immunology

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describe a non-specific defence mechanism.
defence is immediate and the same for all pathogens.
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how are lymph nodes involved?
the contain a conc of phagocytes and they prevent infection spreading to other parts of the body.
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how is the thymus involved?
it activates T lymphocytes
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how is the spleen involved?
it has phagocytes which filter blood
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how is the appendix involved?
it has lymphoid tissue that helps to protect the digestive system
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how are the tonsils involved?
they have lymph nodes that protect the respiratory system
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how is skin involved?
it is a physical barrier that most pathogens find hard to penetrate
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how is mucus involved?
pathogens stick to it and it is swallowed into the stomach
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how is stomach acid involved?
the enzymes of the pathogens are denatured therefore the organisms are killed
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give 2 other examples of non-immune response.
-inflammation. -fever.
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describe specific response.
it is slower and is specific to each pathogen and provides long lasting immunity.
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what two forms does it occur in?
cell-mediated response and humerol response
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what do phagocytes do?
ingest and destroy pathogens.
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why do large particles have to be engulfed?
they are too big to cross the cell-surface membrane by diffusion or AT
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describe phagocytosis.
chemotaxis attracts phagocyte to pathogen > pathogen moves along conc gradient and binds to phagocyte > phagosome forms > lysosomes release lytic enzymes into phagosome > bacterium digested > break down products absorbed by phagocyte
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what do T-lymphocytes respond to?
the bodies own cells that have been invaded by non-self material - antigens attached to the bodies cell
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where are they made and where do they mature?
made = bone marrow, mature = thymus gland
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describe the process of cell-mediated immunity.
pathogens invade body cells/taken in by phagocytes > antigens presented on cell surface membrane > receptors on helper t-cells fit onto antigens > T cells divide rapidly by mitosis to form clones > differentiate
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what do they differentiate into?
-memory cells. -suppressor cells (stimulate phagocytosis). -helper cells (stimulate humerol response). -killer cells.
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what do B-lymphocytes respond to?
helper T cells
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where are they made/do they mature?
in the bone marrow
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describe the process of humerol immunity.
surface antigens taken up by B cells > process and present antigens on their surface > helper T cells activate B cells to divide > clone of plasma cells > produce antibodies > destroy pathogen > some differentiate
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what do they differentiate into?
memory cells that circulate in humour
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what do plasma cells do?
secrete antibodies directly and destroy pathogens/toxins and only live for a few days
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what do memory cells do?
when they encounter the same antigen again they rapidly divide into plasma cells and more memory cells and can last for decades
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what is antigenic variability?
when some pathogens have a lot of strands, and this means that the antigens they are made of are constantly changing
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what is the result of this?
memory cells are useless as the antibodies do not fit so they are treated with the slower primary response
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what is the primary response?
occurs the first time an antigen is encountered. -slow. -symptoms are evident.
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what is the latent period?
the period between infection and the onset of antibody production
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what happens after the latent period?
conc of antibody in the blood rapidly rises then falls
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what is the secondary response?
-occurs if the body encounters the same antigen again. -rapid. -produces more antibodies. -immunity required because pathogen is destroyed before it fully infects body.
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what is an antigen?
a substance of a cell that is part of a pathogen.
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what is it recognised as and what does it cause?
non-self, causing an immune response
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what is an antibody?
a globular protein produced by a B cell that can bind with a particular antigen
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what are monoclonal antibodies?
antibodies produced by a single B cell produced in large amounts in the lab
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how are they obtained?
mouse given antigen by injection > B cells produce antibodies > B cells extracted from spleen > mixed with myeloma (tumour) cells to form hybridoma cells > screened for antibody production > antibodies produces on large scale
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why are they mixed with myeloma cells?
B cells can't live and divide outside the body for long but myeloma cells can
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how are they accepted by the human body?
they are humanised
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how are they used today?
-to identify molecules to a high specificity. -in pregnancy tests. -cancer drugs.
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what does an antigen contain?
a antigen from a weakened/dead form of organism
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what does it stimulate?
a primary response then if person infected again a secondary response is stimulated by memory cells
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what is active natural immunity?
immunity that develops due to natural exposure to an antigen > long-lasting
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what is active artificially induced immunity?
immunity that develops following immunisation > long-lasting
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what is passive natural immunity?
immunity that develops through the transfer of antibodies from mother to baby through breast milk or the placenta, but no memory cells are formed > short-lasting
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what is passive artificially induced immunity?
immunity that develops after infection but no memory cells develop > short-lasting
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why so vaccinations not eliminate a disease?
-defective immune systems. -if disease develops immediately after vaccination. -antigenic variability. -pathogens can 'hide' from the immune system. -those who object for religious/ethical reasons
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what are the features of a successful vaccination programme?
-cost effective. -quick/easy to administer. -properly tested. -benefits outweigh side effects. -easy to store/transport. -possible to induce her immunity.
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what is % cover?
-the proportion of individuals that must be immune in order to prevent an epidemic
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Card 2

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how are lymph nodes involved?

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the contain a conc of phagocytes and they prevent infection spreading to other parts of the body.

Card 3

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how is the thymus involved?

Back

Preview of the front of card 3

Card 4

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how is the spleen involved?

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Card 5

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how is the appendix involved?

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