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Unformatted text preview: 1 Toxicology II Randy Treadwell Dept. of Environmental and Occupational Health Sciences UW School of Public Health and Community Medicine What is Toxicology? z The study of adverse effects of chemicals on living organisms. – Individual cells – Cell cultures – Animals – Humans www.sciencemuseum.org.uk Toxicological Definitions z Poison: – A substance that produces serious illness or death in relatively small doses. z Toxin: – A poisonous substance that has a biological origin. z From animals, plants, bacteria z Toxicant: – Any substance that produces toxicity after exposure. Often refers to human-made substances. Toxicological Definitions, cont. z Venom: – Toxic substance secreted by animals. z Xenobiotic: – “xeno” based on Greek word “xenos”=stranger. – Any substance that is “foreign” to the body. z Anything that is not produced naturally by the body. “The dose makes the Poison!” z "All things are poison and nothing is without poison, only the dose permits something not to be poisonous.-Paracelsus (1493-1541) LD50 Oral Rat: >90 ml/Kg dbhs.wvusd.k12.ca.us ADME: How do Toxicants act? z Absorption – Toxicant enters the bloodstream. z Distribution – Toxicant “translocates” (moves) throughout body. z Metabolism – Toxicant is “biotransformed.” – Not all toxicants are metabolized! Example: Water. z Excretion – Toxicant eliminated from body. 2 Absorption of Toxicants z The process by which toxicants cross body membranes and enter the bloodstream. – GI Tract – Lungs – Skin – Special “parenteral” administration: IV, IM, subcutaneous. intmed.muhealth.org/ Distribution of Toxicants z Toxicants move fairly rapidly to tissue or organ targets – Rate is limited by blood-flow....
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- Fall '07
- Toxicology, Poison, match, Phosphorus, Toxicants, phossy jaw