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63 Cards in this Set
- Front
- Back
Where does innate immunity originate? |
Born with it |
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How does innate immunity work? |
Always works the same way against any type of invading agent e.g. virus/red blood cell |
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What is innate immunity? |
Non specific resistance |
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Where does acquired immunity originate? |
Have to be exposed to something for the first time |
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Explain the process of acquired immunity |
After first exposure, body mounts a specific immune response that triggers production of lymphocytes that remember that they have seen it |
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How else do we receive immune response cells? |
Breast feeding |
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What is acquired immunity |
Specific defences Protect against specific pathogens |
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What happens once an organism gets past the innate lines of defence? |
Body has to react to it more specifically |
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What are the 6 types of innate defence/immunity? |
Physical barrier (skin) Normal microbial flora Phagocytosis Immune Surveillance Chemical defences: cytokines, the complement system Inflammation |
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Describe skin |
Keeps hazardous organisms and materials outside body
1. Waterproof 2. Secretions on surface that are antibacterial 3. Maintain pH of skin at neutral 4. Fairly thick 5. Have sweat glands that wash out bacteria by secretions |
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Describe phagocytes |
Engulf pathogens and cell debris |
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What are the 5 types of phagocytes? |
Fixed macrophage: (in tissues) Free macrophage (in tissues) Neutrophil: (circulate in blood, arrive first but don't survive long, puss) Eosinophil (circulate in blood, increased in people with allergies, important in parasitic infection) Monocyte (in blood) |
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Explain the 4 step process of phagocytosis |
1. Recognition: that object is non self/foreign 2. Attachment: attach to surface of phagocyte 3. Ingestion: phagocyte puts its arms around it and brings it into self Destroy: join up with vesicles that contain enzymes (enzymes break down and kill it)
Also clean up cellular debris from tissue injury
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What is immune surveillance? |
Destruction of abnormal cells by NK (natural killer) cells in peripheral tissues |
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What are abnormal cells (re immune surveillance)? |
Infected with viruses of cancers |
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What is the process of immune surveillance ? |
NK cells circulate around lymphatic system and DETECT cells that look like themselves but have something unusual/different about them e.g. cancer cells (have proteins on surface) --> then destroys them |
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What happens to old people re immune surveillance? |
Not working so well so by time does see them too late |
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What are cytokines and what do they do? |
Stimulate haematopoiesis Regulaye lymphocyte growth, activation and differentiation Chemical messengers that coordinate the defences against viral infections
Activate macrophages |
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What is an example of a cytokine? |
Inferferons |
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What will a viral infected cell do? |
Produce cytokines (interferons) |
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Where is the complement system found? |
Circulatory system (blood)
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What does the complement system consist of? |
Circulating plasma proteins that assist antibodies in the destruction of pathogens
Enhanced adherence of foreign antigen to phagocytes (opsonisation) Damage foreign cell membranes --> lysis Cause histamine release from mast cells --> inflammation Attract neutrophils for phagocytosis --> inflammation |
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What state are the circulating proteins (re the complement system) in when circulating around? |
usually inactive |
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What do the circulating proteins re complement system do? |
When exposed to bacterial cell --> triggers massive response bacterial cell destroyed- holes punched through it (lysed pathogen)
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How does the complement system assist the specific immune system? |
Because circulating proteins are helping antibodies |
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What is acute inflammation? |
Local response to any cell death or tissue injury e.g. trauma, infection, radiation |
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What are the 7 features of acute inflammation? |
1. Blood flow increased (local vasodilation: arterioles & pre capillary sphincters) 2. Phagocytes activated 3. Capillary permeability increased 4. Complement activated 5. Clotting reaction walls of region 6. Regional temp increased (will increase activity of enzymes) 7. Adaptive defences activated (important in stimulating specific immune response) |
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What are the cardinal signs of inflammation |
Redness Heat Swelling Pain Loss of function
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What is an antigen? |
Foreign substance that is capable of triggering a specific immune response |
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What is active immunity? |
Develops in response to antigen exposure |
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What is passive immunity? |
produced by transfer of antibodies from another source |
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What is naturally acquired active immunity? |
Develops after exposure to antigens in environment |
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What is artificially induced active immunity |
Develops after administration of an antigen to prevent disease |
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What is naturally acquired passive immunity |
Conferred by transfer of maternal antibodies across placenta or in breast milk |
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What is artificially induced passive immunity |
Conferred by administration of antibodies to combat infection |
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What is normal microbial flora? |
Microbes that are present normally in various sites of the body and protect the body against infection |
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Where are normal microbial flora located? |
Skin Intestine Upper respiratory tract Genital tract |
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What do normal microbial flora do? |
Create secretions that pathogens don't like --> help protect body against infection |
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What is the function of inflammation? |
Localisation of foreign material Neutralisation or destruction of foreign material Removal of foreign material & cellular debris from tissue Preparing the area for repair
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What is temperature for fever? |
>37 |
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What temperature --> life threatening? |
>42 (damage to nerves and enzymes --> failure of body system) |
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What are the possible benefits of fever? |
Increase metabolic rate of phagocytes Increased activity of enzymes Reduced growth of microbes by increasing temp |
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What is an example of labile tissue? |
Skin Gut |
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Labil tissue repair... |
really well |
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What are labile tissues always doing |
Regenerating (often get abraded) |
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What happens if large area of labile tissue damaged? e.g. large burn |
Will form scar tissue because it is too big for repairing cells from edges to repair whole thing |
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Will stable tissue regenerate? |
if necessary e.g. liver |
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Can permanent tissues regenerate? |
No e.g. cardiac tissue --> scar tissue |
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What are the 3 other factors affecting tissue regeneration |
Blood supply: pimple on face vs leg Age of person Extent of damage |
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What are the non beneficial effects of acute inflammation? |
Short term loss of function Fibrous scarring off tissue --> permanent loss of function Pain Can cause further tissue damage --> more inflammation --> chronic inflammation |
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What is chronic inflammation? |
Inflammation for prolonged duration |
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What could chronic inflammation follow? |
Unresolved acute inflammation |
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What may chronic inflammation develop as a response to? |
persistent infection e.g. Hep B, TB Exposure to inert particulate aterial e.g. asbestos Prolonged exposure to midly toxic substances e.g. cement dust or silicone dust Some autoimmune diseases e.g. rheumatoid arthritis |
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What does chronic inflammation eventually result in? |
Widespread fibrosis (scarring) of the lungs |
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What is the connection between degree of exposure and degree of fibrosis |
Direct correlation |
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Fibrosis may progress... |
in the absence of further exposure |
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What does acquired immune system depend on? |
Activity of lymphocytes |
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What does acquired immune system protect against |
specific pathogens |
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list some physical barriers |
Outer layer of skin Hair Epithelial linings of internal passageways Secretions that flush away materials Sweat glands, mucus and urine Secretions that kill or inhibit microorganisms Enzymes Antibodies Stomach acid |
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What ways do activated macrophages respond to pathogens |
Engulf pathogen and destroy it Bind to pathogen so other cells can destroy it Destroy pathogen by releasing toxic chemicals into interstitial fluid |
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What is immunological escape? |
Some cancer cells avoid NK cells |
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How do virus infected cells present? |
Present abnormal proteins on their membranes which allow NK cells to identify and destroy them |
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What is the resolution of acute inflammation? |
Removal of foreign material and cell debris by phagocytes Exit of phagocytes Reabsorption of fluid Replacement of lost tissue/ regeneration of functional tissue or replacement with scar tissue |