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Acquiring immunity
Karten in diesem Stapel (45)
- 1What are the four non-specific defence mechanismsUnbroken skin
Acids in body
Epithelium in respiratory tract
tears - 2What is special about non-specific defence mechanismsThey work the same way every time regardless of the pathogen or whether its the first or second attack
- 3How does each non-specific defence mechanism workUnbroken skin is unpenetrable by pathogens & if broken blood clotting forms a barrier
Hydrochloric acid in the stomach and the acidic pH in the vagina denatures pathogens enzymes
Epithelial cells are covered in mucus and cilia. Mucus traps pathogens and the cilia beat to move the mucus to the back of the throat where it can be swallowed.
Conjunctiva is protected by fluid secreted by tear ducts. It contains lysozymes which digest bacterial cell walls. - 4If a pathogen enters the body what is the second line of defence >Phagocytosis and inflammation
- 5What leucocytes is phagocytosis carried out byNuetrophils and monocytes/macrophages
- 6what is phagocytosisis a form of endocytosis. A process by which a phagocyte engulfs a particle/ pathogen to form an internal vesicle known as a phagosome
- 7Outline the mechanism of phagocytosisCells damaged by pathogens release cytokines to attract phagocytes
The Bacteria are coated in plasma protein- opsonins
Phagocytes recognise the bacteria
Phagocyte engulfs the bacteria
Bacteria becomes enclosed in a membrane coated vesicle called a phagosome
Lysosomes containing digestive enzymes lysins fuse to phagosome
Lysins break down the bacterium
Soluble product diffuse into cytoplasm - 8what are opsoninsEnhance phagocytosis by marking the antigen marker on the pathogen
- 9What are lysosomesmembrane bound organelle found in cells that contain hydrolytic enzymes (enzymes that break chemical bonds by the addition of water)
- 10How are pathogens engulfed by phagocytesThe pathogen covered in antibodies and opsonins attaches to the phagocytes surface receptors. The pathogen is engulfed by the infolding of the phagocyte membrane
- 11What causes inflammationHistamine is released by damaged cells
- 12What does histamine doIt causes vasodilation of capillaries.
- 13What does the vasodilation causeMore blood flows to the damaged tissue. Temperature of the wound rises. Which increases ROR and slows the rate of bacterial growth.
When capillaries dilate they become more permeable and leak plasma- plasma contains neutrophils, monocytes and proteins - 14What is special about the immune responseThe cells involved in the immune response can attack the pathogen without causing harm to the bodies tissues
- 15How do the cells in the immune response know how to distinguish between pathogens and body cellsThey use antigen markers on cells to distinguish between pathogens and body cells
- 16What are antigensMacromolecules such as glycoproteins. Found on the surface of cells.
- 17What are antibodiesProteins. Used to identify and neutralise pathogens.
- 18What cell produces antibodiesB lymphocytes
- 19Describe the structure of an antibody4 polypeptide chains
2 long chains and 2 short
2 binding sites ( variable region) - 20What do the binding sites doFit exactly on antigen markers on pathogens. Antigens are complementary shapes. Each antibody has a binding site specific for only one antigen
- 21What are the five ways in which antibodies workAgglutination
Precipitation
Neutralisation
Lysis
Opsonins - 22What is agglutinationAntibodies bind to bacterial antigens and cause the bacteria to clump together. This makes it easier for phagocytes to engulf them
- 23What is precipitationAntibodies cause soluble antigens to precipitate out so they can be engulfed
- 24What is NeutralisationAntibodies bind to toxins produced by foreign cells so they do not cause harm
- 25What is lysisAntibodies bind to foreign cells and attract enzymes that attach to the antibodies and digest the foreign cell
- 26What is opsoninsThe constant region on the antibodies binds to the pathogens antigen. It effectively holds the pathogen on the phagocyte so it can be engulfed
- 27Where are B lymphocytes formed and maturedB lymphocytes are formed by stem cells in the bone marrow. They also mature in bone marrow
- 28What is unique about B lymphocytesEach B lymphocytes is capable of producing a different antibody. Each B lymphocyte has an individual receptor on its plasma membrane that is complimentary to one pathogen
- 29What are plasma cellsleucocytes capable of producing large quantities of antibodies. The are differentiated from B lymphocytes
- 30What is a pathogena disease causing organism
- 31How do B lymphocytes work in the Primary immune responsePathogen enters body.
One B lymphocyte will have the receptors that are complementary to antigens on pathogen.
B lymphocytes divide by mitosis
These clones differentiate into plasma cells
Plasma cells secrete specific antibodies against the pathogen. - 32How do B lymphocytes work in the secondary immune responseSome of the B lymphocyte clones form Memory B Lymphocytes
Memory cells do not secrete antibodies but act as an immunological memory of the pathogens antigen.
When the antigen is encountered again the memory cells divide rapidly to produce plasma membranes - 33Where are T lymphocytes produced and maturedProduced by stem cells in bone marrow but mature in the thymus gland
- 34What is special about T LymphocytesEach lymphocytes has different shaped receptors on their plasma membrane.
They work with macrophages - 35What do T lymphocytes differentiate intoT killer lymphocytes
T helper lymphocytes
T suppressor cells - 36How do do the T lymphocytes work with macrophagesVirus invades body and is recognised by macrophages outside body cells
Pathogen engulfed by phagocytosis
Macrophage digest pathogen and presents it antigens on its plasma membrane
Body cells also present pathogens antigens on plasma membrane
T lymphocyte with complementary receptor binds to the antigen on the macrophage and is stimulated to undergo mitosis
T lymphocyte forms clones
Clones differentiate into T killer cells which kill any cell with the specific antigen and T helper cells that secrete cytokines
Cytokines stimulate phagocytosis and antibody production by B lympohcytes
Cytokines also induce T killer cells to divide by mitosis - 37How do T killer lymphocytes workT killer lymphocytes attach to the body cells presenting the viral antigen
T killer cell produces perforins to make holes in the cell membrane
Cell is destroyed - 38What do T suppressor cells dostop the immunological response
- 39What causes the delay when a pathogen first enters the bodyThe delay is caused by the body trying to kind the right T lymphocyte with a complementary receptor. The T lymphocyte has to then divide and produce T helper cells to produce cytokines to stimulate B lymphocytes. The B lymphocytes then have to divide into plasma cells
- 40What three types of vaccination are thereLive vaccination - contain living organisms. Pathogen has been sub-cultured so they do not cause disease.
Dead microorganism - Killed by heat or chemicals but still carries antigens
Pathogen fragment viral component can be used. EG a viral coated protein - 41What is herd immunityPrinciple that if the majority of the population are vaccinated the pathogen population is reduced as the pathogen can not be transmitted. Thus protecting the most vulnerable in society
- 422 HIV testsPolymerase chain reaction
HIV antibody test - 43How does the polymerase chain reaction detect HIVExtract DNA from leucocytes in a blood sample. HIV inserts a copy of genetic material into T helper lymphocytes
DNA amplified
Proviral DNA is compared to section of Beta Haemoglobin gene
If both the proviral and Beta Haemoglobin DNA is found the person is HIV positive - 44How does the HIV antibody test workPEople who have HIV have HIV antibodies present in blood.
Test dish has HIV antigen markers on.
If the blood contain HIV antibodies they will attach to the antigen markers. Dish is washed and a second antibody is added.
The antibody has an enzyme attached and if the HIV antibody is there it binds to it. When the antibody and HIv antibody bond a dye is released - 45What is a mantoux testSmall amount of serum containing TB antigens is injected under skin. If the person is immune to TB they will produce n immune response- inflammation
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- Karteikarten am Acquiring immunity , erstellt von Jessica Scivier am 03/06/2015.
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