Principles of Toxicology Flashcards

1
Q

what does TD50 tell you

A

median toxic dose

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

what values are plotted on a graph to show the relationship between exposure and response

A

response (% of the population) against log10 dose

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

what does NOAEL stand for

A

no observed adverse effect level

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

which sort of toxicants do not have a dose below which no adverse respose is evoked

A

carcinogens and mutagens

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

what shape is the curve of a graph showing a toxicant that demonstrates hormesis

A

U or J

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

what does a steep slope on the dose/response graph suggest about the toxicant

A

a small change in exposure ellicits a large change in toxicity ie high affinity toxin

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

what are the 4 aspects of exposure

A

route, intensity, frequency and duration

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

what is meant by bioavaailability

A

the extent to which a drug or other substance is taken up by a specific tissue or organ after administration

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

what are the main routes of entry of a toxicant

A

ingestion and absorption from GI tract, inhalation and absorption from lungs or absorption through skin

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

what is the key property of a toxicant which determines its ability to be absorbed

A

lipid solubility

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

what are the ways in which toxicants can be removed by the body

A

excretion in urine, bile or exhaled air
by metabolism
accumulation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

under what cicumstances does accumulation of a toxicant become threatening

A

during starvation due to breakdown of fat stores

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

name an example of a toxicant which is not absorbed by diffusion, but instead is transported

A

paraquat

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

does carbon monoxide bind haemoglobin reversibly or irreversibly

A

reversibly

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

do organophophate nerve gases bind irreversibly or reversibly to acetylcholinesterase

A

irreversibly

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

how does binding of a toxicant to a target cause illness generally

A

it alters target function and cell homeostasis

17
Q

under what circumstances is a toxicant less likely to compromise the fntion of a target cell/tissue/organ

A

if the target can be rapidly regenerated or is well protected

18
Q

give 2 examples of drugs which elicit hormetic responses

A

biochanin A and brommodioxyuridine

19
Q

what is the target tissue of paraquat

A

lung eputhelia

20
Q

where is paraquat and other toxins stored when accumulated

A

fat tissues

21
Q

give an example of a drug which metabolites are more toxic

A

paracetamol

22
Q

how does metabolism increase the ability to excrete toxicants

A

alters lipid solubility

23
Q

what are the 4 circumstances of exposure to toxicants

A

environment
accidental/intentional
treatment of illness
occupational

24
Q

what are the 4 methods of movement across the epithelia

A

transcellular (across membrane)
carrier mediated
paracellular (through gaps)
endo/exocytosis

25
name a toxin which crosses the epithelia via carrier mediated method
arsenic
26
how is botox transported across the epithelia
endo/exovytosis
27
how is NOAEL used to calculate the starting dose in clinical trials
NOAEL/100 as 10x more sensitive and 10x slower at removing toxicant than animals
28
what does the threshold of toxicological concern estimate?
quantitatively estimates the size of the population, the intensity, duration and frequency of exposure and the routes of entry
29
what must be carried out if exposure is likely to be higher than TTC
further risk assesment
30
which populations are generally more susceptible to toins
children and elderly
31
which population are more susceptible to toxicity from acetyl due to 90% of them being fast metabolisers
asian
32
when is something deemed to be "safe"
if risks are judged to be acceptable
33
what is REACH
registration, evaluation and authorization of chemicals
34
when was REACH introduced and who by
june 1st 2000 | EU
35
what is the purpose of REACH
to improve protection, a more transparent system for risk assessment and control of chemicals
36
does REACH promote non-animal testing
yes