -lining of respiratory tract contains cilia-"sweep" the microbes up & out so the debris can be removed by coughing or sneezing/or swallowed & digested |
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Nonspecific External Barriers:
other secretions |
harmless bacteria of digestive tract- they secrete chemicals that kill harmful bacteria and fungi
vaginal secretions(acidic) & vaginal mucus-trap and kill some microbes urine-acidic & inhibits bacterial growth |
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Nonspecific Internal Defenses: Phagocytic cells
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Macrophages and Neutrophils-travel through the blood
-can move through capillary walls -destroy invaders by engulfing and digesting them -macrophages also eat dead & dying cells produced by natural tissue replacement so they don't leak harmful chemicals) |
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Nonspecific Internal Defenses: Natural killer cells
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(WBCs) kills bosy cells that have been infected, or become cancerous
-recognize surface proteins on viuses & abnormal molecules on outside of cancerous cells -secrete enzymes that attack cancerous or infected cells -secrete enzymes that make holes in cell membranes |
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Nonspecific Internal Defenses: inflammatory response
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-local response to bodily injury
-characterized by phagocytosis of foreign invaders & dead tissue by WBCs & natural killer cells -injury site is "walled off" by clotting fluids from the blood -causes: mucus membranes to leak fluids, injured tissue to get red, swollen, warm, pain to guard & protect area while its healing, mast cells to release histamine, release of cytokines, formation of pus |
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histamine
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chemical that relaxes smooth muscles of blood vessels for increased blood flow (more macrophages and neutrophils)
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cytokines
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chemicals released by macrophages to help with inflammatory response
-communicate w/ WBC-come out of capillaries, blood clottin |
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pus
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mixture of dead bacteria, tissue debris, WBCs (dead/alive)
-pus may form if injury was caused by dirty object |
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Nonspecific Internal Defenses: fever
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-increase in body temp.
purposes: slowing the repro. by bacteria (& other microbes), speeds up production of WBCs, increases production of interferon(a cytokine that reduces viral infection) Cause: 1. macrophages release a cytokine called endogenous pyrogens 2. cytokine travels in blood to hypothalamus causes increase in body temp., shivering, lowers iron content in blood because bac. needs FE to repro. |
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Immune Response
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1. recognize the invader
2. attack it 3. remember it, to prevent future infection |
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Immune System
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a "cellular" system that consists of:
lymphocytes-specialized WBCs chemical antibodies lymph nodes, thymus, spleen, blood |
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T cells
B cells |
T cells- originate in bone marrow, but they differentiate & develop in thymus
B cells- come from bone marrow |
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antigen
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-molecule that stimulates the production of an antibody
-usually a protein or polysaccharide -antigens are found on surface of microboes or cancer cells, or incorporated into membrane of virally infected cell, or dissolved in blood |
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anitbody
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-proteins produced by B cells
-combine w/ a specific antigen & mark it for destruction -Y-shaped |
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T cell receptors
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on surface of T cells
-bind to antigen & trigger immune response but they do not directly contribute to destruction *human immune system randomly makes millions of antibodies & T cell receptors they just wait to bind to a possible antigen |
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Major histocompatability complex (MHC)
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a collection of proteins on a human's cells. they are unique for each person
-transplane patients-take immunosuppressant drugs -humans develop an immunity to their own cell surface proteins early in life by killing off out immature immune cells |
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Humoral Immunity (Antibody-Mediated Response)
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- works best on toxins, bacteria, fungi, parasites
- carried out by B cells 1. infection occurs 2. a few B cells (w/ correct antibodies) bind to antigens on the surface of foreign particle/invader) 3. Antibody-antigen binding causes B cells to divide into clones of original B cells-clonal selection 4. Cloned cells differentiate into memory B cells & plasma cells 5. humoral immunity occurs because-circulating antibodies find foreign molecules-to inactivate them-antibodies may cover surface of invader that marks the invader for destruction (eaten by macrophages) - antibodies may bind microbes together in a clump so its easier for macrophages to eat them 6. complement system |
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memory B cells
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WBCs that remain in blood to provide future immunity to same antigen by producing more plasma cells if needed
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plasma cells
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WBCs that produce and secrete antibodies cells make lots of ER, where specific antibody proteins are formed, then released. (Usually only last a few days)
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complement system
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(proteins) bind to stems of antibodies, starting a series of reactions that cause phagocytes to eat or it might form holes in plasma membrane to kill cells
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Cell-mediated immunity
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carried out by T cells
-effective against viral infections helper T cells- help other immune cells (T cells , B cells) recognize and act against antigens cytotoxic T cells- release proteins that break down plasma membrane of infected, transplanted, or cancerous cells only last a few days memory T cells- provide future immunity to the same antigen by producing more cytotoxic T cells when/if same antigen appears |
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antibiotics
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slow the growth and reproduction of bacteria, fungi, protists
-allow cells of the human immune system to out number & attack invading cells/bacteria |
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neuramindidase inhibitors
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anti viral drugs
-block the ability of newly formed virus particles from bursting out of host cell |
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vaccination
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-administration of weakened (attenuated -> sometimes altered part of dead particle) or dead microbes to confer immunity
-may be given orally (in form of liquid (polio)/edible (banana), injected (needle), or administered using a gene gun (spraying fold drops coated w/ DNA) |
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Vaccination Timeline
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1000 A.D.- people exposed themselves to smallpox deliberately India, China, Africa
1796-Edward Jenner inoculated child with pus from cowpox lesions, then smallpox lesions, then smallpox lesions -smallpox has been eradicated globally, but smallpox virus still exist: CDC (Atlanta), Russia -Vaccinations cause a mild immune response to an antigen, fever...producing some memory cells that are going to protect you in the future |
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Influenza vaccine
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new vaccine must made each year because flu viruses are retroviruses (contain RNA), so they can mutate rapidly
-flu virus outbreaks are tracked globally, then 3 strains are identified, combined, and grown in chicken eggs -sometimes human flu viruses mutate greatly, & combine (genetically) w/ bird flu inside pigs so flu virus transfews to human -potential epidemics or pandemics may occur if flu mutates greatly, or combine w/ animal flu viruses -people may die from seconday infections due to weakened immune system |
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allerigies & allergens
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immune response to harmless antigens & harmless antigens that trigger immune response
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Allergic response
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-antigen enters body & gets recognized by B cell
-B cell carries antibody to molecules on antigen's surface, B cells form plasma cells -plasma cells produce "allergy antibodies"-which bind to mast cell -mast cells release histamine causing inflamation, "leaky" capilarries, mucus secretion, sneezing, coughing, watery eyes |
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Anaphylactic shock
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itching, swelling of airways, hives...
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Autoimmune disease
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-disorder that occurs when immune system produces antibodies against the body's own cells
-causes unknown, but possibly due to some foreign invader that hast surfaceantigens similarto those of body itself |
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juvenile-onset diabetes
multiple sclerosis anemia rheumatoid arthritis lupus |
-islet cells of pancreas attacked
-myelin shealth is attacked -RBCs attacked -joint cartilage is attacked |
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Severe combined immune deficiency (SCID)
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few or no immune cells are formed(due to genetic defect), so immune system does not respond to invading particles-common infection can be fatal
(antibodies from mother protect baby for a few months) -gene therapy using bone marrow and viral vectors that are injected back into patient may be helpful |
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Acquired Immune Deficiency Syndrome (AIDS)
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caused by infection w/ HIV 1 or HIV 2 (retroviruses) so they mutate rapidly - difficult to make a vaccine
-the viruses kill helper T cells, therefore they can't differentiate into cytotoxic T cells & memory T cells AIDS=T cell count of 200/ml of blood AIDS patients usually die from opportunistic infections-take advantage when immune system is weak ex. pneumonia, kaposi's sarcoma(skin cancer) |
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cancer
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-uncontrolled cell growth by undifferentiated cells
-natural killer cells & cytotoxic cells usually kill cancer cells because they have slighty different proteins on outside -some cancerous cells do not have surface proteins so they are not attacked by immune cells -some types of cancer can suppress the immune system -some cancer cells reproduce so quickly that immune system cant keep up |
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tumor
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-group of cells w/ uncontrolled growth
benign tumor(polyp)-located in one area malignant tumor-spread to other areas of body-metastasis |
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Treatments for cancer
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surgery-removal of cells(risk of spreading cancerous cells)
radiation-destroys cancerous cells and nearby healthy cells chemotherapy-drugs kill rapidly dividing cells-including healthy cells: hair follicles (hairloss);intestinal lining cells (nausea) |
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experimental treatments, recently developed treatments for cancer
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-cancer vaccines
-stimulation of immune system to attack cancer cells -use of antibodies specifically designed to recognize tumor cells (target)-so the drug or radioactive molecules go only to cancerous cells |
