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Questions and Answers
What does NOAEL stand for in toxicity assessment?
What does NOAEL stand for in toxicity assessment?
What is indicated by a substance classified as a non-threshold toxicant?
What is indicated by a substance classified as a non-threshold toxicant?
What does LOAEL stand for in the context of toxicity?
What does LOAEL stand for in the context of toxicity?
Which of the following substances is an example of a non-threshold toxicant?
Which of the following substances is an example of a non-threshold toxicant?
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What determines safe exposure levels for toxic substances?
What determines safe exposure levels for toxic substances?
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What is environmental toxicology primarily concerned with?
What is environmental toxicology primarily concerned with?
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Which of the following is NOT a phase of toxicokinetics?
Which of the following is NOT a phase of toxicokinetics?
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What defines a xenobiotic?
What defines a xenobiotic?
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Which of the following processes describes the entry of toxicants into the body?
Which of the following processes describes the entry of toxicants into the body?
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What aspect does toxicodynamics cover?
What aspect does toxicodynamics cover?
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Which of the following substances can be classified as a xenobiotic?
Which of the following substances can be classified as a xenobiotic?
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Which organ is primarily involved in the metabolism of toxicants?
Which organ is primarily involved in the metabolism of toxicants?
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What is the main goal of toxicology?
What is the main goal of toxicology?
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Which of the following types of toxicity is NOT listed as a typical organ- or tissue-specific toxicity?
Which of the following types of toxicity is NOT listed as a typical organ- or tissue-specific toxicity?
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What is the primary factor that influences the severity of toxic responses?
What is the primary factor that influences the severity of toxic responses?
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Chronic toxicity can result from which of the following conditions?
Chronic toxicity can result from which of the following conditions?
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Which mechanism of toxicity is primarily associated with harmful effects on genetic material?
Which mechanism of toxicity is primarily associated with harmful effects on genetic material?
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According to Haber’s Law, what happens as the duration of exposure to a toxicant increases?
According to Haber’s Law, what happens as the duration of exposure to a toxicant increases?
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In what scenario does subacute exposure typically occur?
In what scenario does subacute exposure typically occur?
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Which factor is considered when assessing external doses of toxicants?
Which factor is considered when assessing external doses of toxicants?
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What process is used to estimate past exposures to toxicants?
What process is used to estimate past exposures to toxicants?
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Which of the following is a common approach to quantify dose?
Which of the following is a common approach to quantify dose?
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What is a characteristic of acute toxicity?
What is a characteristic of acute toxicity?
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Which of the following is considered a blood sample measurement for internal dose assessment?
Which of the following is considered a blood sample measurement for internal dose assessment?
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Which of the following routes would be considered when evaluating the distribution of a toxicant?
Which of the following routes would be considered when evaluating the distribution of a toxicant?
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What does the term 'susceptibility' refer to in the context of toxicant exposure?
What does the term 'susceptibility' refer to in the context of toxicant exposure?
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What notorious effect did thalidomide have when introduced as a medication?
What notorious effect did thalidomide have when introduced as a medication?
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Which factor does NOT influence individual susceptibility to toxicant effects?
Which factor does NOT influence individual susceptibility to toxicant effects?
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What does the study of toxicology primarily focus on?
What does the study of toxicology primarily focus on?
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What constitutes a comprehensive assessment of all sources of exposure to a toxicant?
What constitutes a comprehensive assessment of all sources of exposure to a toxicant?
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Which of the following statements about intrinsic toxicity is true?
Which of the following statements about intrinsic toxicity is true?
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Which factor is NOT one of the primary determinants of adverse effects in toxicology?
Which factor is NOT one of the primary determinants of adverse effects in toxicology?
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What does the term 'threshold' refer to in toxicology?
What does the term 'threshold' refer to in toxicology?
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Who is known as the 'father of toxicology'?
Who is known as the 'father of toxicology'?
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Which of the following was historically used by the Greeks as a state poison?
Which of the following was historically used by the Greeks as a state poison?
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What does the phrase 'Dose makes the poison' imply?
What does the phrase 'Dose makes the poison' imply?
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Approximately how many new chemicals enter the market each year?
Approximately how many new chemicals enter the market each year?
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Study Notes
Introduction to Toxicology and Environmental Health
- Environmental toxicology studies harmful effects of chemicals, biological, and physical agents on living organisms in ecosystems, including humans.
- It connects toxicology, environmental health, and public policy, describing chemical transport, fate, persistence, and bioaccumulation.
- It analyzes effects on populations and communities.
Causes of Death
- Chronic obstructive pulmonary disease (lung)
- Asthma
- Cardiovascular disease
- Cancer
- Congenital diseases
Xenobiotics, Exposure, Toxicokinetics, and Toxicodynamics
- Xenobiotic: a substance foreign to the body or ecosystem.
- Exposure: how a xenobiotic comes into contact with the body.
- Toxicokinetics: describes what happens to a xenobiotic in the body (absorption, distribution, metabolism, and elimination).
- Toxicodynamics: describes the effect of the xenobiotic on the body.
Absorption
- Entry of toxicants through external barriers (skin, lungs, gastrointestinal tract) into the circulatory system.
Distribution
- Movement of toxicants through circulatory fluids to organs and tissues (blood plasma, tissues).
Metabolism/Biotransformation
- Biochemical processes converting original toxicant to metabolites.
Excretion/Elimination
- Removal of toxicant or its metabolites from the body (kidneys, liver, lungs, saliva, sweat, breast milk).
Toxicology
- Study of poisons.
- Provides information to assess potential health risks from chemical exposures.
- Examines adverse effects on living organisms and ecosystems.
- Addresses harmful effects of drugs, environmental contaminants, and naturally occurring substances.
- Analyzes effects on biological systems, including humans, animals, and ecosystems.
- Involves identification, analysis, effects, and treatment of poisons.
History of Toxicology
- Approximately 100,000 chemicals currently in use worldwide.
- 500 new chemicals enter the marketplace annually.
- Examples of historical use include hemlock (Greeks), arsenic (Romans), opium (Chinese), and curare.
- Paracelsus: "Dose makes the poison"
- Mathieu Orfila: "father of toxicology"
Primary Factors Influencing Toxicity
- Intrinsic toxicity: harmful effects of a substance on living organisms, regardless of amount or exposure. Affected by chemical properties (molecular structure, solubility, stability, reactivity, volatility), and chemical species.
- Dose: Amount of substance.
- Exposure conditions: how the substance enters the body.
- Individual susceptibility: differences in how individuals respond to toxicants. Factors include sex, age, nutrition, medical history, genetic background, and environmental exposures.
Acute and Chronic Toxicity
- Acute toxicity: effects observed within 24 hours, typically from a single exposure.
- Subchronic toxicity: repeated exposure for one to three months.
- Chronic toxicity: repeated exposure over a period longer than three months, potentially a lifetime.
- Haber's Law: It takes less of a toxicant to cause an adverse effect as exposure duration increases.
Dose-Response Relationships
- Dose: amount of substance an organism ingests.
- Response: the adverse effects.
- NOAEL: No observed adverse effect level (highest dose showing no adverse effects).
- LOAEL: Lowest observed adverse effect level.
- Dose-response relationships explain how the intensity of a toxic effect depends on the dose or exposure amount.
Susceptibility Factors
- Susceptibility to toxicants differs among individuals based on various factors.
- Population dose-response relationships show variability in responses among different groups with respect to a given dose.
Toxic Effects
- Effects are categorized by location (target organ) and mechanisms of action.
- Toxicants can have multiple target organs.
- Mechanisms of toxicity include blood effects, skin effects, eye and cellular effects, immunotoxicity, and many more.
- Time factors: acute, subacute, chronic.
- Exposures: in utero, chronic.
Measuring Dose
- External dose: amount of toxicant ingested, breathed,or absorbed through skin.
- Internal dose: amount of toxicant absorbed into the body.
- Techniques include measuring toxicant concentrations in various bodily fluids, samples, or tissue.
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Description
This quiz covers key concepts in environmental toxicology, including the harmful effects of chemicals and biological agents on ecosystems and human health. It also discusses important topics such as xenobiotics, their exposure pathways, and the processes of toxicokinetics and toxicodynamics. Test your knowledge on how these factors relate to public policy and chronic diseases.
