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Chapter 9
Physiology of
Alcohol and
Poisons
© 2012 Cengage Learning. All Rights Reserved
Introduction—Objectives
Describe the role of a forensic toxicologist.
Discuss the legal importance of blood alcohol
levels.
3. Explain the effects of alcohol and specific drugs
and poisons on the body.
4. Discuss chemical agents that may be used for
bioterrorism.
5. Describe analytical techniques for detection and
identification of alcohol, poisons, and toxins in
bodily fluids.
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Forensic Science II: Physiology of Alcohol and Poisons, Chapter 9
© 2012 Cengage Learning. All Rights Reserved
Introduction—Vocabulary
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depressant—a chemical that slows the heart
rate and brain activity and causes
drowsiness
Immunoassay—a test that relies on the
antigen-antibody response
Nystagmus—involuntary jerking movement
of the eyes
Poison—a chemical that can harm the body
if ingested, absorbed, or breathed in
sufficiently high concentrations
Forensic Science II: Physiology of Alcohol and Poisons, Chapter 9
© 2012 Cengage Learning. All Rights Reserved
Introduction—Vocabulary
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Tolerance—in response to prolonged, heavy
intake of alcohol or other drugs, the body’s
need for progressively larger amounts of a
chemical to cause the same levels of
intoxication
Toxin—a type of poison produced naturally
by living things
Forensic Science II: Physiology of Alcohol and Poisons, Chapter 9
© 2012 Cengage Learning. All Rights Reserved
Michael Jackson
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June 25, 2009, an accidental homicide
Homicide—a person died at the hands of
another person
An overdose of medicines prescribed by
Jackson’s doctor, Conrad Murray
Coroner’s determination—the interaction of
anesthetics and sedatives caused Jackson to
stop breathing.
Forensic Science II: Physiology of Alcohol and Poisons, Chapter 9
© 2012 Cengage Learning. All Rights Reserved
History of Toxicology (Obj 9.1)
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Early 1700’s—first use of chemistry to detect
poisons
Early 19th century—toxicology became a new
scientific discipline
France in 1840—Charles Lafarge trial involved
testing for arsenic
Forensic toxicologists—study the legal and medical
aspects of alcohol, drugs, poisons, and toxins in
bodily fluids.
Forensic Science II: Physiology of Alcohol and Poisons, Chapter 9
© 2012 Cengage Learning. All Rights Reserved
Alcohol (Obj 9.2, 9.3)
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In everyday speech, alcohol usually refers to
the ethanol used in alcoholic beverages.
In chemistry, alcohols are a group of
substances with a hydroxyl group.
Forensic Science II: Physiology of Alcohol and Poisons, Chapter 9
© 2012 Cengage Learning. All Rights Reserved
Alcohol
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All alcohols are toxic in sufficient quantities
As little as 30 mL of methanol can kill
Ethanol, ethyl alcohol, is a colorless liquid
obtained from fermented grains or fruits
Initial reaction to alcohol is euphoria
Alcohol is actually a depressant
Forensic Science II: Physiology of Alcohol and Poisons, Chapter 9
© 2012 Cengage Learning. All Rights Reserved
Alcohol in the Body
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Alcohol diffuses through the stomach and
small intestines
As alcohol concentration increases:
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ability to respond to stimuli decreases
temporary euphoria results from depressing
inhibitions
lose coordination and become confused
memory diminishes
Forensic Science II: Physiology of Alcohol and Poisons, Chapter 9
© 2012 Cengage Learning. All Rights Reserved
Alcohol in the Body
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The liver metabolizes alcohol with an
enzyme called alcohol dehydrogenase (ADH)
Resulting product is acetaldehyde
More enzymes break this into CO2 and H2O
The body can metabolize 15 to 30 mL of
alcohol per hour
Excess alcohol is distributed to body tissues
Forensic Science II: Physiology of Alcohol and Poisons, Chapter 9
© 2012 Cengage Learning. All Rights Reserved
Stages of Intoxication
A blood alcohol concentration of 0.08 means
8 g of alcohol
per 10,000 mL
of blood
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Forensic Science II: Physiology of Alcohol and Poisons, Chapter 9
© 2012 Cengage Learning. All Rights Reserved
Stages of Intoxication
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Alcohol affects different people differently
Concentration
Behavior
0.01 to 0.05
Normal behavior
0.03 to 0.12
Euphoria begins
0.09 to 0.25
Vision blurs, loss of balance,
sleepiness
Speech slurs, dizzy, disoriented,
emotional
0.18 to 0.30
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Forensic Science II: Physiology of Alcohol and Poisons, Chapter 9
© 2012 Cengage Learning. All Rights Reserved
Stages of Intoxication (cont.)
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Alcohol affects different people differently
Concentration
Behavior
0.25 to 0.40
Standing and walking is difficult
0.35 to 0.50
Impaired respiratory and circulatory
systems
Potentially fatal
Over 0.45
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Forensic Science II: Physiology of Alcohol and Poisons, Chapter 9
© 2012 Cengage Learning. All Rights Reserved
Stages of Intoxication
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Factors affecting alcohol absorption
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Body weight
How much alcohol is consumed
Over what time period
Amount of food in the stomach
Frequency of drinking alcohol
Body fat percentage
Medications and popular energy drinks
Forensic Science II: Physiology of Alcohol and Poisons, Chapter 9
© 2012 Cengage Learning. All Rights Reserved
Stages of Intoxication
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Forensic Science II: Physiology of Alcohol and Poisons, Chapter 9
© 2012 Cengage Learning. All Rights Reserved
Tolerance
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Metabolic tolerance—the body produces
larger amounts of alcohol dehydrogenase
Functional tolerance—a person displays
fewer visible symptoms of intoxication
without affecting blood alcohol concentration
Forensic Science II: Physiology of Alcohol and Poisons, Chapter 9
© 2012 Cengage Learning. All Rights Reserved
Field Sobriety Tests
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Horizontal gaze nystagmus (HGN) test
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Divided-attention tests
Breath tests
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Nystagmus is the involuntary jerking of human
eyes, which increases with intoxication
Direct correlation between
alcohol in the breath and
alcohol in the blood stream
Ratio is 1:2100
Forensic Science II: Physiology of Alcohol and Poisons, Chapter 9
© 2012 Cengage Learning. All Rights Reserved
Blood and Urine Tests
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Toxicology labs use gas chromatography/
mass spectrometry (GC/MS)
Gas chromatography separates the sample
into individual components
Forensic Science II: Physiology of Alcohol and Poisons, Chapter 9
© 2012 Cengage Learning. All Rights Reserved
Act of 1984
Prior to 1984, the legal drinking age varied
from state to state. In some states, the age
was set as low as age 18. The National
Minimum Drinking Age Act of 1984, also
called the Uniform Drinking Age Act,
mandated that no one under the age of 21 be
allowed to purchase alcohol within the United
States.
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Forensic Science II: Physiology of Alcohol and Poisons, Chapter 9
© 2012 Cengage Learning. All Rights Reserved
Blood Alcohol Calculation
Calculation of Blood Alcohol Concentration (BAC)
The Research by Widmark, a Swedish physician, is 100 years old and his formula is listed below. I have found doing this
calculation to be rewarding in that it gives you a sense of how much you can drink before you test above the
allowable. You should note that doing this computation is only a guide and the results are not 100% accurate.
Factors too numerous to mention and not brought into play. Experiment!
Widmark’s Basic Formula for calculating BAC (Blood Alcohol Concentration) at a particular time is expressed as follows:
%BAC = (A x 5.14/W x r) – .015 x H
“A” is the total number of liquid ounces of alcohol consumed by the person since the commencement of drinking. This
figure is ascertained by multiplying the number of liquid ounces of alcoholic beverages consumed by the percentage
of alcohol in the beverage. For example, a typical bottle of regular beer contains .60 liquid ounces of alcohol (12 oz.
X 5%). A typical glass of table wine contains .60 liquid ounces of alcohol (5 oz. X 12%). And, most hard liquors
contain 40 per cent alcohol by volume with a typical size of drink being 1.25 ounces and so a typical shot of hard
liquor contains .50 ounces of alcohol (1.25 oz x 40%).
The 5.14 in the formula is a conversion factor of .823 x 100/16, wherein .823 is used to convert liquid ounces to ounces of
weight, 100 is used to convert the final figure to a percentage, and 16 is used to convert pounds to ounces.
The 0.15 figure appearing in the formula is the average alcohol elimination rate.
“W” is for weight of the person in pounds
“r” in the alcohol distribution ratio which for men is .73 and for women is .66.
“H” is the period in hours during which alcohol was eliminated from the bloodstream and this is usually the total number of
hours between commencement of drinking and the time the BAC calculation is made.
Note: This is a very well-known formula. Widmark is very famous in this area of work. The formula is not full proof but only
a guide.
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Forensic Science II: Physiology of Alcohol and Poisons, Chapter 9
© 2012 Cengage Learning. All Rights Reserved
Poisons (Obj 9.3, 9.4)
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Eaten (ingested)
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Inhaled
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90% - at home, involving
children
household cleaners
carbon monoxide
sarin, a nerve gas
Forensic Science II: Physiology of Alcohol and Poisons, Chapter 9
© 2012 Cengage Learning. All Rights Reserved
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Injected
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heroin
Absorbed
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Poison sumac, mustard
gas, ricin, anthrax
Drugs
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Forensic Science II: Physiology of Alcohol and Poisons, Chapter 9
© 2012 Cengage Learning. All Rights Reserved
Toxicological Testing (Obj 9.5)
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Detect trace amounts of drugs in the blood,
urine, and body tissues with
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thin layer chromatography,
gas chromatography, and
immunoassay techniques
Confirmation is achieved
using GC/MS.
Forensic Science II: Physiology of Alcohol and Poisons, Chapter 9
© 2012 Cengage Learning. All Rights Reserved
Toxicological Testing
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Reinsch test—for heavy metal poisoning
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Certain metals dipped in hydrochloric acid
produce a silver-colored coating on copper
Emission spectroscopy or atomic absorption
spectrophotometry—identifies the specific
metal
Blood gas screenings—detects level of CO in
the blood stream
Forensic Science II: Physiology of Alcohol and Poisons, Chapter 9
© 2012 Cengage Learning. All Rights Reserved
Toxicological Testing
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Immunoassay—measures the level of
antibodies produced in response to antigens
(poisons) entering the bloodstream
EMIT—enzyme-multiplied immunoassay
technique
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Rapidly detects several drugs and their
metabolites
Forensic Science II: Physiology of Alcohol and Poisons, Chapter 9
© 2012 Cengage Learning. All Rights Reserved
Chapter Summary
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Poisons are chemicals that harm the body if
ingested, inhaled, or absorbed through the
skin.
Forensic toxicologists investigate the legal
and medical aspects of alcohol, drugs,
poisons, and toxins in the body; also
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testifying as expert witnesses,
collaborating with the medical examiner, and
analyzing evidence.
Forensic Science II: Physiology of Alcohol and Poisons, Chapter 9
© 2012 Cengage Learning. All Rights Reserved
Chapter Summary
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The role of forensic toxicologist also
includes:
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testing employees for drug use,
screening athletes for drug use, and
testing sexual assault victims for the presence of
date rape drugs.
In everyday speech, alcohol usually refers to
the ethanol used in alcoholic beverages.
In chemistry, alcohols are a group of
substances with a hydroxyl group.
Forensic Science II: Physiology of Alcohol and Poisons, Chapter 9
© 2012 Cengage Learning. All Rights Reserved
Chapter Summary
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Alcohol is a depressant.
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Initially, it causes feelings of euphoria.
When more is consumed,
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motor skills become impaired,
brain function is depressed, and
the person may even lapse into a coma and die.
The liver can metabolize about 15 to 30 mL
of alcohol per hour. A person becomes
intoxicated when consumption exceeds that.
Forensic Science II: Physiology of Alcohol and Poisons, Chapter 9
© 2012 Cengage Learning. All Rights Reserved
Chapter Summary
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When a driver is suspected of intoxication,
several field sobriety tests are given
Presumptive tests
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Conclusive test
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horizontal gaze nystagmus and
divided-attention tests
breath tests can determine blood alcohol levels.
Forensic Science II: Physiology of Alcohol and Poisons, Chapter 9
© 2012 Cengage Learning. All Rights Reserved
Chapter Summary
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How the poison enters the body determines its effect
on the body
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Testing procedures
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inhaled poisons can cause asphyxia
ingested poisons often target specific organs
Chromatography techniques, mass spectrometry, and
immunoassay are used to detect various poisons and drugs
in urine and blood
Reinsch test detects heavy-metal poisoning
Forensic Science II: Physiology of Alcohol and Poisons, Chapter 9
© 2012 Cengage Learning. All Rights Reserved