module 1: section 2 Flashcards
(25 cards)
how are toxicants classified by:
adverse effect, their use, their target
allergic reaction?
immune-mediated responses to exposure to a chemical/xenobiotic. Previous exposure resulted in sensitization
Describe how an immune response is conducted through allergic reactions
A toxicant/hapten is joined by an endogenous protein resulting in an antigen which is then detected and antibodies are produced
what is an idiosyncratic reaction?
an unusual toxic response to xenobiotic exposure that is only observed in small numbers of people.
what are traits of idiosyncratic reactions?
-genetic in nature, not immune-mediated
- similar in nature to response seen in average person but differs in severity of response
What is immediate toxicity
A toxic effect is produced quickly following a single or short-term exposure
what is delayed toxicity?
a toxic effect is produced some time after an exposure
What is reversible toxicity?
toxic effects can be reversed by the body either repairing or removing associated damage
what is irreversible toxicity?
when the body is incapable of repairing or removing damage caused by a xenobiotic agent
What does reversibility depend on?
-regenerative ability of the organ that has been damaged
-dosage and duration of exposure
what is local toxicity?
a toxic response that occurs at the site of contact with the toxicant
what is systemic toxicity?
toxicant produces toxic effects throughout the body
what is tolerance?
the diminished response that accompanies exposure to a chemical to which the person has already been exposed
what causes tolerance?
-decrease amount of toxicant reaching the site of action
-reduction in the response of the tissue to a toxicant
what is chemical interaction?
the exposure of 2+ chemicals, affecting the response to exposures.
What are the 4 types of chemical interactions?
- addition
- potentiation
- synergism
- antagonism
addition
the total toxic response is equal to the individual responses added together
potentiation
the exposure of a chemical alone doesn’t produce a response, but with another it increases the toxicity
synergism
total toxic response is greater than the individual responses added up
antagonism
interference of chemicals actions , both affected or one affects the other
what are the 4 types of antagonism?
- receptor
- functional
- dispositional
- chemical
receptor antagonism
2 chemicals compete for the same site on a receptor, preventing the effects of either or both
functional antagonism
2 chemicals act in opposite ways, cancelling each other out
dispositional antagonism
results in a change in the behaviour of the chemical(s)
