Warm-Up Health Stats

Section 3

306 Chapter 12

Objectives Before class begins, write the objectiveson the board. Have students copy theobjectives into their notebooks at thestart of class.

After students have completed thewriting assignment, have volunteersshare their ideas with the class.Students should point out that thetrend of the graph line shows a risein ER visits for asthma from 1992until 1998, after which there is a fall.Students might suggest that air pollution contributed to risingasthma rates. Perhaps emergencyroom visits dropped because at-hometreatments became more effective.

Teaching Transparency W41

1. Focus

Respiratory Health

306 Chapter 12

Section 3

Objectives� List the functions of the

respiratory system.� Describe how air travels

through your respiratorysystem, and how youbreathe.

� Identify ways to keep therespiratory system healthy.

Vocabulary• alveoli• diaphragm• asthma• bronchitis

The Respiratory SystemA person can survive weeks without food and days without water, but onlyminutes without oxygen. Your respiratory system brings a continuoussupply of oxygen from the air into your body. As you have read, your car-diovascular system transports this oxygen to all of your body cells. After thecells use the oxygen to break down glucose for energy, they are left withcarbon dioxide that must be expelled from the body. The respiratorysystem is responsible for bringing oxygen from the outside environmentinto the body. It also removes carbon dioxide from the body.

The Pathway of Air When you breathe in, or inhale, much morethan just air enters your body. With every breath, you also take in suchthings as dust, pollen, and microorganisms that can cause disease. Most ofthese substances never reach your lungs. Cells lining your nasal cavitiesrelease mucus, which traps particles. Mucus also warms and moistens theair as it passes through your nasal cavities. On its way to the lungs, airpasses through the nose, pharynx, larynx, trachea, and bronchi. Followthe pathway of air from the environment to your lungs in Figure 9.

Respiratory Health

Health Stats What trend does this graph reveal?

Describe some factors that could contribute to therise and fall of asthma emergencies.

Asthma Emergency Room Visits

Vis

its

per

10

,00

0 p

eop

le

1992 1994 1996 1998 2000 2002

60

65

70

75

80

0

55

Sensitive Issues Be aware that some students withasthma may be sensitive about sharing their experiences with theclass. If you know students with asthma in your class, ask them aheadof time if they mind talking abouttheir experiences.

FYI !FYI !Asthma and Physical ActivityPhysical activity is important for the healthof the body and the mind. There are waysto help teens with asthma stay active andreap the benefits of physical activity.Asthma and Physical Activity in the School,

available through the National Heart, Lung,and Blood Institute, offers advice to teach-ers and coaches who want to help studentswith asthma participate in physical activities.

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Special NeedsStudents who need extra help, as well asvisual and tactile learners, may learn moreabout the respiratory system by drawing it.Give each student a sheet of tracing paperor thin unlined paper. Ask students to trace

the outline of the person in Figure 9. Thenstudents should draw the structures, labelthem, and describe them in their ownwords. Check students’ completed draw-ings for errors and omissions.

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Reading/Note Taking 3-1

Adapted Reading/Note Taking 3-1

The Respiratory System

Visual Learning: Figure 9Teaching Transparency 31Have students write the name of eachlabel in Figure 9 on an index card. Havethem organize the labels by the order inwhich air passes through the respiratorysystem. Suggest they write a questionthey have about each structure on thecard. Have them fill in the answers asthey read the section. Caption Answer Carbon dioxide movesfrom the lungs through the bronchi,through the trachea, through the larynx,through the pharynx, and out throughthe nose or mouth.

Active LearningAsk students to tilt their heads backwardand place the fingers of one hand on thefront of the neck. Then ask students tomove the fingers up and down the neck.Ask: What are the ridges you feel upand down your neck? (the rings of thetrachea) Ask students to keep their fingers in place as they swallow. Explainthat the movement they feel is theepiglottis sealing the larynx. Ask: Whatdoes the sealing of the larynx by theepiglottis prevent? (It prevents food orliquid from entering the trachea.)

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EL

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2. Teach1 Nose and Nasal Cavities

Air enters the body through two nostrilsand then moves into the nasal cavities.

6 LungIn the lungs, bronchi divide like branches of a tree into smaller tubes.At the end of the smallest tubes arethe alveoli. Oxygen and carbondioxide are exchanged in alveoli.

5 BronchusThe trachea divides into twobronchi (singular, bronchus),which are cartilage-ringed tubesthat enter each lung.

4

3 Epiglottis and LarynxAir travels from the pharynx to the larynx. The larynx contains the vocal cords. When youswallow, the epiglottis seals the larynx to preventfood or liquid from entering the trachea.

2 PharynxNext air enters the pharynx, or throat.The mouth also connects to the pharynx.

CapillaryBlood richin oxygen

Blood rich incarbon dioxide

CiliaCilia line most of the respiratorytract. Cilia capture mucusthat contains dust andmicroorganisms andsweep it toward yourthroat to be swallowed.

TracheaThe trachea, or windpipe,leads from the larynx to the lungs.

Alveoli

The Respiratory System

Cardiovascular and Respiratory Health 307

FIGURE 9 On its path to the lungs, airpasses through several structures where itis filtered, warmed, and moistened.Predicting What path does carbondioxide take on its way out of the body?

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Chapter 12, Section 3

Class DiscussionAfter students have read about gasexchange, reinforce the connectionbetween the cardiovascular system andthe respiratory system. Ask: Where doesthe carbon dioxide come from thatpasses from blood into the alveoli? (It is a waste product that passes from bodycells into the blood.) When the oxygenin the alveoli passes into the blood, towhat chamber of the heart does thatblood first go? (to the left atrium) Whyis the oxygen that is part of theexchange in the alveoli needed by thebody? (Body cells use oxygen in theprocess that extracts energy from nutrients.)

Teacher DemoTo demonstrate how the diaphragmworks, borrow a model of the lungsand diaphragm from a biology teacher.A common apparatus consists of one ortwo small balloons to represent thelungs. These balloons are attached to atube within a glass bell jar. The bottomof the jar is sealed with latex, whichrepresents the diaphragm. When youpull down on the “diaphragm,” the“lungs” inside the bell jar inflate. Ask:What will happen to the “lungs” whenthe “diaphragm” moves upward? (The“lungs” will deflate as air moves out ofthem.) Tell students that this modelillustrates how changes in air pressurecause the lungs to expand and contract.

Visual Learning: Figure 10Teaching Transparency 32Have students examine the process ofinhalation and exhalation shown in thefigure. Then ask them to place onehand on their abdomen as they breathenormally. Ask: Why does your abdomenmove in and out as you breathe?(When the diaphragm contracts andflattens, it pushes the abdomen out.The reverse occurs when the diaphragmrelaxes and moves upward.)

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and HealthPercentages

On page 309, students will learn thatapproximately 23 million people in theUnited States have asthma. Based on this data, have students estimate the percentage of people in the United States

with asthma. For this exercise, assumethat the United States population is 300million. (23 � 300 � 0.077; 0.077 � 100 �7.7 percent)

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308 Chapter 12

Gas Exchange At the end of the smallest tubes in the lungs are mil-lions of tiny sacs that look like bunches of grapes. These sacs, called

(al VEE uh ly) (singular, alveolus), are where gases are exchangedbetween the air and the blood. You can see an illustration of alveoli inFigure 9 on the previous page. Oxygen passes through the thin walls of analveolus and through a thin capillary wall into the blood. At the sametime, carbon dioxide passes from the blood into the alveoli.

The Breathing Process How does air get into and out of yourbody? The breathing process is controlled by the actions of muscles inyour ribs and chest. As you can see in Figure 10, breathing takes place intwo stages.

� Inhalation When you inhale, or breathe in, rib muscles pull the ribsup and out. At the same time the (DY uh fram), a dome-shaped muscle that lies below the lungs, flattens. The chest cavityenlarges, the volume of the lungs increases, and air flows in.

� Exhalation When you exhale, or breathe out, the diaphragm movesupward. The rib muscles relax and the ribs drop. These movementsmake the chest cavity smaller and squeeze air from the lungs.

diaphragm

alveoli

FIGURE 10 When you inhale, thediaphragm flattens. Pressure in theexpanded lungs decreases, causingair to flow in. When you exhale, thediaphragm curves upward. Pressurein the lungs increases, pushing airout of your lungs.

Rib cagemoves upand out

The diaphragmcontracts andflattens.

The rib cage returnsto its original position.

The diaphragmrelaxes andmoves upward.

InhalationThe volume of the lungs increases,and air flows in.

ExhalationThe volume of the lungs decreases, andair is pushed out.

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Gifted and TalentedHave interested students further investi-gate asthma. Ask them to find out aboutthe causes of asthma, the triggers that pro-duce an asthma attack, the symptoms ofthe disorder, and the treatment of asthma.Point out to students that asthma is agrowing problem in the United States and

other industrialized countries. Ask studentsto try to find explanations for the increaseof asthma. Have them focus some of theirattention on how air pollution affects aperson with asthma. Ask students to sharewhat they learn with the class.

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Keeping Healthy

Class Discussion Write the following question on thechalkboard: How often are you exposedto automobile exhaust, smoke, or dusteach day? Where do these exposuresoccur? Have students call out responsesand make a running list on the board.Students will likely be surprised at thelong list of respiratory system irritantsthey are exposed to every day.

Cooperative LearningHave small groups work together tomake a list of “Do’s” and “Don’ts”regarding respiratory health. (For example, students might list: “Do getregular exercise” and “Don’t exerciseoutdoors on days when the air is verypolluted.”) Give groups a chance toshare their lists. Call on students toexplain how following these “Do’s” and “Don’ts” contributes to a healthyrespiratory system.

Journal WritingAsk students to write a journal entry inwhich they explain why it is importantfor a person to keep his or her respira-tory system healthy. Ask students to thinkof times when they’ve been tempted tosmoke tobacco and describe why refusingtobacco is important to maintain goodrespiratory health.

Allow students to answer this question in their

private journals.

Content UpdateUse the Web Code toaccess up-to-date information aboutasthma. Have students complete the Web activity.

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Connect to

YOUR LIFE

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L2� Pollen� Exercise� Tobacco smoke� Pet dander� Dust mites� Mold� Cold air� Perfumes

Common Asthma Triggers

FIGURE 11 People with asthmacan lead active lives if they followtheir treatment program. Theyshould also avoid or limit exposureto their particular triggers. Peoplewith exercise-induced asthmashould work with a doctor to findways to exercise safely.

Cardiovascular and Respiratory Health 309

Keeping HealthyWhat can you do to keep your respiratory system healthy? You can keepyour respiratory system healthy by avoiding tobacco smoke and air pol-lution and treating asthma if you have it. In addition, avoid respiratoryinfections, get regular exercise, and maintain a healthy weight.

Avoiding Smoking and Air Pollution The most importantthing you can do to protect your respiratory system is not to smoke. Overtime, exposure to tobacco smoke and other air pollutants can seriouslyharm your respiratory health. In Chapter 16 you will learn how smokingcan lead to serious respiratory system disorders such as chronic bronchi-tis and emphysema.

It is also important to avoid exposure to air pollutants whenever possi-ble. If you do work that generates fumes or dust, such as sweeping agarage, wear a mask. Work in a well-ventilated area when you paint or useother chemicals that produce fumes. Before exercising outdoors on a hot,sunny day, check local news reports for warnings about air quality.

Living With Asthma About 16 million adults and 7 million chil-dren in the United States have asthma. (AZ muh) is a disorder inwhich respiratory passageways become inflamed. During an asthmaattack, the passageways narrow until air can barely pass through. As aresult, the person wheezes, coughs, and has difficulty breathing. Attackscan range from irritating to life threatening. Substances or behaviors thatcause asthma attacks are called triggers. Common asthma triggers areexercise, allergic reactions, and stress.

Asthma is usually first diagnosed in childhood. Sometimes childrenoutgrow the condition. Many people with asthma take medications dailyto control their symptoms and avoid attacks. If an attack does occur, othermedications are taken for immediate relief.

What things do you do to keep your respiratorysystem healthy?

Connect to YOUR LIFE

Asthma

For: Updates on asthmaVisit: www.SciLinks.org/healthWeb Code: ctn-4123

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Other Healthful Behaviors You can practiceother important behaviors to protect the health of yourrespiratory system.

� Avoid Respiratory Infections From time to time,microorganisms will escape the mucus and sweep-ing cilia and infect your respiratory system. Forexample, is an infection that causes themucous membranes lining the bronchi to becomeinflamed. The inflamed membranes secrete a largeamount of thick mucus that must be removed bycoughing. In Chapter 21 you will learn about othercommon respiratory infections such as colds,influenza, and pneumonia. You will also learn waysto prevent and treat these infections.

� Get Regular Exercise A regular exercise programthat involves several minutes of repetitive, non-stopphysical activity is extremely important for main-taining respiratory health. Exercise helps your lungsbecome more efficient at taking in oxygen andeliminating carbon dioxide.

� Maintain a Healthy Weight Regular exercise willalso help you maintain an ideal weight. The respi-ratory system of an overweight person must workharder to deliver adequate oxygen than the systemof a normal weight person. Maintaining a reason-able weight will help you avoid straining yourrespiratory system.

bronchitis

Section 3 Review

Key Ideas and Vocabulary 1. What two functions does your respiratory system

perform?

2. List the structures that air flows through on its wayto the lungs.

3. Explain the action of the diaphragm when youinhale and exhale.

4. Identify five ways you can help your respiratorysystem stay healthy.

Critical Thinking5. Relating Cause and Effect In a healthy person,

how might coughing and sneezing protect therespiratory system?

6. Comparing and Contrasting Explain thedifference between the movement of oxygen andcarbon dioxide in the alveoli.

7. Evaluating Why is it important for someone withexercise-induced asthma to find ways to participatein physical activity?

FIGURE 12 Protect your respiratorysystem by wearing a mask when you dowork that generates dust or fumes.

SchoolHealth at

Asthma Attacks Talk to your school nurse,physical education teacher, or other studentsabout asthma. What are the most commontriggers for asthma attacks at school? Are attacksmore common at certain times of day or times ofyear? How are asthma attacks treated? Summarizeyour findings in a paragraph.

Health at School

Asthma Attacks Encourage studentsto ask what the procedures are whena student experiences an asthmaattack. To manage this activity, youmight assign pairs of students or smallgroups to interview the nurse or aspecific physical education teacher.Each student can then write a para-graph summarizing the findings.

3. AssessEvaluateThese assignments can help you assessstudents’ mastery of the section content.

Section 3 ReviewAnswers appear below.

Teaching Resources• Practice 12-3• Section 12-3 Quiz

ReteachPlay a quiz game in which you describe the function of a part of therespiratory system and students try toname that part. Go around the room,calling on one student after another,until most students show mastery of the information.

Enrich

Teaching Resources• Enrich 12-3

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L2

4. avoid smoking and air pollution, treat asthma if you have it, avoid respiratoryinfections, get regular exercise, and main-tain a healthy weight

5. Sample answer: Coughing and sneezing canremove microorganisms and foreign particlesfrom the respiratory tract.

6. Oxygen moves from the air in the alveoliinto the blood in the capillaries. Carbondioxide moves from the blood in the capillaries into the air in the alveoli.

7. Sample answer: Exercise helps your lungsbecome more efficient at taking in oxygenand eliminating carbon dioxide. Exercisealso benefits the cardiovascular system andother systems of the body.

1. It brings oxygen into the body andremoves carbon dioxide from thebody.

2. nose, pharynx, larynx, trachea, andbronchi

3. When the diaphragm flattens, youinhale. When the diaphragmmoves upward, you exhale.

Section 3 Review

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