Transcript alcohol

Alcohol & Poisons
• 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
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History of Toxicology (Obj 9.1)
• Early 1700’s—first use of chemistry to detect
poisons
• Early 19th century—toxicology became a new
scientific discipline
Forensic Science II: Physiology of Alcohol and Poisons,
Chapter 9
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France in 1840—Charles Lafarge trial
involved testing for arsenic
• Charles Lafarge became ill and
died.
• His wife Marie was accused of
killing him with rat poison.
• Yrs earlier, chemist, James Marsh,
developed a test to detect arsenic,
the major ingredient in rat poison.
• The Marsh test helped
investigators find traces of arsenic
in food at the Lafarge home, but
were not able to detect the poison
in Lafarge’s body.
Forensic Science II: Physiology of Alcohol and Poisons,
Chapter 9
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• The leading authority in
medical toxicology at that
time, Mathieu Orfila, was
called in to retest Lafarge’s
exhumed body.
• Orfila found traces of arsenic in
Lafarge’s body.
• The soil surrounding the body
was also tested and no traces
of arsenic were found,
disproving claims by the
defense that poison had been
absorbed into the body after
burial.
• Marie Lafarge was convicted
of murder.
Forensic Science II: Physiology of Alcohol and Poisons,
Chapter 9
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• Forensic toxicologists—
study the legal and medical
aspects of alcohol, drugs,
poisons, and toxins in
bodily fluids.
• Toxicologists and
pathologists work together
because many autopsies
involve analysis of body
fluids and tissues for the
detection of poisons or
drugs.
Forensic Science II: Physiology of Alcohol and Poisons,
Chapter 9
© 2012 Cengage Learning. All Rights Reserved
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Alcohol (Obj 9.2, 9.3)
• In everyday speech, alcohol usually refers to the
ethanol used in alcoholic beverages (beer, wine, or
liquor.)
• In chemistry, alcohols are a group of substances
with a hydroxyl (–OH) group.
Forensic Science II: Physiology of Alcohol and Poisons,
Chapter 9
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Alcohol
• Some alcohols are used as solvents
and can be found in antifreeze,
perfumes, fuels, hairspray, and
medications.
• All alcohols are toxic in sufficient
quantities
• As little as 30 mL of methanol can
kill
• When ingested, propanol, or
rubbing alcohol, causes decreased
heart rate, dizziness, and internal
hemorrhage.
• Ethanol, the alcohol in alcoholic
beverages, can be fatal if consumed
in large quantities.
Forensic Science II: Physiology of Alcohol and Poisons,
Chapter 9
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Alcohol in the Body
• Ethanol (ethyl alcohol)-colorless liquid obtained
from fermented grains or fruits
• Initial reaction-euphoria but alcohol is actually a
depressant (a chemical that slows the heart rate
and brain activity and causes drowsiness)
Forensic Science II: Physiology of Alcohol and Poisons,
Chapter 9
© 2012 Cengage Learning. All Rights Reserved
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Absorption of alcohol in the body begins
when it:
Diffuses through the stomach and
small intestine into the
bloodstream
• 1st, the person feels less
inhibited, happy and talkative
(the part of the brain that
controls inhibitions is depressed)
• As more alcohol is absorbed, the
person begins to lose
coordination and to become
confused (the part of the brain
responsible for learning and
memory becomes affected)
Forensic Science II: Physiology of Alcohol and Poisons,
Chapter 9
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Alcohol in the Body
• In the liver, alcohol is metabolized, or broken down, by the enzyme
alcohol dehydrogenase (ADH).
• The resulting product is acetaldehyde.
• The acetaldehyde is broken down into carbon dioxide and water.
• The liver can normally metabolize one or two alcoholic drinks (15 to
30 mL/hr).
• 90% of the ingested alcohol is converted to carbon dioxide and
water.
• 10% is excreted from the body in the breath, perspiration, and
urine.
• When a person drinks more alcohol than the liver can metabolize,
the excess alcohol is distributed to the tissues of the body.
Forensic Science II: Physiology of Alcohol and Poisons,
Chapter 9
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BLOOD ALCOHOL CONCENTRATIONS AND
STAGES OF INTOXICATION
• Determining the amount
of alcohol in a person’s
blood is a good indication
of the level of intoxication
the person is
experiencing.
• A blood alcohol
concentration (BAC) of
0.08 means there are 8 g
of alcohol to every 10,000
mL of blood or 0.08g of
alcohol for every 100mlof
blood.
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Stages of Intoxication
• Alcohol affects different people differently
Concentration
Behavior
0.01 to 0.05
Normal behavior
0.03 to 0.12
euphoria, talkative, less inhibited, more
confident, loss of motor skills
0.09 to 0.25
blurred vision, loss of balance &
coordination, sleepiness.
0.18 to 0.30
slurred speech, dizziness &
disorientation, emotional & confusion,
increased tolerance for pain & respiratory
system may be affected.
Forensic Science II: Physiology of Alcohol and Poisons,
Chapter 9
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Stages of Intoxication (cont.)
• Alcohol affects different people differently
Concentration
Behavior
0.25 to 0.40
standing and walking is very difficult;
vomiting, loss of bladder control.
0.35 to 0.50
impaired respiratory & circulatory
systems, difficulty breathing, drop in
body temperature, coma & possibly
death.
Over 0.45
Potentially fatal due to respiratory
arrest.
Forensic Science II: Physiology of Alcohol and Poisons,
Chapter 9
© 2012 Cengage Learning. All Rights Reserved
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