10.2 Notes – Toxicology 10.2 Notes – Toxicology continuedcontinued

ObjectivesObjectives

Explain how alcohol is absorbed into the Explain how alcohol is absorbed into the bloodstream, transported throughout the bloodstream, transported throughout the body, and eliminated by oxidation and body, and eliminated by oxidation and excretion.excretion.

Understand the process by which alcohol Understand the process by which alcohol is excreted in the breath via the lungsis excreted in the breath via the lungs

Breakdown of alcohol in the Breakdown of alcohol in the bodybody

A.A. Oxidation Oxidation –– occurs in the liver using occurs in the liver using dehydrogenase to convert alcohol to dehydrogenase to convert alcohol to acetaldehyde and then to acetic acetaldehyde and then to acetic acid to carbon dioxide and wateracid to carbon dioxide and water

Breakdown of alcohol in the Breakdown of alcohol in the bodybody

A.A. rr

B.B. Excretion Excretion –– breath, urine, breath, urine, perspirationperspiration• Amount of alcohol exhaled in the Amount of alcohol exhaled in the

breath is in direct proportion to breath is in direct proportion to concentration in the bloodconcentration in the blood

Elimination rateElimination rate - .015 percent - .015 percent weight/per volume per hourweight/per volume per hour

Alcohol in the Circulatory Alcohol in the Circulatory SystemSystem

Measuring the quantity in the Measuring the quantity in the blood streamblood stream

a.a. Direct chemical analysis of the Direct chemical analysis of the bloodblood

b.b. Measurement of the alcohol Measurement of the alcohol content in the breathcontent in the breatho uses Henryuses Henry’’s Laws Law

HenryHenry’’s Laws Law

When alcohol is dissolved in blood and When alcohol is dissolved in blood and brought to equilibrium with alveolar breath, brought to equilibrium with alveolar breath, the fixed ratio between the concentration of the fixed ratio between the concentration of alcohol in alveolar air and blood is constant alcohol in alveolar air and blood is constant for a given temperature (approximately 34 for a given temperature (approximately 34 degrees C.)degrees C.)

Evidence shows alcohol in blood to alcohol Evidence shows alcohol in blood to alcohol in air 2,100 to 1: 1 mL of blood will contain in air 2,100 to 1: 1 mL of blood will contain the same amount of alcohol as 2,100 mL of the same amount of alcohol as 2,100 mL of alveolar breathalveolar breath

Circulatory SystemCirculatory System ClosedClosed Basically heart and numerous Basically heart and numerous

arteries, capillaries, and veinsarteries, capillaries, and veins Artery = blood vessel carrying blood Artery = blood vessel carrying blood

away from heartaway from heart Vein = vessel carrying blood back to Vein = vessel carrying blood back to

heartheart Capillary = tiny blood vessels that Capillary = tiny blood vessels that

interconnect the arteries and veinsinterconnect the arteries and veins

Lungs = bridges the respiratory Lungs = bridges the respiratory system to the circulatory systemsystem to the circulatory system Alveoli = tiny pear-shaped sacsAlveoli = tiny pear-shaped sacs

About 250 million in lungsAbout 250 million in lungs All located at the end of bronchial All located at the end of bronchial

tubestubes At the surface of alveolar sacs blood At the surface of alveolar sacs blood

flows and comes in contact with flows and comes in contact with oxygenated airoxygenated air

Alcohol and other substances in blood will Alcohol and other substances in blood will pass into alveolipass into alveoli

10.2 Questions – answer on 10.2 Questions – answer on notebook papernotebook paper

1. List and describe the three stages of alcohol’s fate in the human body.2. About 95-98% of alcohol is oxidized into what two substances?3. Carbon dioxide and dehydrogenase4. Water and acetic acid5. Acetaldehyde and acetic acid6. Water and carbon dioxide7. Alcohol that is not oxidized is expelled unchanged in what bodily excretions?8. The amount of alcohol exhaled in the breath is in direct proportion to what?9. From the medicolegal point of view, what is the accepted standard for relating alcohol

intake to its effects on the body?10. List and describe the functions of the three types of blood vessels in the circulatory system.11. Through the walls of which organ is most alcohol absorbed into the bloodstream? In what

other organ does the remainder of the absorption occur?12. When the blood enters the lung region from the heart, what are the relative levels of

oxygen and carbon dioxide?13. What are alveoli and what role do they play in circulation?14. What is the most widespread method for rapidly determining alcohol intoxication?15. What scientific observation forms the theoretical basis for breath testing?