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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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This note was uploaded on 05/02/2008 for the course ENVL 111 taught by Professor Unknown during the Fall '07 term at University of Washington.
- Fall '07