Term
| Functions of the immune system |
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Definition
1) Protect the body against foreign pathogens
2) Restore the body to homeostasis |
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Term
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Definition
| A state in which the body undergoes an exaggerated immune response to an antigen |
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Definition
| A condition in which the immune system considers an individual's own body tissues to be foreign |
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Term
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Definition
| Occurs when the immune system or inflammatory responses fail to function normally, resulting in increased susceptibility to pathogenic microorganisms |
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Term
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Definition
Also called natural, native or non-specific immunity
Natural resistance that is present at birth and protects the individual by providing a natural barrier, activating cells that limit and destroy the capacity of foreign substances to enter and spread throughout the body |
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Term
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Definition
Acquired and specific immunity
Develops as an individual is exposed to foreign substances
Slower performing system than innate immunity, yet is more powerful and precise as it selectively targets foreign substances that it identifies |
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Term
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Definition
Two levels of protection
1) First line of defense: skin and mucous membrane
2) Second line of defense: Cells, chemicals and processes that are activated if a foreign substance breaks through first line of defence |
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Term
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Definition
Phagocytes
Neutrophils
Monocytes
Macrophages
Natural killer cells |
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Term
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Definition
Third line of defence
Specific and has memory |
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Term
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Definition
First line of defence against infection and tissue injury
Constant
Broad specificity
Epithelial cells forming anatomical barriers (skin and mucous membranes)
No memory
Toxins from epithelial cells, lysozome, bacterial toxins
Few cytokines |
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Term
| Innate immunity - inflammatory response |
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Definition
Second line of defence; occurs as a result of tissue injury or infection
Immediate response
Broad specificity
Mast cells, granulocytes (neutrophils, eosinophils, basophils), monocytes, macrophages, natural killer cells, platelets, endothelial cells
No memory
Complement, clotting factors, kinins
Many cytokines |
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Term
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Definition
Third line of defence; becomes active when innate immune system signals the cells of adaptive immunity
Delay between exposure to antigen and maximum response
Very specific
T lymphocytes, B lymphocytes, macrophages and dendritic cells
Specific immunological memory by T and B lymphocytes
Antibodies, complement
Many cytokines |
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Term
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Definition
| A state in which the body undergoes an exaggerated immune response to an antigen |
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Term
| Four types of hypersensitivity reactions |
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Definition
Type 1: immunoglobulin E mediated responses
Type II: tissue specific reactions
Type III: immune complex mediated reactions
Type IV: cell mediated reactions |
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Term
| Type I: IgE mediated hypersensitivity reaction |
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Definition
Most common and mediated by IgE and products of tissue mast cells
Occur against environmental antigens
Most potent mediator is histamine which contracts bronchial smooth muscles, increases vascular permeability and causes vasodilation
Clinical manifestations: itching, conjunctivitis, rhinitis, hypotension, GI cramps, asthma |
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Term
| Type II: tissue specific hypersensitivity reactions |
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Definition
Reactions against a specific cell or tissue
Four mechanisms by which reactions affect cells:
1) Cell may be destroyed by IgM or IgG
2) Antibody-antigen complex may be destroyed through phagocytosis by macrophages
3)Antibody of the target cell is recognised by natural killer cells, which release toxic substances to destroy the cell
4) Antibody binds to target cell receptor and alters the function of the cell |
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Term
| Type III: immune complex mediated hypersensitivity reactions |
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Definition
Caused by antigen-antibody complexes that are formed in the circulation and deposited later in vessel walls or other tissues
Antibody binds to soluble antigen that was released into the blood and the complex is then destroyed by tissues
Non organ specific |
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Term
| Type IV: cell mediated hypersensitivity reactions |
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Definition
Mediated by T lymphocytes and do not involve antibodies
Occur through cytotoxic T lymphocytes or cytokine producing helper cells
Cytotoxic T cells attack and destroy cell targets directly
Examples: graft rejection, skin test for tuberculosis and allergic reactions from contact with plants and latex |
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Term
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Definition
| Hypersensitivity to environmental antigens called allergens |
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Term
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Definition
| A potentially life threatening immediate hypersensitivity response caused by exposure of a sensitized individual to a specific antigen |
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Term
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Definition
Activated components can destroy pathogens directly and can activate or collaborate with every other component of the inflammatory response
Involves either a classical pathway, lectin pathway or alternative pathway |
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Term
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Definition
Artificially acquired passive immunity is a short term immunization by the injection of antibodies, such as gamma globulin, that are not produced by the recipient's cells.
Naturally acquired passive immunity occurs during pregnancy in which certain antibodies pass from the mother to the fetus |
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Term
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Definition
Naturally acquired active immunity occurs when the person is exposed to a live pathogen, develops the disease and becomes immune as a result.
Artificially acquired active immunity can be induced by a vaccine - a substance that contains the antigen |
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Term
| Transfer of passive immunity from mother to fetus |
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Definition
Transfer across the placenta involves is an active process that occurs during the first trimester
Fetus can produce IgG in last trimester
Colostrum in breast milk produces colostral antibodies which provide the newborn with passive immunity against gastrointestinal infections
Maternal antibodies that pass the placenta before birth provide passive systemic immunity |
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Term
| Changes in immunity with ageing |
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Definition
Immune function decreases with diminished T cell function and antibody response to antigenic challenge
Circulating antibodies and immune complexes increase
Thymic hormone production drops as does the organs ability to mediate T cell differentiation
Decreased T cell mediated responses to infections and decreased T cell activity |
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Term
| Non steroidal anti inflammatory's (NSAID's) |
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Definition
A group of drugs having antipyretic, analgesic and anti inflammatory effects; they bear no structural similarity to corticosteroids
Main classes
1) Acetic acids: diclofenac, indomethacin, keterolac, sulindac
2) Fentamates: mefenamic acid
3) Propionic acids: ibuprofen, ketoprofen, naproxen, tiaprofenic acid
4) Oxicams: meloxicam, piroxicam
5) Salicylates: aspirin
6) Coxibs: celecoxib, parecoxib |
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Term
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Definition
All have same therapeutic properties: analgesic, antipyretic, anti-inflammatory
Inhibits prostaglandins which accounts for therapeutic effects but also causes renal and GI toxicity |
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Term
| Classes of microorganisms |
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Definition
| Include bacteria, fungi, parasites and viruses |
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Term
| Opportunistic microorganism |
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Definition
| A microorganism causing infection in an individual that would not normally harm a healthy individual |
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Term
| Microorganisms - Bacteria |
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Definition
Prokaryocytes that can be aerobic or anaerobic, motile or non motile
Many different types and only some are destructive to humans |
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Term
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Definition
Much smaller than bacteria and are smallest pathogenic microorganism
Most common cause of illness in humans and include a variety of diseases such as the cold to AIDS |
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Term
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Definition
Relatively large microorganisms with thick walls that grow as either single celled yeasts or multi celled moulds
Cause disease by adapting to the host environment.
Fungi that colonise the skin can digest keratin
Disease caused by fungi is called mycoses. Mycoses can be superficial, deep or opportunistic
Fungi that invade the skin or hair are called dermatophytes
Fungi causing deep infections enter the body through wounds |
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Term
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Definition
Purpose of a vaccine is to induce long lasting protective immune responses under conditions that will not result in disease in a healthy recipient of the vaccine
Primary immune response is short lived |
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Term
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Definition
Natural products of fungi, bacteria and related microorganisms that kill or inhibit the growth of other microorganisms
Act by preventing the function of enzymes or cell structures that are unique to the infecting agent |
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Definition
Developed to treat influenza, HIV, hepatitis and herpesvirus
Majority mimic a section of viral DNA, rendering viral replication inactive |
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Term
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Definition
| Immunoglobulin proteins of the immune system, with the function of destroying a specific antigen |
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Term
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Definition
| A molecule that binds to an antibody and initiates an immune response because of the body's recognition of the molecule as foreign |
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Term
| Red blood cells (erythrocytes) |
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Definition
| Transport oxygen and carbon dioxide |
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Term
| Platelets (cell fragments without nuclei) |
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Definition
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Term
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Definition
60% of WBC's
"Patrol tissues"
Large numbers released during infection
Short lived - die after digesting bacteria
Dead neutrophils make up pus |
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Term
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Definition
Found in organs, not blood
Made in bone marrow as monocytes
Long lived
Initiate imune responses as they display antigens from pathogens to the lymphocytes |
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Term
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Definition
Cells under attack and release histamine
Histamine + chemicals from pathogens mean neutrophils are attracted to site of attack
Pathogens are attached to antibodies and neutrophils have antibody receptors
Endocytosis of neutrophil membrane = phagocytic vacuole
Lysosomes attack to phagocytic vacuole = pathogen digested by proteases |
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Term
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Definition
Produce antibodies
B cells mature in bone marrow then concentrate in lymph nodes and spleen
T cells mature in thymus
B & T cells circulate in blood |
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Term
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Definition
Antibodies embedded in plasma membrane and called antibody receptors
Receptors recognize antigen on the surface of the pathogen, then B cell divides rapidly
Antigens are presented to B cells by macrophages |
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Term
| B Lymphocytes: Memory cells |
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Definition
| Divide rapidly as soon as antigen is reintroduced |
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Term
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Definition
Some act as labels to identify antigens for phagocytes
Some are antitoxins - they block toxins
Some attach to bacterial flagella making them less active and easier for phagocytes to engulf
Some cause agglutination (clumping) so they are less likely to spread |
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Term
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Definition
2 binding sites
Blood, tissue fluid, can cross placenta
Increases macrophage activity, antitoxins, agglutination |
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Term
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Definition
10 binding sites
Blood, tissue fluid
Agglutination |
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Term
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Definition
2 or 4 binding sites
Secretions (saliva, tears, vaginal, prostate)
Stop bacteria adhering to host cells, prevents bacteria from forming colonies on mucous membranes |
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Term
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Definition
2 binding sites
Tissues
Activates mast cells to release histamine, worm response |
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Term
| Why aren't vaccinations always successful? |
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Definition
Antigenic variation caused by mutation
Antigenic drift (small changes)
Antigenic shift - large changes
Defective immune systems
Malnutrition
Antigenic concealment - parasites live inside body cells |
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