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15 Cards in this Set
- Front
- Back
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What is immunity? |
Ability of organisms to resist infection by protecting against disease-causing microorganisms that invade their bodies |
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What is an antigen? |
Any part of an organism or substance that is recognised as non-self/foreign by immune system and stimulates an immune response |
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What does the presence of an antigen trigger? |
Production of an antibody |
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What type of response is a lymphocyte? |
Specific immune response |
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What are the two types of lymphocytes? |
B cells T cells |
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What type of immunity are B cells associated with? |
Humoral immunity- Involving antibodies that are present in body fluids |
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What type of immunity are T cells associated with? |
Cell-mediated immunity- Involving body cells |
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How are both types of lymphocyte formed? |
From stem cells found in the bone marrow |
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Where do B cells mature? |
Bone marrow |
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Where do T cells mature? |
Thymus gland |
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What type of disease do B cells respond to? |
Bacteria and viruses, foreign material outside body cells |
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What type of disease do T cells respond to? |
Own cells altered by viruses or cancer Respond to transplant tissues |
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How can T cells distinguish invader cells from normal cells? |
1. Phagocytes that have engulfed and broken down a pathogen present some of the pathogen's antigen's on their own cell-surface membrane 2. Body cells invaded by virus present some of viral antigens on their own cell-surface membrane as a sign of distress 3. Cancer cells present antigens on cell-surface membrane |
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What is the response T cells have to infection? |
1. Pathogens invade body cells or engulfed by phagocyte 2. Phagocyte places antigens from pathogen on its cell-surface membrane 3. Receptors on certain T helper cells fit exactly onto these antigens 4. Activates other T cells to divide rapidly by mitosis and form clones 5. Cloned T cells: -Develop into memory cells that enable rapid response to future infections by same pathogen - Stimulates phagocytosis (engulfing of pathogens) - Stimulate B cell division -Kill infected cells |
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How do killer T cells kill infected cells? |
Produce protein perforin which puncture holes in the cell-surface membrane These holes mean the cell becomes freely permeable to all substances and dies as a result |
