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FORENSIC SCIENCE Introduction to Toxicology

FORENSIC SCIENCE Introduction to Toxicology. What is involved in Forensic Toxicology?. Forensic toxicology helps determine: The cause/effect relationships between exposure to a drug or other substance The toxic or lethal effects from that exposure

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FORENSIC SCIENCE Introduction to Toxicology

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  1. FORENSIC SCIENCEIntroduction to Toxicology

  2. What is involved in Forensic Toxicology? Forensic toxicology helps determine: The cause/effect relationships between exposure to a drug or other substance The toxic or lethal effects from that exposure Toxicologists look for the presence of drugs &/or poisons They use bodily fluids & organs

  3. What is involved in Forensic Toxicology? • Toxicologists must understand metabolism (transforming chemical in the body to another chemical for the purpose of elimination from the body) • Reason: few substances enter and leave the body in the same chemical state (think digestion) • Toxicology example: heroin breaks down to morphine

  4. What is involved in Forensic Toxicology? • After the toxicologist has detected, identified and quantified (how much) a drug or poison, they must also determine the toxicity of the substance. • Toxicity-how strong it is • This is difficult since what is toxic to one person may not be to another person

  5. What are techniques used in toxicology? • First- selectively remove & isolate questioned substance • A large # of substances are isolated by using acids and bases • An acid is a compound capable of donating a hydrogen ion • A base is a compound that is capable of accepting a hydrogen ion • pH scale 0-6.9= acid and 7.1-14 = base; 7 is neutral

  6. What are techniques used in toxicology? • Testing is in two parts: screening or presumptive testing and then conclusive or confirmative testing • Screening/presumptive: done first; doesn’t identify the substance, just tells you what it MIGHT be; usually a color change test • Conclusive/confirmative: done in lab; identifies specific componenets

  7. Hmm.. Things to think about • Less than ½ to 1% of homicides result from poisonings • Accidental drug overdoses are more common • More than 50% of the federal prison population and about 20% of the population in state prisons consists of drug offenders

  8. Fastest way to get toxins to the brain The fastest way to get a drug to the brain is by smoking it. When a drug like tobacco smoke is taken into the lungs, nicotine seeps into the lung blood where it can quickly travel to the brain. This is one reason why smoking cigarettes is so addicting is due to the fast delivery

  9. Getting toxins to the brain • Injecting a drug directly into a blood vessel is the second fastest way to get a drug to the brain followed by sniffing it through the nose. The slowest mode of delivery is by ingestion, such as drinking alcohol. The effects of alcohol take several minutes rather than a few seconds to cause behavioral & biological changes in the brain

  10. What about drug dependence? • Psychological dependence: conditioned use of drug caused by emotional needs • Physical dependence: results in withdrawal symptoms and sickness (ex: headaches when caffeine is removed from diet until body becomes used to its absence)

  11. Drug Lingo you need to be familiar with

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