Environmental Health Chapter 8
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Questions and Answers

What is the definition of health?

  • The absence of disease or illness
  • A state of physical but not mental well-being
  • A state of complete physical, mental, and social well-being (correct)
  • A state of mental but not physical well-being

    • What is the definition of disease?

  • A normal change in the body's condition
  • An abnormal change in the body's condition that impairs physical or psychological function (correct)
  • A normal change in the body's condition that improves physical or psychological function
  • A change in the body's condition that improves physical or psychological function

    • What factors contribute to morbidity and mortality?

  • Diet and nutrition only
  • Infectious agents only
  • Diet and nutrition, infectious agents, toxic chemicals, genetics, trauma, and psychological stress (correct)
  • Toxic chemicals only

    • What is the term for combining premature deaths and loss of healthy life resulting from illness or disability?

    <p>Disability-adjusted life years (DALYs)</p> Signup and view all the answers

    What percentage of premature deaths and diseases are accounted for by chronic conditions?

    <p>60%</p> Signup and view all the answers

    What is the predicted leading source of disability and disease worldwide by 2020?

    <p>Heart disease</p> Signup and view all the answers

    What is the predicted increase in global cancer rates?

    <p>50%</p> Signup and view all the answers

    What percentage of children born in North America today will develop diabetes in their lifetime?

    <p>One-third</p> Signup and view all the answers

    What is the main focus of conservation medicine?

    <p>Environmental changes affecting human health</p> Signup and view all the answers

    Why are pesticides becoming less effective?

    <p>Natural selection and evolution of pests</p> Signup and view all the answers

    What is a consequence of antibiotic overuse in agriculture?

    <p>The creation of antibiotic-resistant bacteria in surface waters</p> Signup and view all the answers

    Why do some antibiotic doses prescribed in the US go to waste?

    <p>Patients do not finish the full course</p> Signup and view all the answers

    What is a consequence of antibiotic resistance in hospitals?

    <p>Thousands of deaths in the US and China</p> Signup and view all the answers

    Where do most disease burdens occur?

    <p>Developing countries with limited healthcare resources</p> Signup and view all the answers

    What percentage of health care dollars are spent in developing countries?

    <p>Around 10%</p> Signup and view all the answers

    What is a threat to oak, redwoods, and Douglas fir trees in California?

    <p>An imported fungus</p> Signup and view all the answers

    What do mutagens damage or alter?

    <p>Genetic material</p> Signup and view all the answers

    What is the leading cause of death in the U.S.?

    <p>Cardiovascular disease</p> Signup and view all the answers

    What percentage of U.S. adults are considered overweight?

    <p>60%</p> Signup and view all the answers

    What determines the movement of a toxin?

    <p>Solubility</p> Signup and view all the answers

    What type of compounds move rapidly through the environment?

    <p>Water soluble compounds</p> Signup and view all the answers

    What is the primary route of exposure to toxins?

    <p>Airborne toxins</p> Signup and view all the answers

    Why are children more vulnerable to toxins?

    <p>Condition of organism and timing of exposure</p> Signup and view all the answers

    What is the consequence of fat soluble compounds in the body?

    <p>They are stored in body fat</p> Signup and view all the answers

    What is the primary site of detoxification of both natural and introduced poisons in mammals?

    <p>Liver</p> Signup and view all the answers

    Why can irritating agents be potentially carcinogenic?

    <p>Because they can cause cell division, which increases the chance of DNA mutations</p> Signup and view all the answers

    What is the purpose of animal testing in measuring toxicity?

    <p>To expose a population of laboratory animals to measured doses of specific toxins</p> Signup and view all the answers

    What is the term for the dose of a toxin that is lethal to 50% of an animal test population?

    <p>LD50</p> Signup and view all the answers

    Why are dose-response curves not symmetrical?

    <p>Because individuals have different sensitivities to toxins</p> Signup and view all the answers

    What is the amount of a moderate toxin required to produce a lethal dose?

    <p>1 g/kg of body weight</p> Signup and view all the answers

    Why is it difficult to estimate the risk of toxins to humans?

    <p>Because unrelated species react differently to toxins due to differences in physiology and metabolism</p> Signup and view all the answers

    What is the purpose of excretion in reducing the effects of waste products and environmental toxins?

    <p>To eliminate toxins from the body</p> Signup and view all the answers

    What is a common mistake people make when evaluating their abilities?

    <p>They have an exaggerated view of their abilities</p> Signup and view all the answers

    Why do people have an exaggerated fear of certain events?

    <p>Because they are reported more frequently in the news</p> Signup and view all the answers

    What is the general rule for tolerating risk according to the text?

    <p>People tolerate a high probability of an occurrence if the harm caused is low</p> Signup and view all the answers

    What is the acceptable risk of death from environmental hazards according to the EPA?

    <p>1 in 1 million</p> Signup and view all the answers

    When setting health policy, what should be considered?

    <p>The combined effects of exposure and different sensitivities</p> Signup and view all the answers

    What is a key consideration when evaluating the risks of environmental contaminants?

    <p>The effects on other organisms that maintain our environment</p> Signup and view all the answers

    Study Notes

    Environmental Health

    • Environmental health is a state of complete physical, mental, and social well-being
    • Disease is an abnormal change in the body's condition that impairs physical or psychological function
    • Factors contributing to morbidity (illness) and mortality (death) include diet and nutrition, infectious agents, toxic chemicals, genetics, trauma, and psychological stress

    Global Disease Burden

    • Life expectancy is increasing as infant mortality decreases
    • Disability-adjusted life years (DALYs) combine premature deaths and loss of healthy life resulting from illness or disability
    • Chronic conditions account for 60% of premature deaths and 50% of diseases
    • By 2020, heart disease may become the leading source of disability and disease worldwide
    • Global cancer rates will increase by 50%

    Infectious and Emergent Diseases

    • Diabetes is on the increase, with one-third of children born in North America today expected to develop diabetes in their lifetime due to poor diet and little exercise
    • Conservation medicine examines how environmental changes threaten the health of humans and natural communities
    • Examples of environmental health risks include:
      • Herpes 1 virus spreading to California sea lions from human sewage
      • An imported fungus killing oak, redwoods, and Douglas fir trees in California
      • Dermo, a parasite of oysters, spreading rapidly along the east coast due to climate warming

    Antibiotics and Pesticide Resistance

    • The protozoan parasite that causes malaria is now resistant to most antibiotics, while the mosquitoes that transmit it have developed resistance to many insecticides
    • Overuse of pesticides speeds up the process of pesticide resistance
    • Antibiotics are routinely fed to U.S. farm animals to stimulate weight gain, which creates antibiotic resistance
    • Antibiotic-resistant strains of MRSA are spreading through hospitals in the US and China, resulting in thousands of deaths

    Toxicology

    Movement, Distribution, and Fate of Toxins

    • Solubility is one of the most important characteristics in determining the movement of a toxin
    • Chemicals are divided into two major groups:
      • Those that dissolve more readily in water
      • Those that dissolve more readily in oil
    • Water-soluble compounds move rapidly through the environment and have access to cells
    • Fat-soluble compounds need a carrier to move through the environment, but once inside the body, they penetrate tissues easily and are stored in body fat, persisting for many years

    Exposure and Susceptibility

    • Airborne toxins generally cause more ill health than any other exposure
    • The lining of the lungs easily absorbs toxins
    • Food, water, and skin contact are other ways to be exposed to toxins
    • The largest toxin exposure is reported in industrial settings
    • The condition of the organism and the timing of exposure also have strong influences on toxicity
    • Children are more vulnerable than adults

    Minimizing Toxic Effects

    • Every material can be poisonous under certain conditions
    • Most chemicals have a safe threshold under which their effects are insignificant
    • Metabolic degradation is a process by which the liver breaks down toxins
    • Sometimes, compounds that are harmless can be broken down into products that are harmful

    Excretion and Repair

    • Effects of waste products and environmental toxins are reduced by eliminating via excretion (breathing, urine, etc.)
    • Tissues and organs often have mechanisms for damage repair by cellular reproduction
    • Any irritating agent can be potentially carcinogenic because the more times cells divide, the greater the chance of DNA mistakes (mutations) that can lead to cancer

    Measuring Toxicity

    • Animal testing is the most commonly used and widely accepted toxicity test
    • Humanitarian concerns arise in using animals for testing
    • Different individuals have different sensitivities to the same toxin
    • Should we aim to protect the average person or the most sensitive?

    Complications in Measuring Toxicity

    • Unrelated species can react quite differently to the same toxin due to differences in physiology and metabolism
    • Dose-response curves are not symmetrical
    • LD50 (dose at which 50% of the animal test population dies) varies between species
    • These variations make it difficult to estimate the risk to humans

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    Description

    This quiz covers environmental health and toxicology, including infectious and emergent diseases. It's based on a lecture outline by William P. Cunningham and Mary Ann Cunningham. Topics include environmental health, diseases, and toxicology.

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