Toxicology Flashcards
What is included in the job of a forensic toxicologist?
The job of a forensic toxicologist includes examining effects of a harmful substance on the body, determining how much/ what substances are present, determining how long it has been in someone’s body and considering how this harmful substance gets into someone’s body?
What types of body fluids are tested?
Blood, obtaining blood samples may be intrusive and even expensive, but it is considered as the most accurate method compared to testing other body fluids.
What are the routes of exposure?
Inhalation, ingestion, absorption, injection.
What are people commonly poisoned with?
Alcohol
At what BAC is someone legally intoxicated?
.08 BAC as the legal measure of intoxication for driving and for commercial truck drivers and bus drivers it is .047.
How does alcohol enter the bloodstream? What might affect the rate at which alcohol enters the bloodstream?
Alcohol is absorbed through the bloodstream from the stomach and (mostly) small intestine. The food you eat or have eaten can affect this, mostly by the dose of ethanol ingested and rate of consumption.
Other factors contributing to BAC are gender, body mass and composition, food effects, type of alcohol, and chronic alcohol exposure.
What happens once the alcohol enters the bloodstream (where does it go)?
Once it enters the bloodstream it goes through three stages. After absorption through the bloodstream, stomach, and small intestine, it is distributed evenly through watery portions of the body, and then eliminated when liver enzymes metabolize alcohol into a less toxic substance.
What are some of alcohol’s effects as BAC increases?
Feeling of well-being, relaxation, lower inhibitions, and sensation of warmth. Euphoria. Some minor impairment of judgment and memory, lowering of caution. Slight impairment of balance, speech, vision, reaction time, and hearing. When BAC reaches high levels, blackouts (gaps in memory), loss of consciousness, and death can occur.
What is done if someone is pulled over for suspected impaired driving?
Preliminary tests are performed to determine if evidentiary tests are necessary. These tests include, horizontal gaze nystagmus, walk and turn, and one let stand.
What is the relationship between the concentration of alcohol affecting the brain and the concentration elsewhere in the body (like blood or breath)? So what does this mean for collection of samples for testing?
For blood testing, they use a nonalcoholic disinfectant and anticoagulants and preservatives are added for refrigeration. Then post mortem blood is collected from multiple sites, heart, arteries in leg, and arm. The alcohol testing in breath indirectly determines the amount of alcohol, then they can use infrared absorption (like spectrophotometer), and fuel cell analysers which in field measurement of blood alcohol was used to evaluate a small pocket size blood alcohol analyser whose function is based on the fuel cell principle.
What are the different types of dependence?
Psychological dependence which is when an intense craving for drugs occurs and physiological dependence where drugs produce physiological changes that encourage further use.
How are drug schedules determined? Which schedule is the most restricted?
5 Schedules of drugs, federal law recognizes the 5 schedules of drugs based on accepted medical use and their abuse or dependence potential. (Controlled Substance Act)
Schedule I drugs are the most restricted and cannot be prescribed at all, because they have a high potential for abuse
How do hallucinogens effect the body?
Hallucinogens, causes marked alterations in normal functions these include; marijuana, LSD, MDMA.
How do narcotics effect the body?
Narcotics, used for relief of pain and sleep, analgesics, relieves pain by depressing central nervous system receptors. Source is opium (morphine) and also man-made opioids (oxycodone).
How do depressants effect the body?
Depressants depresses the central nervous system and calms anxiety and induces sleep, these include alcohol, barbiturates and inhalants.
How do stimulants effect the body?
Stimulants stimulate the central nervous system and provide a sense of well being and increased awareness. Extended use leads to strong psychological dependence. This includes cocaine and methamphetamine.
What are the two categories of drug tests?
Screening tests which are useful in the field, this includes marquis, dillie-koppanyi, Van Urk, and the Scott Test. And microcrystalline tests, when a reagent is added which forms crystals. The size and shape of the crystals are examined under a microscope.
Colors associated with Marquis test
turns purple in the presence of opium and orange-brown in the presence of most amphetamines
Colors associated with the Dillie-Koppanyi test
violet blue in the presence of barbiturates
Colors associated with Van Urk
turns blue-purple for LSD
Colors associated with Scott Test
3 solutions that turn blue, pink, blue in the presence of cocaine
Spectrophotometry
selective absorption of light by drugs, UV which can establish probable identify of a drug and IR which can specifically identify a substance
Chromotography
separates the drug from diluents
Mas spectrometry
after components are separated using chromotography they can be identified using machines
Marijuana identification
botanical features of Cannabis sativa L are viewed under a microscope
Screening tests are used
first to exclude certain drugs
confirmation tests are used
to identify a single substance
Anabolic Steriods
similar to testosterone that promotes tissue growth and division
Doping
use of a substance to enhance athletic performance
acute
single dose (seen within days)
toxicity
how harmful a substance is to a person (many factors can influence)
chromic
exposure over a long period of time (months to years)
poisons v toxins
poisons are natural or manufactured and toxins are nature like mushrooms or venom
