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24 Cards in this Set
- Front
- Back
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Define pathogen
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an organism or virus that causes a disease
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Why are antibiotics effective against bacteria but not viruses?
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antibiotics block specific metabolic pathways found in bacteria; viruses reproduce using the host cell's metabolic pathways, which are not affected by antibiotics
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Outline the role of the skin in defence against pathogens
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The skin is an external, nonspecific defense against pathogens. It is a physical barrier which, if damaged, must be repaired by blood clotting. It is also a chemical barrier because it produces waxes (making it harder for the pathogen to enter) and sweat (which can injure pathogens).
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Outline the role of the mucous membranes in defence against pathogens
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The skin is an nonspecific defense against pathogens. It is a physical barrier which. It is also a chemical barrier because it produces mucus, which makes it harder for the pathogen to enter.
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What do phagocytic leucocytes do?
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They ingest pathogens in the blood and body tissues by phagocytosis (make sure you know what that is). Once the phagocytic leucocytes/macrophages ingest the pathogen, they break it down using the enzymes in their lysosomes. Antigens are displayed on the surface in an MHC protein; at this point you can call the cell an antigen-presenting cell. It will travel to the lymph node to stimulate helper T cells
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Define antigen
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Substances (molecules) which can stimulate the production of antibodies. Pathogens have many types of antigens on their cell surface (often membrane proteins or carbohydrates). Keep in mind that human cells also have antigens. We recognize our own antigens as "self." If you get a transplant or a blood transfusion from another human with different antigens then your immune system will respond to that new tissue/blood.
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Define antibody
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A Y-shaped protein that recognizes and binds to specific antigens. (Make sure you understand the difference between antigen, antibody, and antibiotic…don't mix them up!)
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Explain antibody production
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IB topic 6: "Many different types of lymphocytes exist. Each type recognizes one specific antigen and responds by dividing to form a clone. This clone then secretes a specific antibody against the antigen." IB topic 11 adds more: Macrophage ingests pathogen and presents antigen on MHC protein. Antigen-presenting cell goes to lyph node and activates helper T cells (only the helper T cells that can help fight the disease are activated; those cells divide rapidly; "clonal selection"). Helper T cells activate B cells (clonal selection). Some of these differentiate into plasma cells, which produce antibodies; others differentiate to become memory cells.
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What do helper T cells do? How are they activated?
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Activate B cells and cytotoxic T cells. Activated by antigen-presenting cells/macrophages/phagocytic leucocytes by clonal selection.
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What do B cells do? How are they activated?
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B cells differentiate into plasma cells and memory cells (see other flashcards). Activated by helper T cells and antigen .
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What do plasma cells do? Where do they come from?
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They secrete antibodies. They are a type of B cell (undifferentiated B cells divide during clonal selection and then differentiate into plasma cells and memory cells)
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What do memory cells do? Where do they come from?
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They allow your body to respond very quickly (lots of antibodies made really fast) the NEXT time you are exposed to the pathogen.. They are a type of B cell (undifferentiated B cells divide during clonal selection and then differentiate into plasma cells and memory cells)
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What do cytotoxic cells do? How are they activated?
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Kill virus-infected cells and cancerous cells. Activated by helper T cells and antigen .
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If you have a bacterial infection, what specific defences let you kill it?
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Antibodies are good against extracellular pathogens and toxins. You want to state this and explain how you produce antibodies (see other flashcards)
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If you have a viral infection, what specific defences let you kill it?
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Cytotoxic T cells are good against intracellular viruses. You want to state this and explain how you produce cytotoxic T cells (see other flashcards)
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What are some internal, non-specific defenses?
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Fever, inflamation, phagocytosis by macrophages
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What is clonal selection and where do you see examples of it in the immune response?
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clonal selection: a small number of lymphocytes are activated and divide rapidly to produce a clone of cells which are all effective against the particular pathogen your body is fighting; Helper T cells (activated by macrophages), B Cells (activated by helper T cells), Cytotoxic T cells (activated by helper T cells)
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What is HIV?
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the virus that causes AIDS (human immunodeficiency virus)
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What is AIDS?
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the disease caused by HIV (Acquired Immunodeficiency Sydrome)
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What is the cause of AIDS?/ How does AIDS effect the immune system?
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Caused by HIV; causes low number of helper T cells; therefore, less B cells are activated and less antibodies are produced; this causes the body to become more vulnerable to pathogens (people with AIDS die from secondary infections or rare cancers that they can't fight off)
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How is AIDS transmitted?
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Transmission involves transfer of body fluids; HIV does not live outside the body; Sexual intercourse (vaginal, anal or oral)(small cuts); Childbirth (through cuts w/blood); Through placenta and in breast milk (lower risk); Needle sharing (traces of blood on needles); Blood transfusion (safe in US); blood products/factor VIII used to treat hemaphiliacs (now considered safe in US)
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What are the social consequences of AIDS?
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Discrimination: Individuals with HIV may become stigmatized and not find housing, partners or employment; Cost of health care to countries/insurance; Families become poorer if the individual with AIDS was the wage earner and does not have/is refused life insurance. Reduction of workforce; Grief of family and friends ; Orphaned children…family structure/stability affected; Sexual activity in a population may be reduced because of the fear of AIDS (affects people of all ages, sexes, genders, sexual orientations, socioeconomic ststuses, etc)
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What sort of drugs are used against bacteria and viruses?
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Antibiotics for bacterial infections; antivirals for viral infections
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Do antibiotics and antiviral drugs give you immunity against a disease?
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no
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