Immunity

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  • Created by: ElishaG
  • Created on: 05-04-17 20:00
What is an immune response?
A response to an antigen that involves lymphocytes and the production of antibodies.
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What are the 5 stages in the defence against pathogens summary.?
1)Primary Defence- External barriers.2)Secondary Defence- Non-specific immune response.3)Secondary Defence- Specific immune response.4)Pathogen destroyed immune to specific antigen.5)Re-infection by antigen, memory cells= faster secondary response.
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What is primary defence?
The prevention of pathogens from entering the body/blood.
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What are examples of primary defence in the eyes/nose/mouth?
1)Lysosomes/tears/secretions/saliva.2)Kills bacteria/contains antibacterial agent.3)Nasal hairs filter out pathogens.
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What are examples of primary defence in the ears?
1)Ear wax/ hairs 2)trap pathogens/ parasite.
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What are examples of primary defence in the respiratory system?
1)Mucus membranes/goblet cells.2)Produce mucus to trap pathogens/parasite.3)Cilia waft to remove pathogen.
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What are examples of primary defence in the Stomach/Vagina?
1)Gastric juice/stomach acid/acid in vagina. 2)Low/acidic PH.3)Kills pathogens/parasites by denaturing essential enzymes.
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What are examples of primary defences that are expulsive reflexes?
1)Coughing/sneezing expels pathogens from respiratory system.2)Vomiting/Diarrhoea- expels pathogens from digestive system.
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What are examples of primary defence in the skin?
1)Physical barrier to prevent entry of microorganisms.2)Platelets cause blood clotting.3)prevents pathogens/parasite entering blood stream.
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Describe blood clotting.
1)When a vessel is damaged, collagen fibres exposed and platelets stick to them.2)Leucocytes collect at site, release thrombokinase.3)This turns protein prothrombin into thrombin.4)Fibrin traps RBC and platelets-dry to form clot.5)Ca2+ ions required.
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What is thrombin?
An enzyme that hydrolyses fibrinogen into fibrin, a long insoluble molecule.
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What is non specific immunity?
Phagocytes able to digest/break down a range of different pathogens.
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What are two types of phagocyte?
1)Neutrophil.2)Macrophages.
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What are 4 types of White blood cell (Leucocyte)?
1)B Lymphocyte.2)C Lymphocyte.3)Neutrophil.4)Macrophages.
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Describe neutrophils.
1)Multi-lobed nucleus.2)Smaller than macrophages.3)Produced in bone marrow.4)Transported in blood.5)Squeeze out of blood into tissue fluid.
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Describe macrophages.
1)non lobed nucleus.2)Larger than neutrophil.3)Produced in bone marrow.4)Transported in blood.5)Called monocytes in blood and develop into macrophages in organs.
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Describe the action of phagocytes.
1)Phagocytic cells recognise pathogen as foreign, pathogen=antigenic.2)Pathogen engulfed by phagoctyosis/endocytosis.3)Go to vacuole.4)Lysosomes fuse to vesicle-release hydrolytic enzymes,pathogen digested.5)Useful products recycled.6)Waste excreted.
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What are examples of useful products from pathogens?
Amino acids, sugars, fatty acids.
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What are the defining features of a neutrophil?
1)Darkly stained lobed nucleus.2)Granular cytoplasm.3)Larger than erythrocyte.4)Smaller than monocyte.
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What are the defining features of an erythrocyte?
1)Smaller than WBC (leucocyte).2)No nucleus.
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What are the defining features of a monocyte?
1)Darkly stained non-lobed nucleus.2)Granular cytoplasm.3)Larger than erythrocyte.4)Larger than neutrophil.
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What is an example of a chemical released by infected cells?What does this cause?
1)Histamine.2)Attracts neutrophil to area, makes capillaries leaky.3)More fluid leaves capillaries at infection site-redness and swelling.
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What is an antigen?
A molecule that can stimulate an immune response, e.g. proteins and glycoproteins.
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What is a B lymphocyte?
1)Form part of cellular response to pathogens.2)Mature in bone marrow.3)Produce antibodies.4)Undergo clonal expansion.5)Fight bacteria.
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What are on the surface of B lymphocytes?
Specific receptors that are only complementary to one pathogens antigen.
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What are the 2 main stages in the role of B lymphocytes?
1)Clonal selection.2)Clonal expansion
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Describe clonal selection.
B lymphocyte is specific and complementary to the pathogens antigen. http://youtu.be/VlG8xGAOdvg
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Describe clonal expansion.
1)Mitosis occurs to produce large numbers of B lymphocytes plasma cells.2)Genetically identical copies- need specific receptor to fight infection.
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What are the two types of cells produced after clonal expansion .
1) Memory Cells-immunological memory. 2)Plasma cells.
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Outline the role of plasma cells.
1)Produce genetically identical antibodies.2)Antibodies are proteins and attack and destroy pathogens.
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What kind of structure do antibodies have?
Quaternary structure.
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Describe the variable region of an antibody.
1)Specific shape.2)Differs from one type of antibody to another.3)Shape determined by amino acid sequence.4)Shape of variable region complementary to antigen.
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Describe the hinge region of an antibody.
1)Allows flexibility.2)Allows branches of y-shaped molecules to move apart.3)Allows attachment to more than one antigen.
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Describe the constant region of an antibody.
1)Same in all antibodies.2)Enables antibody to attach to phagocytes.3)Helps in phagocytosis.
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What is agglutination?
1)When antibodies have many y-shaped molecules stuck together, so many antigen binding sites.2)Attach to many pathogens simultaneously and stick them together so they're too large to enter host cell.
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What is neutralisation?
1)When the antigen on the surface of pathogen may be used to bind to host cell.2)When antibodies bind to this antigen, the pathogen can't bind to the host cell.3)Antibodies can also bind to toxins and prevent these from entering host cells.
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What are T lymphocytes?
1)Form part of cellular response to pathogens.2)Mature in Thymyus.3)Secrete substances which kill infected cells.4)Undergo clonal expansion.5)Activate other lymphocytes.6)Fight viral infections.
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What is an APC?
An antigen presenting cell.
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Describe how macrophages aid T lymphocytes.
1)Non-specific immune response.2)Partially digests pathogen-doesn't break down antigen. http://youtu.be/dkZ5DbJg30M
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Describe clonal selection for T lymphocytes.
1)Receptors on surface complementary to antigen. OR 2)Antigen presented by APC. OR 3)Antigen presented on infected human cell.
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What does a pathogen antigen cause (when the rest of the pathogen has been digested by macrophages?
An immune response as it looks like the pathogen but doesn't make you sick.
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What occurs after clonal selection?
Clinal expansion.
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What 3 things does the T lymphocyte differentiate into?
1)Memory cells- immunological memory.2) T-killer cells. 3)T helper cells.
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Describe T-killer cells.
1)Deal with viral infections.2) Digest/kill our own infected cells.3)Uses HCl or H2O2 to kill infected cells.
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Describe T-helper cells.
1)Co-ordinate immune response.2)Release chemicals called cytokines-cause phagocytes to come to area and B lymphocytes.
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Link to explain immunological memory.
https://m.youtube.com/watch?feature=youtu.be&v=QoEut8ZwHHM
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Describe the first infection.
1)The pathogen breaks primary defence, goes into blood/tissue fluid.2)1-5 days before antigen is identified.3)Slow increase of antibody conc.4)Very few B lymphocytes.
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Describe the primary immune response.
1)Pathogens destroyed.2)No more B lymphocytes or memory cells being stimulated.3)Differentiation stops.4)No more plasma cells, no more antibodies.5)After 10 days symptoms gone, antibody conc. at highest.
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Describe the second infection.
1)Same pathogen and antigen.2)Lots of memory cells and specific lymphocytes.3)Higher chance of correct memory cell/lymphocyte encountering pathogen.4)Faster and bigger response, don't get ill.
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What happens to plasma cells when the pathogen goes?
The cells produce antibodies then die.
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What happens to memory cells when the pathogen goes?
Memory cells survive, stimulated by antigens.
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Card 2

Front

What are the 5 stages in the defence against pathogens summary.?

Back

1)Primary Defence- External barriers.2)Secondary Defence- Non-specific immune response.3)Secondary Defence- Specific immune response.4)Pathogen destroyed immune to specific antigen.5)Re-infection by antigen, memory cells= faster secondary response.

Card 3

Front

What is primary defence?

Back

Preview of the front of card 3

Card 4

Front

What are examples of primary defence in the eyes/nose/mouth?

Back

Preview of the front of card 4

Card 5

Front

What are examples of primary defence in the ears?

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Preview of the front of card 5
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