Tox 300 midterm 2 Questions and Correct
Answers/ Latest Update / Already Graded
toxicodynamics
Ans: process of interaction of chemical substances with target
sites and the subsequent reactions leading to adverse health
effects. what the xenobiotic does to the body.
idiosyncratic effects
Ans: genetically based toxic reactions that occur only in small
proportions of individuals with no known cause
spectrum of toxic effects: local vs systemic
Ans: systemic: in the systemic circulation, can be distributed to
other organs
local: seen with strong acids and caustic substances, as well as
inhaling toxic gases like chlorine or ammonia
spectrum of toxic effects: reversible vs irreversible
Ans: most toxic effects are reversible. cancer or teratogenic
effects are irreversible.
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spectrum of toxic effects: immediate (acute) vs delayed (chronic)
Ans: acute = hours to days. e.g. chlorine gas. acute toxic effect.
delayed = cancer, something that takes months to years to set
on.
spectrum of toxic effects: morphological, functional, and biochemical
effects
Ans: 1. morphological effects are commonly irreversible. can
be effects to limbs, or effects to morphology of cells.
2. functional: toxicant can affect a critical function in the body,
e.g. liver/kidney function. generally reversible effects.
3. vast majority of xeno effects are initiated by some type of
molecular event. e.g. cancer is initiated by cellular dysfunction.
spectrum of toxic effects: allergic vs idiosyncratic reactions
Ans: 1. hypersensitivity/allergic reactions: initially exposed to
an antigen (e.g. bee venom) can get delayed hypersensitivity.
2. idiosyncratic reactions: genetically based toxic reactions t hat
occur only in small proportions of individuals with no known
cause
spectrum of toxic effects: graded (continuous) vs. quantal (all or none)
responses
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Ans: 1. continuous data have an infinite # of values: e.g. body
weight
modifying factors of toxicity: dose
Ans: dose defines the poison
modifying factors of toxicity: duration and frequency of exposure
Ans: e.g. smoking one cigarette vs a pack a day for several
years. can be important in workplace exposure where you
cannot avoid constant exposure.
modifying factors of toxicity: species, genetic strain, individual
Ans: interspecific differences - difficult to say effects in one
species will translate to effects in another. due to enzymes,
receptors, etc
modifying factors of toxicity: sex, pregnancy
Ans: differences between males and females usually related to
differential expression of genes. males are much more
susceptible to heart disease - thought that estrogens have a
protective effect.
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