Principles of Toxicology Flashcards
What is toxicology?
the study of adverse effects of chemicals on living systems
What is toxicity?
the capacity of a substance to produce injury under defined conditions of route, dose, and duration of exposure
What is toxicokinetics?
rates of absorption, distribution, excretion, and metabolism of toxicants
What is organ toxicity?
alternation in cell structure or function
What is carcinogenesis?
derangement of cell reproduction and growth of cells
What is mutagenesis?
formation of changes in genetic material
Teratogenesis?
toxicant-induced formation of birth defects
Reproductive toxicity?
effects on fertility, rates of conception and embryonic or fetal toxicity
What is volume of distribution equal to?
Dose/plasma concentration. small Vd is remains in blood, high Vd if enters tissue
What is clearance?
Urine concentration * Rate /
Plasma concentration
What is total clearance?
hepatic clearance + pulmonary clearance + kidney clearance…
What is exposure a function of?
concentration of toxicant and length/time of the exposure
Define the following type of exposures: acute, subacute, subchronic, and chronic.
acute - singe exposure, then chemical removed
subacute: exposure up to 1 month
subchronic: 1-3 months
chronic: long term (2 years in a rodent)
What is a hypersusceptible dose response?
individual that responds to very low doses of a toxicant. Shift to the left of dose response curve.
What is a resistant dose response?
individual responds to only very high doses of drug. Shift to right of dose response curve
What is potency?
mg/kg necessary for an effect to occur
What is effectiveness?
Maximal effect tissues can produce
What is hormesis?
Dose range with very desirable effect but too little does not protect body or too much has very deleterious effects. This occurs with vitamins.
What is an additive chemical reaction?
2+3 = 5
What is a synergistic chemical reaction?
2+3 = 20, ex) alcohol and tylenol
What is potentiation in a chemical reaction?
0 + 3 = 20. Ex) carbidopa/levodopa
What are different types of antagonistic chemical reactions?
Functional - sympathetic & parasympathetic; Chemical - chelation;
Dispositional - alter uptake, protein binding, excretion;
Receptor- agonist + antagonist
What are the factors affecting toxic responses?
SHADED: Sex (pregnancy, hormones); Host factors; Age; Diet; Environment; Diseases of liver and kidney (metabolism & excretion)
What is risk vs. safety?
Risk is the probability that a substance will produce harm under specified conditions and safety is that probability that harm will not occur
