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B2: Keeping Healthy key terms and definitions
Pathogens The microorganisms that make us ill.
Bacteria A type of pathogen which can be treated by antibiotics.
They reproduce rapidly once in the body.
Virus A type of pathogen which can't be treated with
antibiotics. Viruses need a host cell to be able to
Antigens Pathogens carry antigens on their surface that
antibodies recognise as being foreign.
White blood The body's immune system is made up of these. There
cells are two types:
Phagocytes these engulf and digest pathogens
and toxins, or they release an enzyme to destroy
pathogens and toxins
Lymphocytes each lymphocyte carries a specific
antibody. When this antibody meets the right
antigen it quickly releases antibodies to
neutralise pathogens. This is done by: binding to
pathogens and destroying them, coating them
and sticking them together so phagocytes can
digest them easier or release chemical signals so
phagocytes can come and digest them.
Epidemic An outbreak of disease where a large amount of the
population is infected.
Antibiotic A drug used to treat bacterial infections by killing
bacteria or stunting their growth.
Superbug If the bacteria becomes resistant to antibiotics you
have been prescribed this can give you a "superbug"
which is more dangerous as it can't be treated with
Example: MRSA is a more common superbug, it can
be fatal as MRSA is resistant to all antibiotics.
Vaccination When a safe form of diseasecausing microorganism is
injected into a person so if they become infected with
this disease they would have memory cells to fight it
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Memory cells After you have first been infected with a disease,
memory cells are created so if you become reinfected
with the same disease memory cells will produce the
right antibodies quickly.
"Open label" A drug trial where both the researcher and volunteer
trials know what they are being given
A "blind" trial A drug trial where the researcher knows what the
volunteer is receiving but the volunteer doesn't.…read more
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Heavy drug use (including alcohol)
Not exercising enough
Epidemiologica An epidemiological study is the study into lifestyle
l studies factors across the population to see what lifestyle
factors increase the risk of certain diseases
Homeostasis The process that maintains a constant internal
Example: Homeostasis is used to keep a constant
temperature inside the body
Negative Negative feedback ensures that, in any control system,
feedback changes are reversed and returned back to the set