Chapter 10 10.1 Forensic Toxicology

Objectives Explain how alcohol is absorbed into the bloodstream, transported throughout the body, and eliminated by oxidation and excretion.

Alcohol The most heavily abused drug in the US 40% traffic deaths (17,500) are alcohol related Hospital treatment exceeds 2,000,000 persons per year

Toxicologists Responsible for detecting and identifying the presence of drugs and poisons in body fluids, tissues, and organs Services used in crime labs, medical examiner’s offices, and hospitals Various systems exist across the country Role limited to matters that pertain to violations of criminal law

Toxicology of Alcohol Ethyl alcohol is a colorless liquid diluted with water Logically most obvious measure of intoxication would be amount of liquor consumed but such information is not normally available to law enforcement

many factors influence intoxication level - i. e many factors influence intoxication level - i.e. body weight, rate of alcohol absorption in body Alcohol is a depressant, primarily effecting the central nervous system and brain

Effect is proportional to concentration of alcohol in nerve cells Most susceptible areas = forebrain Later functions of central and rear brain affected Most resistant and last to fail is brain’s medulla Regulates vital functions of respiration and heart activity

Toxicologists focus attention on concentration in blood as blood provides the medium for circulation of alcohol through the body Blood alcohol levels are directly proportional to the concentration in the brain

Alcohol appears in blood moments after consumed Concentration increases as alcohol is absorbed from stomach and small intestine into blood stream

Rate of alcohol absorption into the bloodstream depends on: Time taken to consume the drink Alcohol content of the beverage Amount consumed Quantity and type of food consumed at the time of drinking

Absorption process completed usually 30-90 minutes after final drink Absorption process is difficult to predict Alcohol enters blood and is carried to all parts of the body Distributed uniformly in water portions of body Low content in fat, bones, and hair

Post-mortem examinations use water-rich organs and fluids to determine alcohol content Brain, cerebrospinal fluid, vitreous humor

10.1 Questions – answer on a sheet of notebook paper What is the most widely abused drug in Western countries? What is a toxicologist? Name three settings in which a toxicologist often works. Name at least three factors that influence the rate at which alcohol is absorbed into the bloodstream. In what parts of the body does alcohol tend to accumulate? Why does it accumulate in these places?