History of Toxicology, Dose Response Flashcards
What is toxicology?
Study of adverse effects of chemicals on living organisms.
What are the disciplines of toxicology?
Mechanistic Descriptive Regulatory Forensic Clinical Environmental
What disciplines of toxicology form risk assessment?
Mechanistic, Descriptive, Regulatory
What is toxicity?
Ability to produce adverse effect on humans or animal organ/systems.
- Depends on route of exposure, dose, test system
- Not altered by handling, temperature
- Intrinsic property of chemical
All chemicals are toxic, T or F?
True, all chemicals have the potential to be toxic
What is the definition of a hazard?
Toxicity plus other factors
- Physical and chemical
- Exposure related
- Individual susceptibility
- Bioavailability
Who is the father of toxicology?
Paraselsus; first to associate dose with response
What factors influence dose?
- Route and site of exposure
- Duration and frequency of exposure
- Bioavailability
Routes of exposure?
Oral, inhalation, dermal, ip, im, iv
Foundation response types?
Allergic reactions - immediate and delayed response
Local - irritation response
Systematic - target organ damage
Types of dose responses?
Individual or graded response
Quantal or grouped data
What happens at the top of the sigmoid or s-curve?
Levels off when everything has produced a response
What is a probit curve? NED?
A normalization technique. Normal equivalent deviate (NED) - the # of standard deviations from the mean.
Dose-response relationships?
- S-shaped curve
- U-shaped curve
- Thresholds
What is hormesis?
A “U” shaped dose response relationship where there is an optimal dose (i.e. Essential nutrients)
