forensic toxicology of alcohol

Question 1

forensic toxicology

Answer 1

how drugs and poisons affect humans
when a person ingests a drug or a poison it is absorbed into the bloodstream circulates through the body has intended and unintended effects and then is eliminated
f

Question 2

forensic toxicologists

Answer 2

deceased
help determine COD
living
usually drunk or drugged driving cases

Question 3

drug

Answer 3

chemical or chemical mixture that is designed to have one or more physiological and or psychological effects on a person

Question 4

poison

Answer 4

substance that has a toxic life threatening effect on a person

Question 5

forensic toxicologist

Answer 5

determines the identity of all drugs and poisons present in the body
determines the quantities of drugs and poisons present in body
determines metabolites secondary products of drugs present
determines interactions of drugs present
helps determine history or pattern of drug use by the person involved

Question 6

pharmacokinetics

Answer 6

how drugs move into and out of body
four processes taking place
absorption
passage of the drug through a tissue layer of the body
distribution
dispersion of the drug throughout the body
metabolism
process by which drug is chemically changed to a chemically different but related substance, metabolite
elimination
method of removing drug from body

Question 7

absorption

Answer 7

introduced by a number of means
oral intramuscular intravenous rectal topical subcutaneous inhalation
chemical nature and form of drug determines how easily it crosses tissue barrier
aspirin coated for slower absorption
may be controlled to reduce unwanted side effects
once the barrier is breached the drug will enter the bloodstream
oral ingestion is absorbed through the stomach or small intestine and the rate can be affected by other stomach contents

Question 8

distribution

Answer 8

drugs are distributed through bloodstream
blood reaches every cell of body
although the blood stream reaches all tissues this doesn’t mean that the blood is the same concentration everywhere
more blood goes to some orgnas
some drugs have preferential attraction to certain tissue

Question 9

metabolism

Answer 9

serves three purposes
deactivate the drug to have less effect
may be more soluble an easier to eliminate
ma convert substance that can be used by body’s cells for energy and easier elimination
mostly takes place in the liver

Question 10

elimination

Answer 10

predominately done through excretion in urine
drug must be water soluble, generally accomplished by liver
may also be done through respiration or perspiration if drug is volatile

Question 11

pharmacodynamics

Answer 11

how drugs act in the body
some organs have receptors
drugs bind with certain receptors
receptor fulfills a particular function or process

Question 12

agonist

Answer 12

drug that binds to receptor and causes the process

Question 13

antagonist

Answer 13

drug that binds to receptor and does not cause the process
can block or reverse action of agonist
heroin and narcan

Question 14

tolerance

Answer 14

phenomenon where he body organ systems adapt to drug
caused by decrease in sensitivity or number of receptors

Question 15

synergism

Answer 15

effect of two or more drugs being greater when taken together than their effects separately
alcohol and barbituates
bot CNS depressants

Question 16

identification of drugs in the body

Answer 16

may be difficult to do once ingested and distributed
small doses conc may be low
some drugs prefer certain tissues, hard to find

Question 17

steps for identification

Answer 17

sampling, extraction, screening, confirmation

Question 18

sampling

Answer 18

urine is used to screen for drugs
blood confirms presence of drug and determines its conc
hair can trap and hold drugs for as long as hair is on the body

Question 19

extraction

Answer 19

once a tissue or liquid (blood or urine) has been removed
drug must be extracted
makes analysis easier
keeps interment clean and unglogged
concentrates drug so it is easier to detect

Question 20

liquid phase extraction

Answer 20

separates liquids based on pH
not appropriate for a mixture of drugs with similar pH values
will be extracted together and not separated

Question 21

solid phase microextraction

Answer 21

useful for mixtures with similar pH values
specifically coated wire is inserted into fluid with drugs
drugs are selectively adsorbed onto wire
drugs eluted for further analysis

Question 22

screening

Answer 22

preliminary test for drugs in the body fluids
useful if you don’t know what drugs were ingested
panel of the most commonly abused drugs
two types
chromatographic tests
thin layer chromatography
gas chromatography
immunoassay tests

Question 23

immunoassay tests EMIT

Answer 23

similar to species test for blood
EMIT
enzyme multiplet immunoassay test
uses drug antibodies aded to evidence sample
antibodies bind to drug if present
known amount of the suspended drug that has been labeled with an enzyme is added and any unbound antibodies bind
this enzyme labeled drug is measured and correlated to the concentration of the antibodies
determining the amount of drug

Question 24

immunoassay tests RIA

Answer 24

radioimmunoassay
similar to EMIT, but antigens are radioactively labeled

Question 25

confirmation

Answer 25

mass spectrometry is the accepted method of confirmation
laboratories have cut off levels
lowest level possible to say that a drug is present
negates noise mistakes for an analytical signal

Question 26

alcohol two measuring systems

Answer 26

blood alcohol conc BAC
breath alcohol conc BrAC
operating motor vehicle while under influence is illegal .08%
directly tied to conc of alcohol in body

Question 27

forensic toxicology of alcohol

Answer 27

once ingested
absorbed white quickly into bloodstream
faster it is absorbed, higher BAC
drink strong drinks quickly, BAC increases rapidly
drink weak drinks slowly BAC will increase slower
alcohol is absorbed mostly through small intestine, sometimes stomach and mouth

Question 28

factors that affect rate of absorption for alcohol

Answer 28

nature of drink, strong v weak
rate and speed of drinking, faster drinking faster absorption
stomach contents at time of drinking, alcohol absorbs slower on a full stomach
gender
weight

Question 29

dist alcohol

Answer 29

alcohol distributes quickly
present in body parts in proportion to water content
hair and bones get very little
brain gets a lot

Question 30

elimination of alc

Answer 30

metabolism, more than 90% liver
excretion in perspiration urine and breath

Question 31

alcohol in the breath

Answer 31

amount of alcohol that gets into breath is proportional to the amount of alcohol in the blood

Question 32

measuring alcohol in body

Answer 32

blood is referred method
best way to measure brain alcohol levels
whole venous blood is most commonly used
most common analysis is gas chromatography
specific easy and accurate quantitative analysis
breath alcohol is most widely used method
breathalyzer (preliminary instruments)
uses chemical oxidation
intoxilyzer (evidentiary instruments)
EC/IR
uses IR to measure alcohol

Question 33

field sobriety testing

Answer 33

series of tests administered by drug recognition expert
used to determine if there is probable cause for further testing

Question 34

three typical tests

Answer 34

horizontal gaze nystagmus
move the eyes slowly back and forth without moving head
under the influence, eyes jerk as they move
walk and turn
walk in a straight line one foot directly in front of other and turn around
eyes closed, touch finger to nose