PED1003 8 TOXICOLOGY EXAM QUESTIONS AND ANSWERS
WITH COMPLETE SOLUTIONS GRADED A++
what is toxicology
noxious effects of chemicals on living systems
xenobiotics
foreign chemicals the organism doesn't produce
simplest way to measure its toxicity is its LD50
what is an LD50
lethal dose for 50% of the population (e.g.rats in lab)
in acute toxicity, symptoms develop _______ whilst chemical is ____ __ ____ and
are _____ lived, may still be lethal. can be short/long exposure. may be treated
with ________
rapidly
still in body
short
antidote
why is causative agent easily identified in acute toxicity
chemical is still in body
in chronic toxicity, symptoms are _______ after chemical is excreted, and is
detected retrospectively such as ___________. may be a _______ effect from long
term exposure. chronic effects may also occur from single acute exposure
, delayed
epidemiology
cumulative
what is the exposure site of toxic drug
where it enters the blood e.g GI tract, bite, injections site
aim of xenobiotic metabolism
to transform lipophilic compounds into hydrophilic compounds which can't cross
membranes meaning their more easily excreted.
Where are orally administered drugs absorbed? what does this depend on
buccal/oral mucosa, stomach, small intestine
pH differs in these compartments/ differences in ionisation state of drugs
initial drug distribution is quick as blood flows to organs/ tissues, what is
subsequent uptake dependent on
affinity
-ability to cross membranes
-specific transporters (influx/efflux)
-protein binding
How is xenobiotic metabolism achieved?
inserting functional groups which aid conjugation to high MW, water soluble (or even
ionisable) compounds
what 2 sites does deconjugation of a metabolite take place
bile
bladder
WITH COMPLETE SOLUTIONS GRADED A++
what is toxicology
noxious effects of chemicals on living systems
xenobiotics
foreign chemicals the organism doesn't produce
simplest way to measure its toxicity is its LD50
what is an LD50
lethal dose for 50% of the population (e.g.rats in lab)
in acute toxicity, symptoms develop _______ whilst chemical is ____ __ ____ and
are _____ lived, may still be lethal. can be short/long exposure. may be treated
with ________
rapidly
still in body
short
antidote
why is causative agent easily identified in acute toxicity
chemical is still in body
in chronic toxicity, symptoms are _______ after chemical is excreted, and is
detected retrospectively such as ___________. may be a _______ effect from long
term exposure. chronic effects may also occur from single acute exposure
, delayed
epidemiology
cumulative
what is the exposure site of toxic drug
where it enters the blood e.g GI tract, bite, injections site
aim of xenobiotic metabolism
to transform lipophilic compounds into hydrophilic compounds which can't cross
membranes meaning their more easily excreted.
Where are orally administered drugs absorbed? what does this depend on
buccal/oral mucosa, stomach, small intestine
pH differs in these compartments/ differences in ionisation state of drugs
initial drug distribution is quick as blood flows to organs/ tissues, what is
subsequent uptake dependent on
affinity
-ability to cross membranes
-specific transporters (influx/efflux)
-protein binding
How is xenobiotic metabolism achieved?
inserting functional groups which aid conjugation to high MW, water soluble (or even
ionisable) compounds
what 2 sites does deconjugation of a metabolite take place
bile
bladder
