1. 10.2 Notes – Toxicology continued

2. 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

3. Breakdown of alcohol in the body
Oxidation – occurs in the liver using dehydrogenase to convert alcohol to acetaldehyde and then to acetic acid to carbon dioxide and water

4. Breakdown of alcohol in the body
Excretion – breath, urine, perspiration
Amount of alcohol exhaled in the breath is in direct proportion to concentration in the blood
Elimination rate percent weight/per volume per hour

5. Alcohol in the Circulatory System
Measuring the quantity in the blood stream
Direct chemical analysis of the blood
Measurement of the alcohol content in the breath
uses Henry’s Law

6. Henry’s Law
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

7. Circulatory System Closed
Basically heart and numerous arteries, capillaries, and veins
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

8. 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

9. 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?
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?
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?