Immunity

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    Imported from Quizlet

    Created by @jbf

    how do blood vessels constrict

    seretonin is secreated which makes smoot muscle contract

    how does a blood clot form

    platelets release a chemical that through a cascade of events turns fibrinogen into fibrin which acts as a mesh forming a clot

    inflammation stage

    localised response to pathogens. Mast cells are activated and they release histomines and cytokines

    what are histomines

    make blood vessels dilate causing localised heat and redness. Increase the permeability of blood vessels so more blood plasma is forced out

    what do the cytokines that are produced by a phagocyte do

    attract white blood cells and phagocytes to the area

    How do fevers help control infection

    Cytokines stimulate the hypothalamus to increase the temperature and stop pathogen reproducing and increasing the specific immune response

    what is odema

    its swelling caused by histomes

    what do mast cells release

    histomines and cytokines

    what is an opsonin

    any chemical bound to the antigen of a pathgoen, enhancing phagocytosis so they are easily recognised. Phagocytes have receptors that bind to common opsonins

    what do phagocytes form part of

    the secondary non-specific immune response

    what are the two types of phagocytes

    neutrophills macrophages

    describe what a neutrophil is

    has a multilobed nucleus and is released very quickly in large numbers during an infection

    where is a neutrophil made

    made and matures in the bone marrow

    describe what a macrophage does

    have a c shaped nucleus. Are much bigger then neutophils and have slower action

    where are macrophages found

    made in the bone marrow and develop in the thymus gland Found in large quantities in the lymph nodes and travel around the blood as monocytes

    how are phagocytes able to pass from the blood into the tissue fluid

    they have a lobed/narrow nucleus and they can change shape to squeeze between cells in capillary walls

    what is the first stage of phagocytosis

    a pathogen produces a chemical that attracts the phagocyte

    what is the second step of phagocytosis

    the phagocyte recognises the non self antigens on pathogen and binds to it (non specific). This can be aided by opsonin's which bind to and tag pathogens

    what is the third step of phagocytosis

    phagocyte engulfs the pathogen and the pathogen is enclosed in a vesicle called a phagosome

    what is the fourth step of phagocytosis

    lysosomes fuse with the phagosome to make a phagolysosome. Lytic enzymes and hydrogen peroxide digest the pathogen

    What is the fifth step of phagocytosis?

    bacteria broken down to amino acids/sugar/glucose and the waste is expelled by exocytosis

    why do macrophages take longer during phagocytosis

    combine the pathogens antigens with MHC and it moves antigens to the cell membrane It forms an antigen presenting cell. Displays MHC class 11

    whats the structure of an antibody

    made of 4 polypeptide chains. 2 Light and 2 heavy. The region where the two heavy strands joined by disulphide bonds is the hinge region. The tips of the light and heavy chains is the variable region. The base of the 2 heavy chains is the constant region.

    what cells make antibodies

    b plasma cells

    whats the rate of response different between the specific and non-specific immune response

    specific immune response is slower and takes up to 14 days but if it meets the same pathogen again its faster because of memory cells

    what is opsonisation

    the antigen-antibody complex acts as an opsonin for phagocytes to do phagocytosis

    what is neutralisation with antibodies

    if the antigen on the surface of the pathogen was a binding site enabling it from entering cells the antibodies prevent it from happening

    what is agglutination

    some antibodies are made by lots of immunoglobuline molecules which can bind to many pathogens clumping them up

    what are anti-toxins

    antibodies that bind to toxins making them harmless

    what is clonal selection

    selection of specific lymphocyte after exposure to a specific antigen

    what is clonal expansion

    proliferation of specific cells with the appropriate antibody for the antigen

    what are B effector cells

    they have different specific shaped receptor and are chosen during clonal selection and then divide to form clones of plasma cells

    what are B plasma cells

    produce antibodies but only live for a few days

    what are B memory cells

    live for a very long time and provide immunological memory

    what are T helper cells

    have CD4 receptors on cell surface membrane which bind to the non-peptide parts of the MHC 11 on APC to stabilise the reaction

    what are interleukins

    a type of cytokine produced by T helper cells to stimulate other T cells B cells and phagocytes

    what are T killer cells

    produce hydrogen peroxide and a chemical called perforin which kills pathogens by making holes in the cell surface membrane

    What are T memory cells?

    live for a long time and provide immunological memory

    how do T killer cells get activated

    Infected body cells incorporate some of the pathogens antigens into their cell surface membranes by MHC class 1

    describe MHC class 1

    always active in all nucleated cells. The proteins used come from within the cell

    describe MHC class 11

    comes from proteins from the environment and can only be expressed by professional Antigen Presenting Cells

    what is natural passive immunity

    immunity that is gained without an immune response. For example breast milk and the placenta. These are short lasting. No memory cells are made

    what is artificial passive immuntiy

    antibodies are injected externally. No memory cells are made

    how does type 1 diabetes work

    the immune system attacks pancreatic cells and stops them from being able to produce insulin

    how does rheumatoid arthritis work

    Immune system attacks membranes in joints Pain, swelling, reduced mobility

    what is artificial active immunity

    Production of one's own antibodies or T cells as a result of vaccination against disease. Long lasting and produces memory cells