Problem 1: Natural and human-made chemicals

Which statement is the most correct?

A. Chemicals manufactured by humans are more dangerous to human health than naturally occurring chemicals.

B. Both natural and human-made chemicals are potentially toxic to humans.

All chemicals, whether natural or synthetic, have the potential to be hazardous to humans. The likelihood of harm to humans depends upon the dose.

C. Naturally occurring chemicals are more poisonous to humans than synthetic chemicals.

Problem 2: Hazards and sources

One of the items below is a hazardous substance and the other four are sources of a hazardous substances. Which one is a hazardous substance?

A. clogged furnace

B. cigarette

C. a dog

D. paint applied before 1978

E. dust mite parts

A hazardous substance is a chemical that causes harm to our health. Dust mite parts cause an allergic reaction in many people. The source of dust mite parts is dust mites. Dust mites live in carpets, bedding and curtains.

Problem 3: Routes of entry

Which of the following is NOT a possible route of entry for a hazard?

A. ingestion

B. absorption

C. exposure

To cause harm to a person a hazard must enter the body. Merely being exposed will not cause harm if the hazard does not actually enter the body. There are three primary ways that a hazard can get into humans: through the gut, called ingestion; through the skin, called absorption; and through the lungs, called inhalation.

For example, a pack of cigarettes in a man’s shirt pocket does not cause harm to him because nothing from the cigarettes has entered his body. If, however, he smokes one of the cigarettes, the smoke has entered his body through his lungs and can cause harm.

D. inhalation

Problem 4: How chemicals are processed in the body

When DDT, a pesticide, enters the human body, it is ______________________.

A. water soluble and is easily excreted in urine.

B. stored in the bones.

C. not toxic, but is processed by enzymes and becomes a different compound which is toxic.

D. fat soluble and can be stored in fat tissue.

After a chemical enters the body, it is carried by the blood to different locations. What happens next depends on the size, shape and solubility of the chemical. Solubility means whether it can dissolve in water or lipids. Lipids are a type of fat. For example, butter is not water soluble – if you mix butter and water, the butter floats on top of the water because it cannot mix in. DDT is not very soluble in water, so it gets stored in fats and can remain in the body for a very long time.

Problem 5: Dose

Who has the largest dosage of aspirin?

A. an adult woman who weighs 125 lb and took 300 mg of aspirin

B. a teenage boy who weighs 135 lb and took 600 mg of aspirin

C. a baby who weighs 20 lb and took 100 mg of aspirin

D. a chihuahua who weighs 5 lb and took 50 mg of aspirin

The dose is the specific amount of a chemical that enters the body. Dosage is the amount of chemical per unit of body weight. Often the two words are used interchangeably. For example the adult woman weighs 125 lb and took 300 mg of aspirin. Her dose is 300mg/125 lb or 2.4 mg/lb. It is important to express dose in terms of body weight because a small person who ingests the same amount of a chemical as a large person receives a much higher dose.

Problem 6: Measuring dose

Which will NOT help you determine the dose of a hazardous gas received by a person?

A. their respiration rate

B. their length of exposure to the gas

C. the source of the gas

Knowing the source of a hazard will help the scientists to reduce exposure in the future, but will not help to determine how much a person has in their body. When scientists cannot directly measure the amount of a toxic chemical in the blood, they estimate exposure by looking at other factors. They determine things such as how fast a person was breathing, how long they were exposed, how often they were exposed, how easily the gas is absorbed and the concentration of the hazard.

D. their frequency of exposure to the gas

E. the concentration of the gas

F. the gas’s chemical and biological properties

Problem 7: Dose and response

Most hazardous substances exhibit a “dose-response relationship” What does this mean?

A. The harm caused by the hazard increases as the amount of hazard entering the body (dose) increases.

The dose response curve is the relationship between the amount of the hazard entering the body and the amount of harm it causes. A typical dose response curve looks like this one for the chemical alcohol.

B. It does not matter how big a dose you receive, you will always have same amount of harm/sickness.

C. Exposure to the hazard always results in harm.

D. Fifty percent of the people will die when exposed to 0.1 mg/kg.

Problem 8: Factors affecting dose

A family home has a clogged furnace that is producing carbon monoxide, a hazardous gas. Which family member is likely to be harmed the most?

A. Billy, the son who is in 1st grade

B. Baby Shea, who is going to be in preschool next year

The three important factors here are length of exposure, age and size. Baby Shea is most likely to be harmed because 1) he is the youngest and therefore smallest person in the house, and 2) along with his mother, Mrs. Nguyen, he spends the most time in the home.

C. Karla, the nanny who cares for the toddler every weekday morning

D. Ms. Nguyen, the mother who works at home

E. Mr. Nguyen, the father who works at the University

Problem 9: Factors affecting individual susceptibility

All of the people listed below live in the same house. Who is most likely to experience toxic effects from the second-hand smoke?

A. the grandmother, who is very fit

B. the mother, who smokes

C. the father, who smokes

D. the teenage daughter, who has asthma

A person’s health status can affect their response to a hazard. In this case, the daughter who has asthma is most likely to suffer harmful effects because her lungs are already experiencing an illness and are less healthy than the other people who live there.

E. the son, who is in 5th grade

Problem 10: Hazard control

There are several ways to control or reduce your exposure to a hazard. Opening a window in a room full of people who are smoking is an example of controlling your exposure to environmental tobacco smoke by __________________.

A. treating the symptoms of the hazard

B. diluting the hazard

By opening the window, fresh air will enter the room and the concentration of cigarette smoke will be reduced. This decreases your exposure to cigarette smoke, but does not completely eliminate exposure.. Other ways to control a hazard are removing the source of the hazard,wearing protective gear, distancing yourself from the hazard, and treating the symptoms caused by the hazard.

C. distancing yourself from the hazard

D. removing the hazard

Problem 11: Environmental health sciences professions

Which environmental health scientist would determine ways to prevent and reduce exposure to second hand smoke?

A. a toxicologist

B. an epidemiologist

C. an industrial hygienist

Toxicologists study the way in which hazards harm the body. Pharmacologists study the beneficial effects of chemicals. Industrial hygienists study how to stop or prevent exposure to hazards. Epidemiologists study what health problems occur in groups of people and investigate the causes. Occupational and Environmental Medicine physicians diagnose and treat patients exposed to health hazards and in their work or other environments.

D. an occupational and environmental medicine physician

E. a pharmacologist

Kidneys and Metals Problem Set

Problem 1: Kidney anatomy and function

What is one primary function of the tubules in the kidney?

A. filtering water and solutes out of the blood

B. reabsorption of water and solutes

The kidneys’ job is to filter and remove wastes from the blood. The glomerulus filters out wastes. The tubule reabsorbs water and non-wastes so that they can be reused by the body.

C. producing bile

D. transporting filtered blood to the lungs

Problem 2: Metals in the body

Which of the following is NOT a normal function/role of metal in the body?

A. iron in the heme of hemoglobin

B. calcium in the bones

C. cobalt in vitamin B12

D. phosphorus in ATP

E. arsenic in ATP

When arsenic is incorporated into ATP, it interferes with the normal function of ATP, which is to provide energy to cells.

Problem 3: Properties of metals and health implications

Which of the following is NOT characteristic of metals?

A. Metals are often charged ions.

B. Metals can be destroyed or degraded in the body.

Metals are elements, so they cannot be destroyed or broken down. With other types of toxic substances, one way the body detoxifies them is to break them down into different substances, but that is not possible with metals. Metals can sometimes be made less toxic by the addition of chemical groups to the metal.

C. Metals easily bond to other molecules.

D. Metals can have various oxidation states.

Problem 4: Sources of metals in the environment

Who is LEAST likely to be exposed to toxic metals?

A. a technician working on a computer component board assembly line

B. a person who drinks water from a ground water well

C. a person smoking a cigarette

D. a person working on a new home computer

Cigarettes, old paints, ground water, and computers can all contain toxic metals. People are least likely to be exposed from a personal computer because the metals in it are completely contained and in a state where the human is very unlikely to be exposed.

E. a painter renovating an 100 year old home

Problem 5: Types of metal toxicity

One of the ways that lead makes people sick is by interfering with the protein that helps make hemoglobin. The result is an anemic like condition where your blood can’t carry enough oxygen to keep you healthy. This is an example of what mechanism of metal toxicity?

A. enzyme inhibition

Many metals exert their toxic effects by interfering with enzymatic reactions in the body cells. Enzymatic reactions in the body are chemical reactions that are made possible by special proteins called enzymes. For example, hemoglobin is manufactured by a complex series of enzymatic reactions. Five of the enzymes involved in hemoglobin synthesis do not work very well at all in the presence of lead; that is, they are “inhibited” by lead. This can lead to anemia, which is a reduction in the number of red blood cells.

B. carcinogenicity

C. disruption of subcellular organelles

D. corrosion

Problem 6: Target organs for metals

Why is the kidney often a target for toxic chemicals such as metals?

A. because toxicants enter the body through the stomach and intestines and are then transported to the kidney

B. because the kidney has a very large surface area in direct contact with the blood

C. because there is very high blood flow to the kidney and it can concentrate substances

The kidneys are a target for metals, meaning they are usually affected by metals. Even though they comprise only 0.5% of the total human body weight, they receive about 25% of the body’s blood flow. The kidney’s primary function in the body is to concentrate waste substances, but in the process they concentrate many other substances as well, including toxic metals.

D. because the kidney cannot regenerate damaged cells

Problem 7: Membranes and metals

Amino acids are filtered out of the blood in the glomerulus of the kidney, but amino acids are not a waste product. The body needs the amino acids, so they are reabsorbed from the filtrate back into the tubule cells of the kidney. After the an imo acids are concentrated in the tubule cells they must be transported back into blood. What type of transport is used to move the amino acids from the filtrate to the inside of the kidney cells?

A. passive diffusion

B. protein channels

C. active transport

Amino acids are moved into the kidney cells using secondary active transport. They are being moved against a concentration gradient from an area of low concentration to an area of high concentration.

Problem 8: Examples of metals that harm the kidneys

Itai-itai byo is a disease found among Japanese women. Scientists believe that it is caused by eating rice grown in soil containing _____________.

A. lead

B. mercury

C. cadmium

Cadmium is found in some soils in very high concentration. In Japan, women who eat rice grown on cadmium rich soils have anemia, damaged kidney tubules, and bone and mineral loss. Scientists believe they understand some of the mechanisms by which cadmium causes damage. Normally cadmium is excreted from cells when it binds to a protein called metallothionein (CdMT). This serves to protect most cells from damage, but in the kidneys the cadmium metal-protein complex is easily absorbed in the tubules. Once inside the kidney cells, the cadmium is released from the MT protein and can accumulate to toxic levels.

D. chromium

Lung Toxicology Problem Set

Problem 1: Lung anatomy

Which of the following is NOT found in the human lung?

A. bronchiole

B. trachea

When you inhale, air moves from the nose and mouth, down to the larynx, down through the trachea. It does not reach the lungs until the trachea branches. The branched air passages are called the bronchi. The bronchi carry the air into the lungs. Each bronchus divides 20-30 times, becoming the bronchiole which take the air to the different parts of the lungs. Eventually the air reaches a cluster of “blind sacs” called alveoli, which is where the actual gas exchange occurs. An adult human can have up to 300 million alveoli in his or her lungs.

C. bronchi

D. alveoli

Problem 2: Alveolar structure

Which of the following alveolar cell types clean particles deposited in the lungs?

A. macrophages

Lung tissue consists of several types of cells. Macrophages in the alveoli are scavenger cells that work to keep the lung free of “foreign” materials.

B. epithelium type I

C. epithelium type II

D. fibroblasts

E. capillaries

Problem 3: Lung function

One of the primary functions of the alveoli is to create a large surface area in the lungs. Why is a large surface are so important?

A. for energy storage

B. to remove toxins from the blood

C. to store oxygen for future use

D. for gas exchange

Gas exchange is the primary function of the lung. Gas exchange occurs by diffusion, thus the rate of gas exchange is dependent on surface area. The alveoli serve to provide a large surface area in the lungs.

E. for the Krebs cycle

Problem 4: Lung development

When do the alveoli develop in lungs in humans?

A. during the first 1-2 years of life

Human lungs are not completely developed at birth. The development of the alveoli continues after birth. New alveoli form by a process called septation. The existing alveoli grow new septa, or walls, leading to increased surface area.

B. in the 1-5th week of pregnancy

C. between 3 and 5 years of age

D. between 3 and 5 years of age

E. between 3 and 5 years of age

Problem 5: Causes of death in the US

Which of the following causes the most deaths in the US?


B. motor vehicles

C. homicide

D. smoking

Of the factors listed, smoking causes the most deaths in the US. Smoking can cause death in several ways including stroke, heart disease, lung cancer, emphysema and other diseases and cancers.

E. alcohol

Problem 6: Toxicity of environmental tobacco smoke

Which statement do you agree with?

A. Environmental tobacco smoke (ETS), also known as secondhand smoke, has LESS toxic compounds than directly inhaled tobacco smoke.

B. Environmental tobacco smoke (ETS), also known as secondhand smoke, has MORE toxic compounds than directly inhaled tobacco smoke.

ETS has more toxic compounds because the smoke sucked through the cigarette and inhaled by the smoker has been burned at a higher temperature then the smoke that is coming off the end of the cigarette. This higher temperature burning destroys or inactivates certain of the toxic compounds.

Problem 7: PM10

What is PM10?

A. the number of packs per day that cause lung cancer in 10% of the population

B. particles which are small enough to be deposited in the lungs

The air we breath contains lots of little particles of matter such as pollen, and dust. Particles that are smaller than 10 microns in diameter can get all the way down into the alveoli in the lungs. They can cause tissue damage as they hit the lung tissue. These tiny particles can also damage the lung by causing irritation which can lead to scarring of the lung tissue.

C. a measure of the amount of pollen in a certain volume of air

D. a measure of the severity of an asthma attack

Problem 8: Oxidants

Oxidants are one toxic component of cigarette smoke. Why are they dangerous?

A. They block surfactant secretion so that alveoli collapse.

B. They block the oxygen carrying capacity of hemoglobin.

C. They cause cilia to quit beating so lungs get clogged with particles.

D. They can damage the DNA of lung cells much like the sun damages skin cells.

Oxidants cause cell damage by creating free radicals. Free radicals are highly reactive molecules which can bind to DNA and cause mutations. Such mutations could eventually lead to cancer.

Problem 9: Asthma and chronic obstructive pulmonary disease

Asthma is caused by decreased airflow in and out of the lungs due to:

A. small abnormalities in airways

B. reversible bronchial spasms

Asthma is due to a decrease in airflow in the major airways of the lungs. It can be caused by muscle spasms in the airways, swelling of cells lining the airways and excess mucus in the airways. Asthma is one of three respiratory diseases called “chronic obstructive pulmonary disease” that are often caused by smoking. The other two chronic obstructive pulmonary diseases are chronic bronchitis and emphysema. Chronic bronchitis is caused by small abnormalities in the airways. Emphysema is caused by destruction of the alveolar walls.

C. destruction of alveolar walls

D. allergic reaction in lung tissues

The Biology Project Home > Chemicals & Human Health

Environmental Tobacco Smoke and Lung Development Analyze scientific data to learn how second-hand smoke affects lung development and human health.

Kidneys and Metals Explore the world of renal toxicology, and learn the effect of metals on the kidneys and on kidney cells.

Toxicology Discover ways chemicals can affect human health and develop an understanding of fundamental principles of toxicology.

Lung Toxicology Review the basics of lung anatomy and function and learn about toxicology in the lungs, diseases of the lungs, and environmental tobacco smoke.

The Southwest Environmental Health Sciences Center has supporting materials for the Chemicals and Human Health site and lots of other environmental health activities and curricula.

Hydroville The good citizens of Hydroville need you to help them solve their environmental health problems. A website developed by the Hydroville Curriculum Project at Oregon State University.

Arizona Poison and Drug Information Center is a resource for information on natural and human-made poisonous chemicals.

The National Institute of Environmental Health Sciences :

Kids’ Page has lots of fun activities for kids including games, brainteasers, and current hot topics in environmental health sciences.

The National Institute of Environmental Health Sciences: Teacher Support has information and curricula for teachers.

The Biology Project Home > Chemicals & Human Health

oxicology Problem Set

This problem set is designed to help you understand basic principles of toxicology. You will learn what a hazard is, where hazards can come from, how they affect humans, and methods to control hazards. You will also learn about careers in the environmental health sciences.

  • Natural and human-made chemicals

  • Hazards and sources

  • Routes of entry

  • How chemicals are processed in the body

  • Dose

  • Measuring dose

  • Dose and response

  • Factors affecting dose

  • Factors affecting individual susceptibility

  • Hazard control

  • Fields in the environmental health sciences

Instructions: Each topic page has a multiple choice question designed to help you learn the concepts. If you click on the correct answer, you will see the word “correct” along with reinforcing information. If you click on an incorrect answer, you will be given a tutorial page. You can also go directly to the tutorial page by clicking on the tutorial button. Enjoy yourself – it doesn’t matter if you select the right or wrong answer – the point is to learn!

The Southwest Environmental Health Sciences Center

The Biology Project

The University of Arizona

Wednesday, October 8, 1997

Contact the Development Team

All contents copyright © 1997. All rights reserved.


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