Review and Reinforce How the Nervous System Workstegtscience.com/planbook/Life_Science/May122008/nervous_sys_hw.pdf · How the Nervous System Works Understanding Main Ideas ... The

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Name ____________________________ Date ____________________ Class ____________

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How the Nervous System Works

Understanding Main Ideas

Answer the following questions on a separate sheet of paper.

1.

What are three main functions of the nervous system? Give an example of each.

2.

What are the three kinds of neurons? How do they work together to produce a response to an environmental stimulus? Use an example in your explanation.

3.

How does a message travel across the gap at a synapse?

Building Vocabulary

Label the diagram below with the axon, axon tip, dendrite, and synapse.

Fill in the blank to complete each statement.

8.

A(n) ________________________ is what your body does in reaction to a stimulus.

9.

A bundle of nerve fibers is called a(n) ________________________.

10.

The message that a neuron carries is called a(n) ________________________.

11.

Any change or signal in the environment that can make an organism react is a(n) ________________________.

12.

A cell that carries information through your nervous system is called a(n) ________________________.

6.

4.

5.

7.muscle

The Nervous System

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Polygraph Test

A

polygraph,

or lie detector, test is sometimes used to help determine whether a person is telling the truth. In such a test, the subject (the person being tested) is connected to a polygraph machine that records information about his or her body. This information includes such things as heart rate, blood pressure, breathing rate, and sweat gland activity. An examiner (the person giving the test) asks the subject a series of questions. As the subject answers, the machine records changes in the subject’s body. The examiner uses these changes to determine whether the subject has answered the questions truthfully.

The polygraph test relies upon responses of the subject’s nervous system. If the subject gives an untruthful answer, fear of being caught in a lie triggers several responses that are largely involuntary. For example, fear might cause the subject’s heart rate to increase or even skip a beat, and these changes would be recorded by the polygraph. However, there is disagreement among scientists about how reliable polygraphs are. Some studies have shown that conditions such as lack of sleep or the use of some types of drugs can affect the results of a polygraph test.


1.

Why do you think it is important that a polygraph measures responses that are largely involuntary instead of responses that are voluntary?

2.

Sometimes subjects are given a “practice test” that will record their body’s response to telling a lie. In this test, the examiner tells the subject to think of a number between one and ten and to answer “no” to all questions. Then, the examiner asks “Is the number one?,” “Is the number two?,” and so on, until the examiner has asked the question for all the numbers from one to ten. Why is this a good practice test?

3.

Name a voluntary response and an involuntary response of the nervous system during a polygraph test.

Polygraphmachine

Pens that record responseson a moving sheet of paper

Blood pressure cuff – measuresheart rate and blood pressure

Metal plates on two fingers –measure activity of sweat glands

Rubber tubing aroundchest and abdomen – measures breathing rate

The Nervous System

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Name ― Date C 卜卜 Chapterl5 TheNeFvousSystem ・ Secfioon3S 口 mma ヴ

Sight and Hearing Key Concepts ･ How do your eyes enable you to see?

･ How do you hear and maintain your sense of balance?

Your eyes respond to the stimulus of light They convert that stimulus into impulses that your brain interprets, enabling you to see. When rays of light first strike the eye, they pass through the cornea, the clear hsbue that covers the front of the eye. Behind the cornea is the pupi1, the opening through which tight enters the eye. Around the pupil is the iris, a circular structure that regulates the amount of light entering the eye.

Light that passes through the pupil strikes the lens. The lens is a flexible structure that focuses light. Light finally strikes the retina, the layer of receptor cells that lines the back of the eye. There are two types of receptor cells: rods and cone;>. Rod cells work best in dim. lieht and allow vou to see black, white, and shades of gray. Cone cells work ; best in bright light and allow vou to see color Light hitting the retina causes nerve impulses to begin. The optic nerve carries nerve impulses from the retina to the ceiebrum. The brain interprets the signa1, turns the image right-ado up, and produces one image.

100k In at humans, an object, both each eyes eye 100k sees forward a slightly from d ifferent the front image. of the The head. brain When interprets you the impulses coming from your two eyes as one image. As a result, you can see in three dimensions, which means you can tell how near or far away the image is.

Your ears are the sense organs that respond to the stimulus of sound. The ears convert the sound to nerve impulses that your brain interprets. Sound is produced by material that is vibrating. The vibrations create Wiivos The ear is structured to receive sound waves.

The ear consists of three sections@@the external ear, middle ear, and nincr ear. The external ear helps gather sound waves. Sound waves move through the ear canal to the eardrum, which separates the outer car from the middle ear. The eardrum is a membrane that vibrates when sound waves strike it. Three tiny bones in the middle eiu ﾑ the hammer,, anvil/ and stirrup ﾑ transmit the vibrations from the eardrum to the cochlea in the inner ear. The cochlea is a snai1-shaped tube lined with receptors that respond to sound. These receptors create nerve impulses that are carried through the auditory nerve to the brain. Structures in your inner ear control your sense of balance. Above the cochlea are the semicircular canals, which are the structures that are responsible for your sense of balance

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Fill in the blank to complete each sentence.

8. The ________________________ contains receptors that convert sound vibrations to impulses that are sent to the brain.

9. Vibrations pass from the eardrum to the ________________________.10. The ________________________ sends electrical impulses from the rods

and cones to the brain.11. The ________________________ is a membrane in the ear that vibrates

when sound waves strike it.12. Each ________________________ in your inner ear helps you maintain

your sense of balance.

Sight and HearingUnderstanding Main IdeasAnswer the following questions on a separate sheet of paper.

1. How do we see? In your explanation, describe the parts of the eye and the path of light through the eye.

2. How do we hear? In your explanation, describe the parts of the ear and path of sounds through the ear.

Building VocabularyFrom the list below, label the diagram.

cornea

pupil

iris

lens

retina

The Nervous System ■ Review and Reinforce



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Name ____________________________ Date ____________________ Class ____________

Color Vision, ColorblindnessReceptor cells called cones enable you to see colors. The human eye has three different types of cones. People who are colorblind are missing at least one type of cone cell. Most people who are colorblind can see colors. They just can’t see as many colors as a person with all three types of cones. In addition, some colors may appear different to a person who is colorblind than to a person who has all three types of cones.

Because there are three types of cones, there are also three types of colorblindness. For example, people who do not have red cones cannot see red light. As a result, they cannot distinguish between the colors red and green. Those who do not have blue cones cannot see blue light; they cannot distinguish between the colors blue and yellow. People who lack green cones cannot see green light.

Everyone is colorblind during some part of their life. For example, you were born colorblind. Cone cells don’t start working until a person is about four months old. You also become colorblind in dim light. You may have noticed that when you first turn off your bedroom light at night, you can’t see anything at all. Then after a few minutes, the room seems to get lighter. The flowchart below shows why this happens.


1. Why does a darkened room appear to get lighter after a few minutes?2. One way scientists have learned about colorblindness is by studying

people who are colorblind in one eye, but have full color vision in the other eye. Such people are able to describe how colors appear to a person who has colorblindness in both eyes. How do you think they are able to do this?

3. What problem might a person who lacked red cones have at a traffic light? What is a possible solution to this problem?

4. The taillights of some cars and motorcycles appear very dark brown to some people with colorblindness. Why could this be dangerous?

5. Suppose a person’s eyes had no cones at all. How would this affect his or her color vision?

Light turned on.Cones are working.

Rods are not working.Room appears bright.

Light turned off.Cones do not work as well.Rods are not yet working.Room appears very dark.

After 7–10 minutes inthe dark, the rods

begin to work.Room appears lighter.

The Nervous System ■ Enrich


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Chapter 15 The Nervous System = Section 5 Summary

Alcohol and Other Drugs Key Concepts

Which body system is immediately endangered by drug use?

What are some commonly abused drugs and how does each affect the body?

m How does alcohol abuse harm the body?

To a scientist, a drug is any chemical taken into the body that causes changes in a person's body or behavior. Drug abuse is the deliberate misuse of drugs for purposes other than medical ones. Both legal and illegal drugs can be abused. Most abused drugs, such as marijuana, alcohol, and cocaine, are especially dangerous because of their immediate effects on the brain and other of the nervous system. In addition, long-term drug abuse can lead to addiction and other health &d social problems. M& abuseddrugs canalter, or change, a person's mood and feelings. Mood-altering drugs affect patterns of thinking and the way in which the brain interprets information from the senses.

If a person takes a drug regularly, the body may develop a tolerance to the drug. Tolerance is a state in winch a drug user needs larger and larger amounts of the drug to get the same effect. Tolerance can cause people to take an overdose and become unconscious or even die.

Repeated use of many commonly abused drugs can result in addiction. In addiction, the body becomes physically dependent on the drug. When the drug addict mis5es a few doses of the drug, the body reacts to the lack of the drug. The person is experiencing withdrawal, a period of adjustment that occurs when a person stops taking a drug. People can also become emotionally dependent on the feelings and moods produced by a drug.

Commonly abused drugs include depressants, stimulants, inhalants, hallucinogens, anabolic steroids, and alcohol. Many drugs affect the central nervous system, while others affect the overall chemical balance of the body. Depressants are drugs that slow down the activity of the central nervous system. Stimulants speed up body processes. Inhalants are inhaled, or breathed in. They can produce mood-altering effects. Hallucinogens can make people see or hear things that do not really exist. Some athletes try to improve their performance by taking anabolic steroids, synthetic chemicals that are similar to hormones produced in the body. They can cause mood changes and permanent physical damage.

Alcohol is a powerful depressant It is quickly absorbed by the digestive system. The amount of alcohol in the blood is usually expressed as blood alcohol concentra tion, or BAC. Heavy drinking, especially over a long period, can result in significant health problems. Alcohol abuse can cause the destruction of cells in the brain and liver, and can lead to addiction and emotional dependence. Abuse of alcohol can result in alcoholism, which is a disease in which a person is both physically addicted to and emotionally dependent on alcohol.

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Name ____________________________ Date ____________________ Class ____________

Alcohol-Related Traffic DeathsTraffic accidents are the leading cause of death in the United States for children under age 15. Between 1985 and 1996, 35,547 children under age 15 were killed in traffic accidents. Alcohol was involved in 8,482 of these deaths. Of the children killed in alcohol-related crashes, 68 percent were passengers in a car, 22 percent were pedestrians, and 8 percent were bicyclists.

The table below shows the ages of people who died in traffic accidents caused by drunk drivers in 1997 and 2001.


1. For which age group did the number of traffic deaths due to drunken drivers increase the most? How many more deaths were there in this age group in 2001 than 1997?

2. By about what percent did the total number of traffic deaths involving drunken drivers increase between 1997 and 2001?

3. About how many people died each day in 2001 due to traffic accidents involving drunken drivers?

4. How many people under age 16 were killed by drunken drivers in 1997 and 2001 combined?

5. What are three ways that the number of deaths due to drunken driving could be reduced?

Number of DeathsInvolving Drunken Drivers

Age Group 1997 2001

Under 16 670 584

16-20 2,096 2,366

21-24 2,053 2,421

25-34 4,031 3,800

35-44 3,356 3,709

45-54 1,862 2,382

55-64 905 1,039

65-74 604 558

Over 74 454 481

Total 16,031 17,338

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Alcohol and Other DrugsUnderstanding Main IdeasFor items 1–3, complete the following Venn diagram by writing the letter of each characteristic in the correct section.

a. slow down the central nervous systemb. can be abusedc. include alcohol and heroind. speed up body processese. act on the nervous systemf. include nicotine

Answer the following in the spaces provided.

4. What are some of the common effects of long-term abuse of alcohol? ________________________________________________________________________

________________________________________________________________________

Building VocabularyWrite a definition for each of the following terms on the lines below.

5. drug abuse ________________________________________________________________________

________________________________________________________________________

6. alcoholism ________________________________________________________________________

________________________________________________________________________

7. tolerance ________________________________________________________________________

________________________________________________________________________

8. withdrawal________________________________________________________________________

________________________________________________________________________

9. depressant________________________________________________________________________

________________________________________________________________________

The Nervous System ■ Review and Reinforce

Stimulants

1. 2. 3.

Depressants


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