Transcript revised 10.2 notes - Trimble County Schools

10.2 Notes – Toxicology
continued
Objectives


Explain how alcohol is absorbed into the
bloodstream, transported throughout the body,
and eliminated by oxidation and excretion.
Understand the process by which alcohol is
excreted in the breath via the lungs
Breakdown of alcohol in the body
A.
Oxidation – occurs in the liver using
dehydrogenase to convert alcohol to
acetaldehyde and then to acetic acid to
carbon dioxide and water
Breakdown of alcohol in the body
A.
r
B.
Excretion – breath, urine, perspiration
•

Amount of alcohol exhaled in the breath is in
direct proportion to concentration in the
blood
Elimination rate - .015 percent
weight/per volume per hour
Alcohol in the Circulatory System

Measuring the quantity in the blood
stream
a.
b.
Direct chemical analysis of the blood
Measurement of the alcohol content in
the breath
o
uses Henry’s Law
Henry’s Law
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
When alcohol is dissolved in blood and brought
to equilibrium with alveolar breath, the fixed
ratio between the concentration of alcohol in
alveolar air and blood is constant for a given
temperature (approximately 34 degrees C.)
Evidence shows alcohol in blood to alcohol in air
2,100 to 1: 1 mL of blood will contain the same
amount of alcohol as 2,100 mL of alveolar
breath
Circulatory System


Closed
Basically heart and numerous arteries,
capillaries, and veins
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Artery = blood vessel carrying blood away
from heart
Vein = vessel carrying blood back to heart
Capillary = tiny blood vessels that
interconnect the arteries and veins

Lungs = bridges the respiratory
system to the circulatory system

Alveoli = tiny pear-shaped sacs
 About
250 million in lungs
 All located at the end of bronchial tubes
 At the surface of alveolar sacs blood flows
and comes in contact with oxygenated air

Alcohol and other substances in blood will pass
into alveoli
10.2 Questions – answer on
notebook paper
List and describe the three stages of alcohol’s fate in the human
body.
About 95-98% of alcohol is oxidized into what two substances?
1.
2.
A.
B.
C.
D.
3.
4.
5.
Carbon dioxide and dehydrogenase
Water and acetic acid
Acetaldehyde and acetic acid
Water and carbon dioxide
Alcohol that is not oxidized is expelled unchanged in what bodily
excretions?
The amount of alcohol exhaled in the breath is in direct proportion
to what?
From the medicolegal point of view, what is the accepted standard
for relating alcohol intake to its effects on the body?
10.2 Questions – cont
6.
7.
8.
9.
10.
11.
List and describe the functions of the three types of blood vessels
in the circulatory system.
Through the walls of which organ is most alcohol absorbed into
the bloodstream? In what other organ does the remainder of the
absorption occur?
When the blood enters the lung region from the heart, what are
the relative levels of oxygen and carbon dioxide?
What are alveoli and what role do they play in circulation?
What is the most widespread method for rapidly determining
alcohol intoxication?
What scientific observation forms the theoretical basis for breath
testing?