42 Questions
What is the primary focus of the discipline of toxicology?
The recognition of poisonous substances in living systems
What is the term for a man-made substance or a substance produced by a living organism but not normally found in the body?
Xenobiotic
Where do most poisonings occur?
At home
Which of the following household products is commonly implicated in poisonings?
Cleaning solutions
What is the term for the poisonous chemical or agent that can cause harm to living systems?
Toxicant
Who is credited with being the 'father of modern toxicology'?
Paracelsus
What is the name of the alkaloid that caused Socrates' death?
Coniine
What is the famous quote from Paracelsus that relates to toxicology?
All substances are poisons: there is none which is not a poison
What is the primary concern when a drug is administered beyond its therapeutic dose?
The toxic effects of the drug
What is the term for the dose of a substance at which no observable effects occur?
NOEL (no observable effect level)
Which of the following is an example of a sensitive sub-population?
Pregnant women
What is the primary role of toxicologists in the FDA?
To develop regulations for medications and food additives
What type of toxicology is concerned with understanding the mechanisms of toxicity?
Mechanistic toxicology
What is the primary goal of descriptive toxicology?
To provide information for safety evaluation and regulatory requirements
What is the term for the study of the amount of a toxin present in a sample?
Analytical toxicology
Which of the following organizations is responsible for setting allowable workplace exposure limits?
OSHA
Which branch of toxicology deals with the detection and identification of foreign compounds in biological and related specimens?
Analytical Toxicology
What is the primary focus of Environmental Toxicology?
Integrating toxicology with ecology and environmental chemistry
Which branch of toxicology is concerned with making the work environment safe and protecting workers from toxic substances?
Occupational (Industrial) Toxicology
What is the estimated number of deaths caused by occupational diseases due to industrial chemicals in the US each year?
50,000 to 70,000
Which branch of toxicology deals with the effects of toxic substances on humans and the diagnosis and treatment of poisoned patients?
Clinical Toxicology
What is the primary goal of Mechanistic Toxicology?
To understand the cellular, biochemical, and molecular basis of toxic substances
Which branch of toxicology deals with the regulation of toxic substances and the establishment of safety guidelines?
Regulatory Toxicology
What is the focus of Forensic Toxicology?
Analysing toxic substances in biological specimens for legal purposes
What type of exposure is often associated with acute toxicity?
One large exposure
Which of the following is an example of systemic toxicity?
Lead ingestion leading to neurological effects
What is the primary route of entry for a toxic substance that causes acute inhalation toxicity?
Inhalation
What is the term used to describe the relationship between a toxic substance, the environment, and the host?
Toxic triangle
What is the primary characteristic of chronic toxicity?
Delayed effects with a latency period
Which of the following is an example of local toxicity?
Acid burning the skin
What is the term used to describe the absorption of a toxic substance through the skin?
Dermal absorption
Which of the following is NOT a characteristic of the 'host' in the toxic triangle?
Chemical properties of the toxic substance
What is the approximate lethal dose of sugar for a 160 lb human?
3 quarts
How many teaspoons of arsenic would be fatal to a human?
1-2 teaspoons
What is the effect of two chemicals with synergistic interactions?
The combined effect is much greater than the sum of the effects of each chemical
Why is chronic use of aspirin deleterious to the gastric mucosa?
Because it affects the gastric mucosa over time
What is the approximate lethal dose of herbicide (2,4-D) for a 160 lb human?
one half cup
What is the term for the combined effect of two chemicals equal to the sum of the effects of each chemical acting independently?
Addition
Why is vinyl chloride considered a toxic substance?
Because it is a carcinogen at very low doses
What is the approximate lethal dose of nicotine for a 160 lb human?
1/2 teaspoon
What is the effect of two chemicals with additive interactions?
The combined effect is equal to the sum of the effects of each chemical
Why is chronic use of metals, such as iron, copper, magnesium, cobalt, and zinc, not toxic to humans?
Because they are dietary essentials
Study Notes
Toxicology Basics
- Beyond therapeutic dose, a drug can be toxic, and only the toxic effects are of concern.
- At low doses, there may be no effect (NOEL – no observable effect level), while at levels greater than NOEL, toxicity occurs.
- Individual susceptibility refers to the differences between people, making some more at risk for certain health conditions than others.
- Sensitive sub-populations are more at risk from illness due to exposure than the average healthy person.
Roles of Toxicologists
- Test animals to determine the risk from a particular chemical or agent.
- Study the mechanism of a toxin to determine if or how animal studies may be related to humans.
- Take data and develop regulations for agencies like FDA, EPA, and OSHA.
Classifications of Toxicology
- Descriptive Toxicology: the science of toxicity testing, especially from animal experimentation, to provide information for safety evaluation and regulatory requirements.
- Mechanistic Toxicology: makes observations on how toxic substances cause their effects by identifying and understanding the cellular, biochemical, and molecular basis.
- Analytical Toxicology: the detection, identification, and measurement of foreign compounds (xenobiotics) in biological and related specimens.
Sub-Disciplines of Toxicology
- Applied Toxicology
- Environmental Toxicology: integrates toxicology with sub-disciplines like ecology, wildlife, and aquatic biology, and environmental chemistry.
- Occupational (Industrial) Toxicology: combines occupational medicine and occupational hygiene to protect workers from toxic substances.
- Regulatory Toxicology
- Food Toxicology
- Clinical Toxicology
- Forensic Toxicology
Toxicology Concepts
- Lethal Doses: approximate lethal doses of common chemicals, calculated for a 160 lb human from data on rats.
- Interactions between chemicals: addition (1 + 1 = 2) and synergism (1 + 1 = 5) can affect the outcome of toxicant exposure.
- Xenobiotic: a man-made substance and/or produced by but not normally found in the body.
- Toxicant: a specific poisonous chemical/agent.
- Foreign substances: household products, plants, and certain animals can be poisonous to humans and animals.
History of Toxicology
- 399 BC: death of Socrates by Hemlock
- 1493-1541: Swiss physician Paracelsus, credited with being "the father of modern toxicology"
- 17th century: Romeo and Juliet's reference to poisoning
Types of Toxicity
- Acute: short-term exposure, often one large exposure, immediate damage, and reversible damage.
- Chronic: exposure over a long period, usually small exposures, delayed effects, and irreversible damage.
- Local Toxicity: occurs at the site of application or exposure.
- Systemic Toxicity: requires absorption of the toxicant by the body and distribution via the bloodstream to target organ(s).
Routes of Exposure
- Inhalation: most direct and rapid entrance into the body
- Dermal/Absorption: chemical transfer from the surface of the skin into the body
- Ingestion: poor hygiene or accident
- Puncture/Injection: minimal hazard in most industries
The Toxic Triangle
- Environment: the setting where the toxic substance interacts with humans and the environment.
- Hazard: the characteristics of the toxic substance.
- Host: the characteristics of the human or organism affected by the toxic substance.
Test your knowledge of toxicology, the study of the adverse effects of toxic agents on living systems. Learn about the different types of toxic agents, including xenobiotics and toxicants, and how they affect the body. Discover the most common household products that can cause poisoning.
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