Toxic Gases: Classification and Routes of Exposure

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Questions and Answers

What is the main function of the lower respiratory tract?

Gas exchange (correct)

Deep inhalation

Ventilation

Oral ingestion

Which classification of toxic gases includes chemicals that induce cellular hypoxia or anoxia?

Chemical asphyxiants (correct)

Pulmonary irritants

Toxic products of combustion

Simple asphyxiants

Which toxic gas is odorless, colorless, and nonirritating, and is labeled as the silent killer?

Carbon Monoxide (correct)

Cyanide

Hydrogen Sulfide

Lacrimating agents

What are the routes of exposure to toxic gases?

Oral ingestion and local dermal contact Signup and view all the answers

Which part of the respiratory system consists of the trachea, bronchi, bronchioles, and lungs?

Lower respiratory tract (LRT) Signup and view all the answers

What do chemical asphyxiants frequently interfere with to produce toxicity?

Normal physiologic respiration Signup and view all the answers

What is the normal range for adult blood CO levels?

0.40% - 0.55% Signup and view all the answers

Which gas is a major source of CO in tobacco smoke?

Carbon monoxide Signup and view all the answers

What is the mechanism of CO toxicity?

It impairs electron transport chain Signup and view all the answers

What is the estimated strength of the binding of CO to ferrous ion (Fe+2) in Hb compared to molecular O2?

200-250 times stronger Signup and view all the answers

What is the formula used to estimate the degree of binding of CO to Hb?

%COHb = RMV × [CO] × time Signup and view all the answers

What COHb levels are considered potentially harmful in nonsmokers and smokers?

5% or more in nonsmokers, 10% or more in smokers Signup and view all the answers

What is the approximate half life of COHb?

4-5 hours Signup and view all the answers

What are the symptoms of acute, mild exposure to CO?

Headache, dizziness, malaise, and fatigue Signup and view all the answers

Which substance is metabolized by hepatic mixed function oxidases to CO and CO2?

$C_2H_2Cl_2$ (methylene chloride) Signup and view all the answers

Which gas is NOT a source of carbon monoxide as mentioned in the text?

$CO_2$ (carbon dioxide) Signup and view all the answers

Study Notes

Lower Respiratory Tract

The main function of the lower respiratory tract is to facilitate gas exchange.

Toxic Gases

Chemicals that induce cellular hypoxia or anoxia are classified as chemical asphyxiants.
Carbon monoxide (CO) is an odorless, colorless, and nonirritating gas, labeled as the silent killer.

Routes of Exposure

Toxic gases can enter the body through inhalation, ingestion, or skin absorption.

Respiratory System

The lower respiratory system consists of the trachea, bronchi, bronchioles, and lungs.

Chemical Asphyxiants

Chemical asphyxiants frequently interfere with cellular respiration to produce toxicity.

Blood CO Levels

The normal range for adult blood CO levels is not specified in the text.

Tobacco Smoke

Tobacco smoke is a major source of CO.

CO Toxicity

The mechanism of CO toxicity involves the binding of CO to ferrous ion (Fe+2) in hemoglobin (Hb).
CO binds to Hb with an estimated strength 210-240 times greater than molecular O2.

COHb Formula

The formula used to estimate the degree of binding of CO to Hb is not specified in the text.

COHb Levels

COHb levels above 10% are considered potentially harmful in nonsmokers, and above 15% in smokers.

COHb Half-Life

The approximate half-life of COHb is not specified in the text.

Acute CO Exposure

Symptoms of acute, mild exposure to CO include headaches, dizziness, and nausea.

Metabolism

Methanol is metabolized by hepatic mixed function oxidases to CO and CO2.

CO Sources

Cigarette smoke, automobile exhaust, and faulty furnaces are sources of CO; methane is NOT a source of CO.

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Description

Learn about the classification of toxic gases into chemical asphyxiants, pulmonary irritants, simple asphyxiants, toxic products of combustion, and lacrimating agents. Explore the routes of exposure including oral ingestion and local dermal or mucous membrane contact. Understand the composition of the respiratory system, including the upper and lower respiratory tracts.