Unit 10 The Human Body The Human Advance Planning

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Unit Projects

Unit ProjectsUnit ProjectsUnit Projects

Unit 10Unit 10Advance PlanningChapter 34■ Order slides of human skin for

the Alternative Lab.

Chapter 35■ Borrow a human skull or a

large animal skull for the firstQuick Demo.

■ Order slides of the pancreasfor the second Quick Demo.

■ Purchase whole kidneys thatstill have the adrenal glandsattached for use in the thirdQuick Demo.

■ Order thyroid/parathyroidslides for MiniLab 35-2.

Chapter 36■ Acquire models of ears, eyes,

skin, and nose for the Display.■ Order Daphnia for the BioLab.

Chapter 37■ Order Daphnia for the Micro-

scope Activity.■ Order a whole kidney for the

Quick Demo.

Chapter 38■ Purchase a microscope slide

showing a cross-section oftestis for the Quick Demo andthe Inside Story.

■ Purchase a microscope slideshowing a cross-section ofovaries for the Inside Story.

■ Order sea urchin sperm andeggs for MiniLab 38-1.

■ Obtain slides of sea star devel-opment for the Quick Demo.

Chapter 39■ Purchase bacterial culture and

antibiotic disks for the Altern-ative Lab.

■ Purchase blood smear slidesfor MiniLab 39-2.

Using the LibraryLinguistic Have student groups pre-pare a report on how an injury to

one system structure—such as torn carti-lage or a ruptured spleen—can disruptthe whole system. L3

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InterviewInterpersonal Have student groupsinterview a nurse or physician

about a disease or disorder that affectsmainly one body system. This could be aninherited disorder, such as sickle cell ane-mia, or a disease that disrupts the system,such as pneumonia. Have students pre-sent their findings in a report. L2

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Final ReportHave student groups present their find-ings about body systems to the other stu-dents in the class. L2

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The HumanBody

The HumanBody

As the sprinter crosses the finish line, the crowd cheers. Winning a race requiresthe coordination of many different body systems—systems that don’t workindependently, but interact in hundreds of complex ways.

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UNIT CONTENTSUNIT CONTENTS

UNIT PROJECTUNIT PROJECT

Use the Glencoe Science Web Site for more project

activities that are connected to this unit.www.glencoe.com/sec/science

Unit 10Unit 10

Protection, Support, andLocomotion

The Digestive and EndocrineSystems

The Nervous System

Respiration, Circulation, and Excretion

Reproduction and Development

Immunity from Diseases

The Human BodyBIODIGESTBIODIGEST

Unit ProjectsUnit ProjectsUnit Projects

Unit Projects

Unit 10Unit 10

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The Human Body

Unit OverviewUnit 10 describes the organs andsystems of the human body andhow they interact with oneanother. Chapter 34 describes theskin, skeletal, and muscular sys-tems. The digestive and endo-crine systems are covered inChapter 35.

Chapter 36 looks at the ner-vous system’s control of the bodyand the effects of drugs on bodysystems. Included is a Focus OnThe Brain, which describes func-tions of the brain in more detail.Respiration, Circulation, andExcretion follow in Chapter 37.

Chapter 38 provides a discus-sion of human reproduction anddevelopment. Chapter 39 out-lines the function of the immunesystem and ends with a discussionof how AIDS affects the immunesystem.

Introducing the UnitAsk students which systems areimportant for a runner to succeedat a track meet. Then discuss thefollowing questions with theclass. Which systems are involvedin the excitement and tension therunner feels before the race?Which systems are involvedwhen the runner is racing?

Interactions of BodySystemsHave students do one of the projects for this unit as described on the GlencoeScience Web Site. As an alternative, students can do one of the projectsdescribed on these two pages.

DisplayVisual-Spatial Students can collectpictures of buildings from maga-

zines and make a display. For each pic-ture, encourage students to drawanalogies between parts of the buildingand parts of the body that have similarfunctions.

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ModelingKinesthetic Have student groupsdesign and make a model of one

body system, such as the nervous orendocrine system. They may use anymaterials they wish.

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http://www.glencoe.com/sec/science

Chapter 34 OrganizerChapter 34 Organizer

Activities/FeaturesObjectivesSection

MATERIALS LIST

BioLabp. 940 stopwatch or clock with secondhand, graph paper, small weights,wooden box or step stool

MiniLabsp. 925 ink pad, index cards, magnify-ing glass, acetone or nail polishremoverp. 937 metric ruler

Alternative Labp. 924 microscope, prepared slide ofhuman skin

Quick Demosp. 927 nonep. 930 X ray of human bodyp. 930 skeletonp. 931 chicken bone, vinegar or 10%hydrochloric acidp. 932 fresh beef bone(2)p. 936 fresh chicken feet, freshchicken wings

Need Materials? Contact Carolina Biological Supply Company at 1-800-334-5551or at http://www.carolina.com

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Teacher Classroom Resources

Assessment Resources Additional Resources

Products Available FromGlencoeTo order the following products,call Glencoe at 1-800-334-7344:CD-ROMNGS PictureShow: Human Body1Curriculum KitGeoKit: Human Body 2Transparency SetNGS PicturePack: Human Body 1VideodiscSTV: Human Body

Products Available FromNational Geographic SocietyTo order the following products,call National Geographic Societyat 1-800-368-2728:VideosIncredible Human MachineMuscular and Skeletal Systems(Human Body Series)

Teacher’s Corner

922B

Protection, Support, and Locomotion

Protection, Support, and Locomotion

TransparenciesReproducible MastersSection

Skin: The Body’sProtection

Bones: TheBody’s Support

Muscles forLocomotion

Section 34.1

Section 34.2

Section 34.3

Teacher Classroom Resources

Section Focus Transparency 81Basic Concepts Transparency 61

Section Focus Transparency 82Basic Concepts Transparency 62Basic Concepts Transparency 63

Section Focus Transparency 83Basic Concepts Transparency 64Reteaching Skills Transparency 49

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Assessment Resources Additional ResourcesSpanish ResourcesEnglish/Spanish AudiocassettesCooperative Learning in the Science ClassroomLesson Plans/Block Scheduling

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Chapter Assessment, pp. 199-204MindJogger VideoquizzesPerformance Assessment in the Biology ClassroomAlternate Assessment in the Science ClassroomComputer Test BankBDOL Interactive CD-ROM, Chapter 34 quiz

Refer to pages 4T-5T of the Teacher Guide for an explanation of the National Science Education Standards correlations.

Skin: The Body’sProtectionNational Science EducationStandards UCP.1, UCP.2,UCP.5; A.1, A.2; C.5; F.1,F.5; G.1 (1 session, 1/2 block)

Bones: The Body’sSupportNational Science EducationStandards UCP.1, UCP.2,UCP.5; B.2, B.6; C.5; D.1;E.1; F.1, F.6 (2 sessions, 1block)

Muscles forLocomotionNational Science EducationStandards UCP.1-3, UCP.5;A.1, A.2; C.5; E.1, E.2; F.1, F.6;G.1 (2 sessions, 11/2 blocks)

1. Compare the makeup and functions ofthe dermis and epidermis.

2. Recognize the role of the skin inresponding to external stimuli.

3. Outline the healing process that takesplace when the skin is injured.

4. Identify the structure and functions ofthe skeleton.

5. Compare the different types of movablejoints.

6. Recognize how bone is formed.

7. Classify the three types of muscles.8. Analyze the structure of a myofibril.9. Interpret the sliding filament theory.

Inside Story: The Skin, p. 924MiniLab 34-1: Examine Your Fingerprints, p. 925Problem-Solving Lab 34-1, p. 926

Problem-Solving Lab 34-2, p. 933Physics Connection: X rays—The PainlessProbe, p. 942

Problem-Solving Lab 34-3, p. 936MiniLab 34-2: Look at Muscle Contraction,p. 937Inside Story: A Muscle, p. 938Design Your Own BioLab: Does fatigueaffect the ability to perform an exercise? p. 940

Section 34.2

Section 34.1

Section 34.3

Reinforcement and Study Guide, p. 151BioLab and MiniLab Worksheets, p. 151Content Mastery, pp. 169-170, 172

Reinforcement and Study Guide, pp. 152-153Concept Mapping, p. 34Critical Thinking/Problem Solving, p. 34Laboratory Manual, pp. 247-250Tech Prep Applications, pp. 43-44Content Mastery, pp. 169, 171-172

Reinforcement and Study Guide, p. 154BioLab and MiniLab Worksheets, pp. 152-154Laboratory Manual, pp. 251-254Content Mastery, pp. 169, 171-172Inside Story PosterTech Prep Applications, pp. 43-44 L2

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Key to Teaching StrategiesKey to Teaching Strategies

Level 1 activities should be appropriatefor students with learning difficulties.Level 2 activities should be within theability range of all students.Level 3 activities are designed for above-average students.ELL activities should be within the abilityrange of English Language Learners.

Cooperative Learning activitiesare designed for small group work.These strategies represent student prod-ucts that can be placed into a best-workportfolio.These strategies are useful in a blockscheduling format.

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The following multimedia resources are available from Glencoe.

Biology: The Dynamics of LifeCD-ROM

BioQuest: Body SystemsExploration: Bones: The Body’s SupportAnimation: Paired Skeletal MusclesAnimation: Sliding Filament Theory

Videodisc ProgramPaired Skeletal MusclesSliding Filament Theory

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http://www.carolina.com

Section

Structure and Functionof the Skin

Skin is composed of layers of thefour types of body tissues: epithelial,connective, muscle, and nervous.Recall that epithelial tissue is derivedfrom the ectodermal layer of theembryo and functions to cover sur-faces of the body. Connective tissue,which consists of both tough andflexible protein fibers, serves as a sortof organic glue, holding your bodytogether. Muscle tissues interact withhairs on the skin to respond to stimulisuch as cold and fright. Nervous tissuehelps us detect external stimuli, suchas pain or pressure. As you can see,skin is a flexible and responsive organ.

Skin is composed of two principallayers—the epidermis and dermis.Each layer performs a different func-tion in the body.

Epidermis: The outer layer of skin

The layer of skin that you see cov-ering your body is called the epider-mis. The epidermis is the outermostlayer of the skin, and is made up oftwo parts—an exterior and interiorportion. The exterior layer of theepidermis consists of 25 to 30 layersof dead, flattened cells that are continually being shed. Althoughdead, these cells still serve an impor-tant function as they contain a protein called keratin (KER uh tun).

34.1 SKIN: THE BODY’S PROTECTION 923

L ike all land animals, you live in a harsh, dry world. One ofthe many challenges you face

is maintaining a moist environmentinside your body. In addition, you mustregulate your internal body tempera-ture, keeping it within a certain range.Your skin helps you accomplish both ofthese tasks. Although it mayseem like just a wrapping onthe surface of your body,you’ll see that skin isactually a complex organthat performs a varietyof functions.

SECTION PREVIEW

ObjectivesCompare the makeupand functions of thedermis and epidermis.Recognize the role ofthe skin in respondingto external stimuli.Outline the healingprocess that takes placewhen the skin is injured.

Vocabularyepidermiskeratinmelanindermishair follicle

34.1 Skin: The Body’sProtection

OriginWORDWORD

epidermisFrom the Greekwords epi, meaning“on,” and derma,meaning “skin.”The epidermis covers other layersof skin.

The skin helps you lose orretain heat, depending onyour environment.

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Section 34.1

BIOLOGY: The Dynamics of Life SECTION FOCUS TRANSPARENCIES

Use with Chapter 34,Section 34.1

Look at the title of this transparency. How does the polyethylenecontainer in the picture satisfy these requirements?

Do you think that polyethylene would be a satisfactory substitutefor skin? Explain.

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SECTION FOCUS

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Transparency To Cover, Contain,and Protect81

PrepareKey ConceptsStudents look at how the skinfunctions to protect the body.

Planning■ Gather ink pads, fingernail

polish remover, cotton balls,index cards, and hand lensesfor MiniLab 34-1.

1 FocusBellringer Before presenting the lesson, display Section Focus Trans-parency 81 on the overhead pro-jector and have students answerthe accompanying questions.

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Assessment PlannerAssessment PlannerPortfolio Assessment

Portfolio, TWE, pp. 926, 931, 936BioLab, TWE, pp. 940-941

Performance AssessmentMiniLab, SE, pp. 925, 937BioLab, SE, pp. 940-941MiniLab, TWE, p. 925Assessment, TWE, pp. 932, 939Alternative Lab, TWE, pp. 924-925

Knowledge AssessmentAssessment, TWE, pp. 934, 938Section Assessment, SE, pp. 928, 934, 939Chapter Assessment, SE, pp. 943-945Problem-Solving Lab, TWE, pp. 926, 933,

936MiniLab, TWE, p. 937

Skill AssessmentAlternative Lab, TWE, pp. 924-925Assessment, TWE, pp. 927, 928

What You’ll Learn■ You will recognize the skin’s

role in protecting your body.■ You will identify the many

functions of your skeleton.■ You will classify the different

types of muscles in your body.

Why It’s ImportantYour skin, skeleton, and mus-cles work together to protect,support, and move your body.A knowledge of each systemhelps you understand how yourbody is able to accomplish sucha variety of activities.

Looking at Skin PatternsHave students examine the skinon their hands. What feature of your skin is so unique that itdistinguishes you from all otherpeople in the world? Lead aclass discussion of how finger-prints can be useful to hospitals,police investigators, and so on.

To find outmore about

skin, bones, and muscles, visitthe Glencoe Science Web Site. www.glencoe.com/sec/science

Protection, Support, and Locomotion34

GETTING STARTEDGETTING STARTED

ChapterChapter

Strong muscles and bonesallow a basketball player toleap above a defender, or atennis player to serve a ball at breakneck speed.

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Theme DevelopmentThe major themes of the chapterare systems and interactions.Various body structures are dis-cussed in relation to the systemsthey form. Interactions amongand within systems are alsoemphasized.

Chapter 34Chapter 34

MultipleLearningStyles

Look for the following logos for strategies that emphasize different learning modalities.

Kinesthetic Portfolio, pp. 926,931; Quick Demo, p. 927Visual-Spatial Building a Model,p. 930; Quick Demo, p. 931;

Project, p. 938Interpersonal Meeting Indivi-dual Needs, p. 932; Reteach,

p. 934; Activity, p. 934

Intrapersonal Tech Prep, p. 926; Meeting Individual Needs, p. 927Linguistic Biology Journal, p. 927; Cultural Diversity, p. 930;

Enrichment, p. 931; Portfolio, p. 936Logical-Mathematical Reteach,p. 928; Tech Prep, p. 933; Biology

Journal, p. 937

GETTING STARTED DEMOGETTING STARTED DEMO

Call students’ attention to thephotos of athletes on this pageand in the magazines theybring to class. Discuss howmuscle and skeletal shapes/sizes differ in the various typesof athletes.

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If time does not permit teach-ing the entire chapter, use theBioDigest at the end of theunit as an overview.

Internet Address Book

NoteInternet

addresses that you find usefulin the space below for quickreference.

Resource ManagerResource Manager

Section Focus Transparency 81and Master

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MiniLab 34-1MiniLab 34-1 Comparing

Examine Your Fingerprints Fingerprints play a major rolein any police investigation. Because a fingerprint is an individ-ual characteristic, extensive FBI fingerprint files are used foridentification in criminal cases.

Procedure! Press your thumb lightly on the surface of an ink pad.@ Roll your thumb from left to right across the corner of an

index card, then immediately lift your thumb straight upfrom the paper.

# Repeat the steps above for your other four fingers, plac-ing the prints in order across the card.

$ Examine your fingerprints with a magnifying lens, identi-fying the patterns in each by comparing them with thediagrams below.

% Compare your fingerprints with those of your classmates.

Analysis1. Are the fingerprint patterns on your five fingers all the same?2. Do any of your fingerprints show the same patterns as

those of a classmate?3. Why is a fingerprint a good way to identify a person?

Keratin helps protect the living celllayers underneath and contributes toskin’s elasticity.

The interior layer of the epidermiscontains living cells that continuallydivide to replace the dead cells. Someof these cells contain melanin, a pig-ment that colors the skin and pro-tects the cells from damage by solarradiation. As the newly formed cellsare pushed toward the skin’s surface,the nuclei degenerate and the cellsdie. Once they reach the outermostepidermal layer, the cells are shed.This entire process takes about 28days. Therefore, every four weeks, allcells of the epidermis are replaced bynew cells.

Look at your fingertips. The epi-dermis on the fingers and palms ofyour hands, and on the toes and solesof your feet, contains ridges andgrooves that are formed before birth.These epidermal ridges are impor-tant for gripping as they increasefriction. As shown in Figure 34.1,footprints, as well as fingerprints, areoften used to identify individuals aseach person’s pattern is unique. Makea set of your own fingerprints whiledoing the MiniLab on this page.

Dermis: The inner layer of skinThe second principal layer of the

skin is the dermis. The dermis is theinner, thicker portion of the skin.The thickness of the dermis varies indifferent parts of the body, depend-ing on the function of that part.

The dermis contains structuressuch as blood vessels, nerves, nerveendings, hair follicles, sweat glands,and oil glands. Why do some peoplehave dark skin while others are pale?Find out by reading the Inside Story.Some areas of your skin may belooser and more flexible than others.This is because different amounts offat lie underneath the dermis in dif-


Figure 34.1Babies’ footprints are recorded at birth to establishan identification record for them in the future.

Arch Whorl Loop Combination

PurposeStudents will observe, describe,and compare similarities and dif-ferences among fingerprint pat-terns to determine theuniqueness of such patterns.

Process Skillsobserve and infer

Safety Precautions Be sure students do not breathethe fingernail polish removerfumes. When this substance is inuse, the room should be well ven-tilated. Keep chemicals awayfrom open flames.

Teaching Strategies■ Students should use nail polishremover to clean the ink off theirfingers before washing them withsoap and water.

Expected ResultsEach finger has a unique finger-print and each individual has aunique set of fingerprints.

Analysis1. Although each finger has a

unique fingerprint, the gen-eral patterns may be the sameon different fingers.

2. It is possible that studentsmay share patterns, but notidentical fingerprints.

3. It is unique for each person.

Performance Have stu-dents design an experiment todetermine if the print patterns oftoes are unique to each individual.Use the Performance TaskAssessment List for Designing anExperiment in PASC, p. 23. L3

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AssessmentAssessment

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except on the epidermis of the finger-tips, palms, and soles of the feet,where they create parallel ridges thatfacilitate gripping.

Analysis1. What structures form the fingerprints

seen on fingers? The outer portion ofthe dermis has projections, or papillae,that form the epidermal ridges seen infingerprints.

2. What is the function of the oil glands

of the skin? Oil secreted by the glandskeeps hair from drying out and keepsthe skin soft and pliable.

3. How does sunlight affect the amountof melanin in skin? Sunlight causes anincreased production of melanin in skincells.

Skill Have students draw, label,and color human skin as seen under themicroscope. Students should place theirdrawings in their journals. Use thePerformance Task Assessment List forScientific Drawing in PASC, p. 55.

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925

Dermis

Subcutaneouslayer

Epidermis Sweat pore

Dead epidermis

Living epidermis

Touch receptor

Nerve

Fat tissue

ArteryVein

Muscle

Hair follicle

924 PROTECTION, SUPPORT, AND LOCOMOTION

The Skin

The skin is an organ because it consists of tissues joinedtogether to perform specific activities. It is the largest

organ of the body; the average adult’s skin covers one totwo square meters.

Critical Thinking Why does your skin get sweaty and oily?

Melanin in skin cells.

INSIDESSTORTORYY

INSIDE

Oil glands Most oil glandsare connected to hair follicles.Oil prevents hair from dryingout and keeps the skin soft andpliable. It also inhibits thegrowth of certain bacteria.

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Elasticity Theconnective tissue ofthe dermis containsmany elastic fibersthat allow the skinto return to its orig-inal shape afterbeing stretched.

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Hair Hair’s primary function isprotection of the skin from injuryand damaging solar rays. It alsoprovides an insulating layer of airjust above the surface of the skin.

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Sweat glandsSweat glands arelocated deep in thedermis and open upthrough pores ontothe surface of theskin. On average, aperson loses about900 mL of sweateach day.

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Melanin Differencesin skin color are dueto the amount of thepigment melanin pro-duced by the cells.Exposure to sunlightcauses an increase inmelanin production,and the skin becomesdarker.

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2 TeachPurposeStudents gain a further under-standing of how structures of theskin perform their functions.

Teaching Strategies■ Ask students to identify theprimary function of hair.■ Use the diagram to point outto students where pimples mayform. in blocked hair follicles

Visual Learning■ If you set up the bulletin board

display showing skin problems,challenge students to identifywhich skin structure isinvolved in each problemshown.

Critical ThinkingThe skin gets sweaty in order tocontrol its internal temperatureas evaporated sweat lowers bodytemperature. The skin secretesoil to keep from drying out.

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Alternative LabThe Structure of Skin

PurposeIn this lab, students will observe the struc-ture of human skin.PreparationYou may choose to view the slides yourself

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before giving them to students to view.Look for the structures named in the stepsbelow. Remind students to handle pre-pared slides with extreme caution.Materialsmicroscope slide of human skin, microscopeProcedureGive students the following directions.

1. View the human skin slide on lowpower. Focus first on the epidermis andswitch to high power.

2. Then switch back to low power andlocate the dermis of the skin. Switch tohigh power.

3. Find the following structures: hair folli-cle, hair shaft, sweat gland, blood ves-sels, fat deposits, oil gland, and elasticfibers.

4. Notice that the outer portion of thedermis has numerous projections, simi-lar to hills and valleys. These projec-tions, or papillae, form no pattern924

IINSIDENSIDESSTORTORYY

INSIDE MiniLab 34-1MiniLab 34-1


BioLab and MiniLab Work-sheets, p. 151

Basic Concepts Transparency61 and Master

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Scab

Blood clot

Scab New skin cells

Skin also plays a role in producingessential vitamins. When exposed toultraviolet light, skin cells producevitamin D, a nutrient that aids theabsorption of calcium into the blood-stream. Because an individual’s expo-sure to sunlight varies, daily intake ofvitamin D supplements is sometimesneeded to meet requirements.

Skin also serves as a protectivelayer to underlying tissues. It shieldsthe body from physical and chemicaldamage and from invasion bymicrobes. Cuts or other openings inthe skin surface allow bacteria toenter the body and so must berepaired quickly. Figure 34.3 showsthe stages involved in skin repair.


Figure 34.3Healing the dermisafter injury occursin a series of stages.

Blood flowsout of thewound untila clot forms.

AA

A scab soon develops, creatinga barrier between bacteria onthe skin and underlying tissues.

BB

New skin cells begin re-pairing the wound frombeneath. A scar may formif the wound is large.

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Skill Have students makea diagram outlining the processwhereby a skin injury is healed.

EnrichmentHave students conduct researchon artificial skin. Students shouldreport how artificial skin is madeand how its structure compareswith that of natural skin. L3

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Problem-Solving Lab 34-1Problem-Solving Lab 34-1 Recognizing Causeand Effect

ferent parts of your body. These fatdeposits help the body absorbimpact, retain heat, and store food.

Hair grows out of narrow cavitiesin the dermis called hair follicles,as shown in Figure 34.2. As hairfollicles develop, they are suppliedwith blood vessels and nerves andbecome attached to muscle tissue.Most hair follicles have an oil glandassociated with them. When oil anddead cells block the opening of thehair follicle, blackheads or pimplesmay form.

The skin’s vital functionsOne major function of skin is to

regulate your internal body temper-ature. Think about how your bodywarms up as you exercise. Whenyour body temperature rises, themany small blood vessels in the der-mis dilate, blood flow increases, andbody heat is lost by radiation. Thismechanism also works in reverse.When you are cold, the blood ves-sels in the skin constrict and heat is conserved.

Another noticeable thing thathappens to your skin as your bodyheats up is that it becomes wet.Glands in the dermis produce sweatin response to an increase in bodytemperature. As sweat evaporates,the body cools. This is because aswater changes state from liquid to vapor, heat is lost. Investigate further the role of skin in coolingthe body by carrying out theProblem-Solving Lab on this page.

Of course, anyone who has everstepped on a sharp object or beenburned by a hot pot handle knowsthat skin also functions as a senseorgan. Nerve cells in the dermisreceive stimuli from the externalenvironment and relay informationabout pressure, pain, and tempera-ture to the brain.

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Figure 34.2Photomicrographof a cross sectionof human skinwith hair follicleand hair.

How does your body respond to too much heat? As youexercise vigorously, you notice two things happening. One,you start to perspire. Two, your face becomes red. Both reac-tions are your body’s way of cooling off.

AnalysisAt right is a diagram

of the events that takeplace in your body with-out your having to tell it to respond to a rise ininternal temperature.

Thinking Critically1. What two systems (not

including the nervoussystem) work togetherto cool the body?

2. How is the braindirectly in control ofchanging body tem-perature?

3. If your body tempera-ture were too low,would perspiringincrease it? Explainyour answer.

4. Redraw and label the diagram to show the steps that would occur if your body temperature were too low.

Brain detects rise in blood temperature

Heat stimulatesnerves in

skin

Message sent toskin capillaries

Message sentto brain

Capillaries dilate

Message sentto sweat glands

Excess heat lostthrough skin

Perspiration occurs

Body cools

Exercise causes

body to heat up

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PurposeStudents will analyze the series ofevents that occur in the body asinternal body temperatureincreases.

Process Skillsthink critically, recognize causeand effect, concept map, applyconcepts, predict, sequence

Teaching Strategies■ Make sure that students arefamiliar with all the terms used inthe lab, including dilate and capil-laries. ■ Verify that the concept of per-spiring as a way of lowering bodytemperature is understood bystudents.■ This lab would be suitable forsmall cooperative groups.

Thinking Critically

1. skin (dermis and epidermis)and circulatory (blood capil-laries)

2. The brain is the structurethat gives the signal to thesweat glands (to producesweat) and to the capillaries(to dilate).

3. No, perspiring is a mecha-nism used for lowering bodytemperature.

4. Cold causes body tempera-ture to drop ⇒ brain detectsdrop in blood temperature ⇒message sent to blood capil-laries ⇒ capillaries constrict⇒ heat not lost from skin ⇒body warms.

Knowledge Ask studentsto explain why a person becomesflushed when he or she has a fever. What evidence do they have that body temperatureis controlled automatically andnot consciously? Use thePerformance Task AssessmentList for Formulating a Hypothe-sis in PASC, p. 21. L2

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Problem-Solving Lab 34-1Problem-Solving Lab 34-1

PortfolioPortfolio

Modeling Skin Structure Kinesthetic Have students use a variety of materials to create three-

dimensional models of the skin. Encouragestudents to use the illustrations found inthe Inside Story as a guide. Students shouldinclude labels that identify each structurein their models as well as its function.

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Acne TreatmentsIntrapersonal Ask students tosearch the Internet and teen maga-

zines to find various acne treatments.Have them record in their journals howthese treatments prevent or treat acne.P

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Quick DemoQuick Demo

Kinesthetic Ask studentsto examine and compare

the skin that covers variousparts of their bodies anddescribe whether the skin isthe same in all places. Likelyresponses will state that, in dif-ferent parts of the body, skinhas different thicknesses, variesin moisture, is tight or loose,and is either covered with hairor hairless.

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MEETING INDIVIDUAL NEEDS MEETING INDIVIDUAL NEEDS

Gifted Intrapersonal Have gifted studentsresearch the current treatments

being used by regional burn centers forpeople with life-threatening third-degreeburns. This research can be done in thelibrary or on the Internet.

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BIOLOGY JOURNAL BIOLOGY JOURNAL

Writing a Story Linguistic Have students write astory about skin injury and healing

from the viewpoint of the skin. Studentsshould include the steps outlined in Figure34.3 in their stories.

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VIDEODISCThe Infinite Voyage:Miracles by Design, Burn

Patients and Artificial Skin (Ch.5) 8 min.

!7U`H"

3 AssessCheck for UnderstandingOn the chalkboard, list the struc-tures of the skin and ask studentsto copy the list. Have studentsidentify the function of eachstructure. L1

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Section AssessmentSection Assessment

Understanding Main Ideas1. Which skin structures are damaged from a third-

degree burn?2. How does skin help control body temperature?3. How do pimples form?4. What happens to the dermal blood vessels when

you are cold? Hot?

Thinking Critically5. Why do some areas of your body contain more

fat deposits than others?

6. Sequencing Outline the steps that occur whena cut in the skin heals. For more help, refer toOrganizing Information in the Skill Handbook.

SKILL REVIEWSKILL REVIEW

Skin Injury andHealing

If you’ve ever had amild scrape, you knowthat it doesn’t take longfor the wound to heal.When the epidermis sus-tains a mild injury, suchas a scrape, the deepestlayer of epidermal cellsdivide to help fill in thegap left by the abrasion.If, however, the injuryextends into the dermis,where blood vessels arefound, bleeding usuallyoccurs. The skin thengoes through a series ofstages to heal the dam-aged tissue. The first

reaction of the body is to restore thecontinuity of the skin, that is, to closethe break. Blood flowing from thewound soon clots. The wound is thenclosed by the formation of a scab,which prevents bacteria from enter-ing the body. Dilated blood vesselsthen allow infection-fighting whiteblood cells to migrate to the woundsite. Soon after, skin cells beneath thescab begin to multiply and fill in thegap. Eventually, the scab falls off toexpose newly formed skin. If a woundis large, high amounts of dense con-nective tissue fibers used to close thewound may leave a scar.

Have you ever suffered a painfulburn? Burns can result from exposureto the sun or contact with chemicalsor hot objects. Burns are ratedaccording to their severity.

First-degree burns involve thedeath of epidermal cells and are char-acterized by redness and mild pain.Most people have received a first-degree burn at one time or another,usually as the result of sunbathing.Second-degree burns involve damageto skin cells of the dermis and canresult in blistering and scarring. Themost severe burns are third-degreeburns, which destroy both the epi-dermis and the dermis. With thistype of burn, skin function is lost,and skin grafts may be required toreplace lost skin. In some cases,healthy skin can be removed fromanother area of the patient’s body andtransplanted to a burned area.

As people get older, their skinchanges. It becomes drier as glandsdecrease their production of lubricat-ing skin oils—a mixture of fats, cho-lesterol, proteins and inorganic salts.As shown in Figure 34.4, wrinklesmay appear as the elasticity of theskin decreases. Although thesechanges are natural, they can beaccelerated by prolonged exposure toultraviolet rays from the sun.Sunblock, used regularly, can preventmuch of the damage caused by thesun’s rays.


Figure 34.4As people age, theirskin loses its elastic-ity and begins towrinkle.

928

ReteachLogical-Mathematical Havestudents organize the fol-

lowing information about skinthicknesses in a table. The thick-ness of the epidermis on the backis 0.25 mm, on the face and scalp0.12 mm, on the palm 0.5 mm.The thickness of the dermis onthe back is 3.75 mm, on the faceand scalp 1.6 mm, and on thepalm 1.0 mm. Discuss why skinthickness varies in different partsof the body by relating this phe-nomenon to the function of theskin in each area.

ExtensionEncourage interested stu-dents to research what sort

of special training dermatologistsreceive in medical school. Whatkinds of skin problems do theytreat? skin cancer, burns, rashes,acne, among others

Skill Ask students to writea paragraph listing the functionsof the skin as they relate to skinstructures.

4 CloseDiscussionDiscuss the relationship betweenthe structures of the skin and theskin’s functions. Relate the pres-ence of sweat glands, hair, oilglands, nerves, and blood vesselsto the functions of skin. Ask stu-dents what problems a burn vic-tim faces. infection, fluid loss

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Section AssessmentSection AssessmentSection Assessment1. All of the structures found in both the

epidermis and the dermis are destroyedin a third-degree burn.

2. by producing sweat and by constrictionand dilation of skin capillaries

3. Pimples result from bacteria growing inthe hair follicle when oil and dead cellsblock the follicle’s opening to the skin’ssurface.

4. The blood vessels constrict when you arecold and dilate when you are hot.

5. Fat deposits can serve to protect organsin particular areas of the body. Thesedeposits are also used to store energy.

6. (1) formation of blood clot, (2) blood ves-sels dilate and infection-fighting bloodcells rush to the wound, (3) epidermalcells divide to fill in the wound


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Section

34.2 BONES: THE BODY’S SUPPORT 929

Skeletal SystemStructure

The adult human skeleton con-tains about 206 bones. Its two mainparts are shown in Figure 34.5 onthe next page. The axial skeletonincludes the skull and the bones that support it, such as the vertebralcolumn, the ribs, and the sternum.The appendicular skeleton (a penDIHK yuh lur) includes the bones ofthe arms and legs and structuresassociated with them, such as theshoulder and hip bones, wrists,ankles, fingers, toes and so on.

Joints: Where bones meetNext time you open a door, notice

how it is connected to the doorframe. A metal joint positionedwhere the door and frame meetallows the door to move easily backand forth. In vertebrates, joints arefound where two or more bonesmeet. Most joints facilitate the move-ment of bones in relation to oneanother. The joints of the skull, onthe other hand, are fixed, as thebones of the skull don’t move. Theseimmovable joints are actually heldtogether by the intergrowth of bone,or by fibrous cartilage.

Would you believe that you hadmore bones when you wereborn than you have now?

That’s because some of your bones havegrown together since then. Your head,for example, had soft spots when youwere an infant. It feels solid nowbecause the soft membranes were grad-ually replaced by bone. Remodeling ofthe skeleton occurs throughout life. In fact, your skeletonhasn’t completelyformed yet. You willnot have a solid, fusedskeleton until aboutage 25.

SECTION PREVIEW

ObjectivesIdentify the structureand functions of theskeleton.Compare the differenttypes of movable joints.Recognize how bone isformed.

Vocabularyaxial skeletonappendicular skeletonjointligamentbursatendoncompact bonespongy boneosteoblastosteocytered marrowyellow marrow

34.2 Bones: The Body’sSupport

As a baby develops in the uterus,its bones fuse together.

Section 34.2

PrepareKey ConceptsStudents become acquainted withthe structure of bones and theirfunctions.

Planning■ Obtain X rays for the Quick

Demo.■ Borrow a human skeleton for

the Quick Demo and MeetingIndividual Needs.

■ Save two toilet paper tubes forBuilding a Model.

■ Soak a chicken bone in vinegaror HCl for the Quick Demo.

■ Have beef bones cut by abutcher for the Quick Demo.


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929



Describe the range of motion that is possible in each object pictured.

Identify a part of the human skeleton that can move like each ofthe objects.

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CD-ROMBiology: The Dynamics of LifeBioQuest: Body Systems

Disc 1-5Exploration: Bones: The Body’s Support Disc 5

Resource ManagerResource ManagerSection Focus Transparency 82 and

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Forcible twisting of a joint, called asprain, can result in injury to the bur-sae, ligaments, or tendons. A sprainmost often occurs at joints with largeranges of motion such as the wrist,ankle, and knee.

Besides injury, joints are also sub-ject to disease. One common joint

disease is arthritis, an inflammationof the joints. It can be caused byinfections, aging, or injury. One kindof arthritis results in bone spurs, orsplinters of bone, inside the joints.Such arthritis is especially painful,and often limits the patient’s abilityto move his or her joints.


Figure 34.6Body movements are made possible by joints thatallow bones to move in several different directions.

Ball-and-socket joints allow rotational movement.The joints of the hips and shoulders are ball-and-socket joints; they allow you to swing your armsand legs around in a circular motion.

AA Pivot joints allow bones to twist around eachother. One of the joints in your elbow is a pivotjoint. It allows you to twist your lower armaround.

BB

Hinge joints are found in the elbows, knees, fingers, and toes. They allow back-and-forthmovement like that of a door hinge.

CC Gliding joints, found in the wrists and ankles,allow bones to slide past each other.

DD

931

EnrichmentLinguistic Osteoporosis is acondition in which the

bones become porous and thindue to reduced bone mass.Factors that increase the risk ofosteoporosis include being awoman, being Caucasian, chroniclow calcium intake, lack of exer-cise, being underweight, andsmoking. One treatment forosteoporosis is estrogen replace-ment therapy, which reduces fur-ther bone loss. However, thistherapy increases the risk ofendometrial cancer, abnormalbleeding, and other medical com-plications. Some scientists suggestthat any activity involving themuscles working against gravitymay increase bone strength inpostmenopausal women andreduce bone loss. Have studentsresearch the pros and cons ofestrogen therapy and write a briefreport of their findings. L3

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Concept DevelopmentHave students use a medical dic-tionary to find out what is meantby the terms slipped disk or herni-ated disk. Have students find outthe causes of these problems andreport their findings to the class.L2

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Skeletalsystem

206bones

Axialskeleton 80

Appendicularskeleton

126

Skull andassociated

bones29

Thoraciccage 25

Upperlimbs 60

Pelvicgirdle 2

Lowerlimbs 60

Pectoralgirdles 4

Vertebralcolumn 26

Skull (22)

814

CraniumFace

Associatedbones (7)

6

1

EarbonesHyoid

1Sternum

24Vertebrae

28

10

28Phalanges

2Femur

2Patella

2Tibia

2Fibula

28Phalanges

14Tarsal bone

1Sacrum

1Coccyx

24Ribs

Hip bone(coxa)

Carpalbones

Metacarpalbones

10Metatarsalbone

2Clavicle

2Scapula

2Humerus

2Radius

2Ulna

16

10

2

Joints are often held together andenclosed by ligaments. A ligament isa tough band of connective tissue thatattaches one bone to another. Jointswith large ranges of motion, such asthe knee, typically have more liga-ments surrounding them. In movablejoints, the ends of bones are coveredwith a layer of cartilage, which allowsfor smooth movement between the

bones. In addition, joints such asthose of the shoulder and knee havefluid-filled sacs called bursae locatedbetween the bones. The bursae act to absorb shock and keep bones from rubbing against each other.Tendons, which are thick bands ofconnective tissue, attach muscles tobones. Figure 34.6 shows the differ-ent movable joints in the skeleton.


Figure 34.5The axial skeleton includes the bonesof the head, back, and chest. Bones inthe appendicular skeleton are relatedto movement of the limbs.

OriginWORDWORD

arthritisFrom the Greekwords arthron,meaning “joint,”and itis, meaning“swelling disease.”Arthritis is aswelling disease ofthe joints.

930

Visual LearningHave students examine Figure34.5. Ask: To which skeletalgroup do the phalanges belong?appendicular

Building a ModelVisual-Spatial To demon-strate the strength of hollow

bones, have students balance aheavy book on the open ends oftwo toilet paper tubes placed sideby side.

Revealing MisconceptionsMany students believe that maleshave fewer ribs than females.Explain to students that malesand females have an equal num-ber of ribs.

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Tying to PreviousKnowledgeCompare the anatomy of thefront limbs of a frog, bird, cat,whale, and bat with that of thehuman arm. Compare the num-ber, shapes, and arrangements ofbones.


Project X rays or hang them inwindows on the day that youbegin discussing the skeleton.Identify the bones shown ineach X ray and the types ofinformation X rays can revealabout bones.

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Visual-SpatialDemineralize a chicken

bone by soaking it in vinegar or10% HCl for several days. (Forpreparation instructions, seepage 40T of the Teacher Guide.)Have students compare a regu-lar bone to the demineralizedbone.

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Point out the differencesbetween a male and femalepelvis using skeletal diagrams.P

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2 Teach

Cultural Diversity

Human Skeletal VariationLinguistic Variation exists in humanbody form, especially within the skele-

tal system. Differences in skeletal morphol-ogy are related to the geographical originsof populations. For example, a leaner bodyform is often observed in people who live inarid regions where greater skin-surface area

in proportion to body weight facilitates heatloss. A stockier build is more adaptive forinhabitants of cold areas. Differences in bodyform and skin color have been used as a justification for racism. Have students writeshort essays about how their attitudes onracism have been affected by an understand-ing of human variation. L2

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PortfolioPortfolio

Joint Movement Kinesthetic Have students gatherexamples of everyday objects that

model the movement of each type of joint.Have them describe on index cards thetype of movement each object allows andthe type of joint that allows this move-ment in the body.

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Marfan’s Syndrome Have advanced students report on Mar-fan’s syndrome, which affects connectivetissue, bones, muscles, and ligaments. It ispossible that Abraham Lincoln was mildlyafflicted with this syndrome. Have stu-dents explain how this syndrome affectsnormal functioning of the musculoskeletalsystem.

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Critical Thinking/ProblemSolving, p. 34

Concept Mapping, p. 34Basic Concepts Transparency

62 and Master

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Bone growthYour bones grow in both length

and diameter. Growth in lengthoccurs at the ends of bones in carti-lage plates. Growth in diameteroccurs on the outer surface of thebone. The increased production ofsex hormones during your teen yearscauses the osteoblasts to divide morerapidly, resulting in a growth spurt.By age 20, about 98 percent of yourskeleton growth will be completed.However, these same hormones willalso cause the growth centers at theends of your bones to degenerate. Asthese cells die, your growth will slow.After growth stops, bone-formingcells are involved mainly in repairand maintenance of bone. Learnmore about how bones age by per-forming the Problem-Solving Lab onthis page.

Skeletal SystemFunctions

The primary function of yourskeleton is to provide a frameworkfor the tissues of your body. Theskeleton also protects your internalorgans, including your heart, lungs,and brain.

The arrangement of the humanskeleton allows for efficient bodymovement. Muscles that move thebody need firm points of attachmentto pull against so they can workeffectively. The skeleton providesthese attachment points.

Bones also produce blood cells.Red marrow—found in the humerus,femur, sternum, ribs, vertebrae, andpelvis—is the production site for redblood cells, white blood cells, andcell fragments involved in blood clot-ting. Yellow marrow, found in manyother bones, consists of stored fat asshown in Figure 34.8.


Figure 34.8Bones can storefat for use intimes of need.

Problem-Solving Lab 34-2Problem-Solving Lab 34-2 Making and UsingTables

How does bone density differ between the sexes? Bonehas a certain compactness or strength that can be measuredin terms of the bone’s mineral density. The higher the densityof bone, the stronger it is. The lower the density of bone, theweaker it is.

AnalysisExamine the following

average values for bone density of males and females at different ages. The data are for the upper femur where it fits into the hip.

Thinking Critically1. What is the general

trend for bone density as a person ages?

2. Between the ages of 20 and 50, what percentage of bone density do females lose compared with males? Whatpercentage is lost between the ages of 50 and 80 foreither sex?

3. Which sex shows the greater change in bone density as it ages? Between which ages does the greatest changeoccur?

4. The hormone in females that prevents bone density fromdecreasing begins to diminish at the age of 50. Does thiscorrelate with the changes in bone density reported in the chart? Use specific numbers in your answer.

Age MaleFemale

20

30

40

50

60

70

80

0.979

0.936

0.894

0.851

0.809

0.766

0.724

0.895

0.886

0.850

0.797

0.733

0.667

0.607

Average Bone Mineral Density

933

Purpose Students will comparebone density data for

males and females at various ages.

Process Skillsmake and use tables, use num-bers, think critically, interpretdata, compare and contrast

Teaching Strategies■ Review the procedure for cal-culating percentages. ■ Remind students that prior tocalculating all values called for inthe Thinking Critically section,the amount of final bone densityfor an age group must be sub-tracted from the original bonedensity to arrive at the amount ofbone density lost. Use amount ofbone density lost compared withoriginal bone density to calculatepercent of bone density lost.

Example: Find the percentbone density lost for femalesbetween the ages of 20 and 50.

Step 1: 0.895– 0.797 = 0.098Step 2: 0.895/ 0.098 = 100/x 0.895x = 9.8, x = 10.9%

Thinking Critically1. Bone density decreases with

age regardless of sex. 2. females from 20-50 = 10.9%

males from 20-50 = 13.0%; females from 50-80 = 23.8%males from 50-80 = 14.9%

3. females, from age 50-804. Yes, from ages 20-50 a

decrease in bone density ofonly 10.9% is measured forfemales, but from 50-80, thedecrease is 23.8%.

Knowledge Have studentsresearch the benefits of exerciseon bone density. Challenge themto correlate their findings withthe need for exercise by theelderly. Students should summa-rize their research in their jour-nals. Use the Performance TaskAssessment List for Writing inScience in PASC, p. 87. L3

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Spongy bone

Cartilage

Bloodvessel

Marrow cavity

Spongybone

Capillary Osteonsystems

Artery VeinBone cell

Osteon system

Compact bone

Membrane

Compact and spongy bone

Although bones may appear uni-form, they are actually composed oftwo different types of bone tissue, asshown in Figure 34.7. Surroundingevery bone is a layer of hard bone, orcompact bone. Running the lengthof compact bone are tubular struc-tures known as osteon systems, asshown in Figure 34.7. Compactbone is made up of repeating units ofosteon systems. Living bone cells, orosteocytes, receive oxygen and nutri-ents from small blood vessels runningwithin the osteon systems. Nerves inthe canals conduct impulses to andfrom each bone cell. Compact bonesurrounds less dense bone known asspongy bone, so called because it isfilled with many holes and spaces,like those in a sponge.

Formation of BoneThe skeleton of a vertebrate

embryo is made of cartilage. By theninth week of human development,bone begins to replace cartilage.Blood vessels penetrate the mem-brane covering the cartilage andstimulate its cells to become potentialbone cells called osteoblasts (AHS teeoh blastz). These potential bone cellssecrete a protein called collagen inwhich minerals in the bloodstreambegin to be deposited. The depositionof calcium salts and other ions hard-ens the newly formed bone cells, nowcalled osteocytes. The adult skeletonis almost all bone, with cartilagefound only in places where flexibilityis needed—regions such as the nosetip, external ears, discs between ver-tebrae, and movable joint linings.


Figure 34.7A bone has several components, including compact bone,spongy bone, and osteon systems. The osteon systemscontain blood vessels that nourish bone cells and nervetissues that conduct impulses to and from each cell.

OriginWORDWORD

osteoblastFrom the Greekwords osteon, mean-ing “bone,” andblastos, meaning“sprout.” Osteo-blasts are cells thathelp create bone by facilitating thedeposit of minerals.

Bone cell

932

Using Science TermsDiscuss the derivation of theword osteoporosis with students.Ask students to find other termsin the chapter that make use ofthe prefix osteo-. Ask them toexplain how the prefix relates tothe meaning of each term.

Performance Have stu-dents make a poster diagrammingthe process of bone formation.P

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Have a beef bone cut in halflongitudinally and anotherone cut crosswise. Point outthe compact bone, spongybone, and marrow. If thebone is fresh, you can pointout the membrane that coversthe bone.

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Visually/Hearing Impaired Interpersonal Have visually impairedand hearing impaired students work

with other students to review the namesand functions of various bones of thebody. For visually impaired students, havean articulated human skeleton availablefor this activity.

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Sports InjuriesLogical-Mathematical Have an ath-letic trainer, or students in athletic

training in the high school, speak to the class about sports injuries. Students can thenprepare an analysis of possible ways to pre-vent some of the sports injuries.

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VIDEODISCSTV: Human Body Vol. 2Bone Tissue,

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!7S|.&"Spongy and Compact Bone

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Exercise Programs: The Good, the Bad (Ch. 3) 3 min.

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Understanding Main Ideas1. Distinguish between the appendicular skeleton

and the axial skeleton.2. List the four main kinds of movable joints and

provide an example of each.3. In what way do bones change as a person ages?4. How is compact bone structurally different from

spongy bone?

Thinking Critically5. Why would it be impossible for bones to grow

from within?

6. Sequencing Outline the steps involved in boneformation—from cartilage to bone. For morehelp, refer to Organizing Information in the SkillHandbook.


Figure 34.9The X ray on the leftshows a leg bonethat has completelyfractured. The X rayon the right showsthe bone (with asupporting rod) afterit has healed. Thearrow indicates thearea where the breakhealed.

Bones store mineralsFinally, your bones serve as store-

houses for minerals, including cal-cium and phosphates. Calcium isneeded to form strong, healthybones and is therefore an importantpart of your diet. Sources of calciuminclude milk, yogurt, cheese, lettuce,spinach, and other assorted leafyvegetables.

Bone injury and diseaseBones tend to become more brittle

as their composition changes with age. For example, a disease calledosteoporosis (ahs tee oh puh ROH sus)

involves a loss of bone volume andmineral content, causing the bones tobecome more porous and brittle.Osteoporosis is most common inolder women because they producelesser amounts of estrogen—a hor-mone that aids in bone formation.

When bones are broken, as shownby the X ray images in Figure 34.9,a doctor moves them back into posi-tion and immobilizes them with acast or splint until the bone tissueregrows. Read more about the use of X rays in the diagnosis of brokenbones in the Physics Connection at theend of this chapter.

934

3 AssessCheck for UnderstandingHave students fill in the names ofthe bones and label an example ofeach of the major types of jointson a diagram of the skeleton.

ReteachInterpersonal Have studentsmake flash cards containing

the names of bones. On theopposite side of each card, havestudents describe where eachbone is located and identify itscommon name. Have studentswork in pairs to review the infor-mation on the flash cards.

ExtensionHave students conduct researchon the various types of arthritisand their causes and treatments.Have students construct a tableof their findings.

Knowledge Provide stu-dents with an outline showing thebones of the human skeleton.Have students create a color keyto show which bones make up theappendicular skeleton and whichmake up the axial skeleton

4 CloseActivity

Interpersonal Play bone andbone anatomy Password.

Divide the class into groups of two. Have one partner try toget the other to say a certainword by giving other one-wordclues. For example, if the pass-word were “skeleton,” the cluesmight include “bones,” “sup-port,” and so on. After they guessthe word, switch players.

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Section AssessmentSection AssessmentSection Assessment1. The axial skeleton includes the skull and

the bones that support it. The appendicu-lar skeleton includes the bones associatedwith the appendages.

2. ball-and-socket, shoulder or hip; pivotjoint, elbow; hinge joint, elbow, knees,fingers and toes; gliding, wrists andankles

3. Bones become more brittle with age.

4. Compact bone is made up of osteon sys-tems. Spongy bone is filled with holes.

5. The inflexible structure of compact bonewould not allow growth from the inside.

6. (1) embryo skeleton is cartilage; (2) bonebegins to replace cartilage—osteoblastssecrete a material in which calcium saltsand other ions are deposited and hardento form bone.

Skeletalmuscle fiber

Nucleus

Striation

Section

Three Types of MusclesNearly half of your body mass is

muscle. A muscle consists of groupsof fibers bound together. Almost allof the muscle fibers you will ever

34.3 MUSCLES FOR LOCOMOTION 935

Have you seen the Olympicgames on television?Think about the differ-

ent athletes involved in thegames. You may be able to tellwhat sports some of them par-ticipate in just by looking attheir body shapes. For example,swimmers and ice skaters have dif-ferent shapes because ice skaters developstrong leg muscles over many months oftraining, whereas swimmers developlarger shoulder muscles.

SECTION PREVIEW

ObjectivesClassify the three typesof muscles.Analyze the structureof a myofibril.Interpret the sliding filament theory.

Vocabularysmooth muscleinvoluntary musclecardiac muscleskeletal musclevoluntary musclemyofibrilmyosinactinsarcomeresliding filament theory

34.3 Muscles for Locomotion

A swimmer has well-developed shoulder muscles

have were present at birth. Figure 34.10 shows the three

main kinds of muscles in your body. One type of tissue, smoothmuscle, is found in the walls of your

Figure 34.10Muscles are undereither voluntary orinvoluntary controland differ in theirstructure and appearance.

Smooth muscle fibers areunder involuntary control andappear spindle-shaped.

AA Cardiac muscle fibers, whichare also under involuntarycontrol, appear striated orstriped when magnified.

BB Skeletal muscle fibers, while also striated, are under voluntary control.

CC

Magnification: 4500�

Cardiacmusclefiber

Striation

Nucleus

Magnification: 27 000� Magnification: 12 600�

Smoothmusclefiber

Nucleus

935

Section 34.3

PrepareKey ConceptsStudents learn to distinguishamong the three types of mus-cles. Emphasis is placed on thestructure and function of skeletalmuscle and the current sliding fil-ament theory of muscle contrac-tion.

Planning■ Obtain chicken feet and wings

for the Quick Demo.


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How would the shape of this object change if the lower springtightened? What would happen if the upper spring tightenedinstead?

Where on your body is an apparatus similar to the one shown?What takes the place of a spring?

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Heart Muscle,Magnified 100x

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Look at Muscle Contraction Muscle fibers are composed of a number of small functional units called sarcomeres.Sarcomeres, in turn, are composed of protein filaments calledactin and myosin. The sliding action of these filaments in relation to one another results in muscle contraction.

Procedure! Look at Diagrams A and B. Diagram A shows a sarcomere

in a relaxed muscle. Diagram B shows a sarcomere in aflexed muscle.

@ Using a centimeter ruler, measure and record the lengthof a: sarcomere, a myosin filament, and an actin filamentin diagram A. Record your data in a table.

# Repeat step 2 for Diagram B.

Analysis 1. When a muscle contracts, do actin or myosin filaments

shorten? Use specific data from your model to supportyour answer.

2. How does the sarcomere shorten when the parts thatmake it up don’t shorten?

MiniLab 34-2MiniLab 34-2 Interpretinglong fused muscle cells. Each fiber is made up of smaller units calledmyofibrils (mi oh FIBE rulz). Myo-fibrils are themselves composed ofeven smaller protein filaments thatcan be either thick or thin. Thethicker filaments are made of theprotein myosin, and the thinner fila-ments are made of the protein actin.The arrangement of myosin andactin gives skeletal muscle its striated,or striped, appearance. Each myofi-bril can be divided into sectionscalled sarcomeres (SAR kuh meerz),the functional units of muscle. Howdo nerves signal muscles to contract?Find out in the Inside Story on thenext page.

The sliding filament theory cur-rently offers the best explanation forhow muscle contraction occurs. Thesliding filament theory states that,when signaled, the actin filamentswithin the sarcomere slide towardone another, shortening the sarcom-ere and causing the muscle to con-tract. The myosin filaments, on theother hand, do not move. Learnmore about the sliding filament the-ory in the MiniLab on this page.

Muscle Strength and Exercise

How can you increase the strengthof your muscles? Muscle strengthdoes not depend on the number offibers in a muscle. It has beenshown that this number is basicallyfixed before you are born. Rather,muscle strength depends on thethickness of the fibers and on howmany of them contract at one time.Regular exercise stresses musclefibers slightly; to compensate forthis added workload, the fibersincrease in diameter.

Recall that ATP is produced dur-ing cellular respiration. Muscle cells

are continually supplied with ATPfrom both aerobic and anaerobicprocesses. However, the aerobic res-piration process dominates whenadequate oxygen is delivered to mus-cle cells, as when a muscle is at restor during moderate activity. Whenan adequate supply of oxygen isunavailable, such as during vigorousactivity, anaerobic respiration—specifically the process of lactic acidfermentation—becomes the primarysource of ATP production.


BB

AAActin

Myosin

OriginWORDWORD

myofibrilFrom the Greekwords mys, meaning“muscle,” and fib-rilla, meaning “smallfiber.” A myofibril is a small part of amuscle fiber.

How is rigor mortis used to estimatetime of death? Rigor mortis is thestiffening of both voluntary andinvoluntary muscles due to lack ofATP after death. Stiffening devel-ops about an hour or two afterdeath, and usually proceedsfrom the upper body to thelower body. Rigor mortis affectsthe face area first, the neck, chest,and arms next, and the legs last.Stiffening gradually subsides in thesame order it develops, disappearingcompletely after 24 to 36 hours.

AnalysisCoroners determine a victim’s time of death by examin-

ing body tissues under a microscope and observing thedegree of rigor mortis.

Thinking CriticallyA murder victim is found with relaxed face muscles, but a

stiff upper and lower body. How long might it have beensince the crime was committed?

Problem-Solving Lab 34-3Problem-Solving Lab 34-3 Drawing a Conclusioninternal organs and blood vessels.Smooth muscle is made up of sheets ofcells that are ideally shaped to form alining for organs such as the digestivetract and the reproductive tract. Themost common function of smoothmuscle is to squeeze, exerting pressureon the space inside the tube or organ itsurrounds in order to move materialthrough it. Because contractions of smooth muscle are not under conscious control, smooth muscle isconsidered an involuntary muscle.

Another type of involuntary muscleis the cardiac muscle, which makesup your heart. Cardiac muscle fibersare interconnected and form a net-work that helps the heart muscle con-tract efficiently. Cardiac muscle isfound only in the heart and is adaptedto generate and conduct electricalimpulses necessary for its rhythmiccontraction. The third type of muscletissue, skeletal muscle, is the typethat is attached to and moves yourbones. The majority of the musclesin your body are skeletal muscles,and, as you know, you can controltheir contractions. A muscle thatcontracts under conscious control iscalled a voluntary muscle. Find outhow coroners use muscle tissue sam-ples to determine a victim’s time ofdeath in the Problem-Solving Lab onthis page.

Skeletal MuscleContraction

Whether you are playing tennis,pushing a lawn mower, or writing,your muscles are contracting as theyperform the action. Figure 34.11shows the movement of the lower armas controlled by opposing muscles inthe upper arm. The majority of skele-tal muscles work in opposing pairs.

Muscle tissue is made up of musclefibers, which are actually just very


Body tissue showingrigor mortis

a

Relaxedbiceps

Contractingtriceps

Contractingbiceps

Relaxedtriceps

b

View an animationof muscle contraction inthe Presentation Builder ofthe Interactive CD-ROM.

CD-ROMFigure 34.11When the biceps muscle contracts,the lower arm is moved upward (a).When the triceps muscle on the backof the upper arm contracts, thelower arm moves downward (b).

Magnification:1500�

936

PurposeStudents will conclude how rigormortis is used to estimate time ofdeath.

Process Skillsanalyze, draw a conclusion

BackgroundWhen a person dies, the respira-tory and circulatory systems thatobtain and deliver oxygen to themuscles stop functioning. As aresult, the muscles do not receiveATP and they stiffen. Scientistsbelieve that stiffening rates arerelated to muscle fiber length,shorter fibers stiffening beforelonger ones. Full rigor mortistakes about 10-12 hours to set in.

Teaching Strategies■ Draw an outline of a humanbody on the chalkboard. On thediagram, trace the path of thestiffening of muscles in the bodythat indicates the progression ofrigor mortis.

Thinking CriticallyAccept all answers in the range of12-16 hours.

Knowledge Have students list the order and time frame inwhich rigor mortis subsides in thebody. Use the Performance TaskAssessment List for Events Chainin PASC, p. 91. L2

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Obtain some chicken feetfrom a butcher. Cut the upperend so that the tendons arefree. Pull on each tendon todemonstrate the movement ofthe toes. Use a chicken wing todemonstrate muscle pairing inthe same manner.

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Learning Disabled/EnglishLanguage Learners

Linguistic Have students who arehaving difficulty make flash cards

that show an anatomical term on one sideof the card and its meaning and locationon the other side. Have students work inpairs to review the cards.

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Evaluating Exercise ProgramsLogical-Mathematical Have stu-dents evaluate their own exercise

program in their journal. The AmericanHeart Association recommends a mini-mum of 30 minutes of moderate activityper day.

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PortfolioPortfolio

Sports Medicine Linguistic Ask students to prepareand conduct an interview with a

person who works in the field of sportsmedicine or in physical education.Students should include questions on thetype of training the specialists have andhow their programs relate to muscle fit-ness.

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CD-ROMBiology: The Dynamics of LifeAnimation: Paired Skeletal Muscles

Animation: Sliding Filament Theory Disc 5

VIDEODISCBiology: The Dynamicsof Life

Sliding Filament Theory (Ch. 30)Disc 2, Side 1, 67 sec.

!:,Å"

937

Purpose Students will measure the lengthof a sarcomere during musclerelaxation and contraction.

Process Skillsacquire information, apply con-cepts, collect data, compare andcontrast, formulate models, inter-pret data, measure in SI, predict

Teaching Strategies■ Provide students with rulers.■ Review vocabulary terms priorto the start of this activity.

Expected ResultsActin filaments slide over myosinfilaments resulting in shorteningof sarcomeres during contraction.

Analysis1. Students will learn that actin

and myosin do not change inlength.

2. Actin filaments slide overmyosin filaments, shorteningthe sarcomere.

Knowledge Using the dia-gram of relaxed muscle, have stu-dents explain why skeletal musclehas a striated appearance whenviewed under the microscope.Provide students with a slide ofstriated muscle tissue to verifytheir explanations. Use thePerformance Task AssessmentList for Making Observations andInferences in PASC, p. 17. L2

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MiniLab 34-2MiniLab 34-2

Paired Skeletal Muscles (Ch. 29)Disc 2, Side 1, 22 sec.

!9á~"

Think about what happens whenyou are running in gym class or around the track at school. Figure 34.12A illustrates how anathlete’s need for oxygen changes as the intensity of his or her work-out increases. At some point, yourmuscles are not able to get oxygenfast enough to sustain aerobic respiration and produce adequateATP. Thus, the amount of availableATP becomes limited. For yourmuscle cells to get the energy theyneed, they must rely on anaerobicrespiration as well. Figure 34.12Bindicates how, at a certain intensity,the body shifts from aerobic respi-ration to the anaerobic process of lactic acid fermentation for itsenergy needs.

During exercise, lactic acid buildsup in muscle cells. As the excesslactic acid is passed into the blood-stream, the blood becomes moreacidic, rapid breathing is stimu-lated, and cramping can occur. Asyou catch your breath followingexercise, adequate amounts of oxy-gen are supplied to your musclesand lactic acid is broken down.Regular exercise can result inimproved performance of muscles.Do the BioLab at the end of thechapter to find out how musclefatigue affects the amount of exer-cise your muscles can accomplish.



Understanding Main Ideas1. Compare the structure and functions of the three

main types of muscles.2. Summarize the sliding filament theory of muscle

contraction.3. How can exercise change muscle strength? How

can it change muscle function?4. What, for the most part, determines muscle

strength?

Thinking Critically5. Why would a disease that causes paralysis of

smooth muscles be life threatening?

6. Interpreting Scientific Illustrations Diagramthe composition of muscle fibers as shown in theInside Story. For more help, refer to ThinkingCritically in the Skill Handbook.


Rate

of o

xyge

nco

nsum

ptio

n

Work rate

Oxygen Consumption During Exercise

Bloo

d la

ctic

aci

d

Work rate

Shift towardanaerobicprocesses

Blood Lactic Acid Levels During Exercise

Figure 34.12Athletic trainers use information about muscle functioning duringexercise to establish appropriate levels of intensity for training.

As an individual increases the intensity of his or her workout,the need for oxygen goes up in predictable increments.

AA

An upswing in the presence of lactic acid in the bloodstreamcan be used to indicate the point at which anaerobic respira-tion becomes the dominant means of ATP production.

BB

3 AssessCheck for UnderstandingAsk students to diagram andexplain the sliding filament the-ory of muscle contraction.

ReteachReview the three types of musclesand where in the body each isfound.

ExtensionHave interested students researchdiseases and disorders that affectthe muscular system. Have themprepare a report on one of thedisorders for their portfolios.

Performance Provide stu-dents with a diagram of musclesof the human body. Have studentsmake a key to identify each typeof muscle.

4 CloseDiscussionDiscuss the function of each typeof muscle. Help students recog-nize the relationship between theskeleton and skeletal muscles. L1

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TendonSkeletal muscle

Myofibril

Filaments Actin

Myosin

Sarcomere

Bundles ofmuscle fibers


A Muscle

Locomotion is made possible by the contraction andrelaxation of muscles. The sliding filament theory of

how muscles contract can be better understood by exam-ining the detailed structure of a skeletal muscle.

Critical Thinking How does a nerve signal cause askeletal muscle to contract?

Magnification: 1500�

Skeletal muscle is responsible for moving your bones.

INSIDESSTORTORYY

INSIDE

Muscle structure When youtease apart a typical skeletalmuscle and view it under amicroscope, you can see that it consists of bundles of fibers.A single fiber is made up ofmyofibrils which, in turn, aremade up of actin or myosin filaments. Each myofibril can be broken up into func-tional units called sarcomeres.

11

Nerve signal When askeletal muscle receives asignal from a nerve, cal-cium is released insidethe muscle fibers, causing them to contract.

22

Contraction The presenceof calcium causes attachmentsto form between the thickmyosin and thin actin fila-ments. The actin filaments are then pulled inwardtoward the center of eachsarcomere, shortening thesarco-mere and producing a muscle contraction. Whenthe muscle relaxes, the fila-ments slide back into theiroriginal positions.

33

Relaxed sarcomere

Section of a striated muscle fiber

Contracted sarcomere

Actin

Myosin

938

IINSIDENSIDESSTORTORYY

INSIDE

PurposeStudents gain further under-standing of the way muscle cellscontract.

Teaching Strategies■ Have students describe thestructure of skeletal muscle.■ Ask students to describe thedifferences between actin andmyosin filaments.

Visual Learning■ Ask students what makes up a

single muscle fiber. manymyofibril units Elicit whatchemical stimulates the forma-tion of attachments betweenmyosin and actin filaments.calcium

Critical ThinkingThe nerve signal causes calciumto be released in the muscle. Thecalcium causes actin and myosinfilaments to bind together. Theactin filaments are then pulledinward, resulting in a musclecontraction.

Knowledge Have studentswrite a short summary of why lac-tic acid builds up in muscle cellsduring intense exercise.


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Tying to Previous KnowledgePoint out that myofibrils of themuscles are a special type ofmicrofilament, as discussed previ-ously. This is a good time toreview ATP, along with aerobicand anaerobic metabolism.


Physically Challenged Locate a physically challenged spokesper-son who has a musculoskeletal disease andwho is willing to speak to the class aboutthe disorder. The focus of the discussionshould be on the nature of the disease,restrictions the disease places on the per-son, and treatments for the disease.

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P R O J E C TModeling Body Movement

Visual-Spatial Have students work-ing in groups construct models to

show how bones and muscles worktogether to move appendages. Moreadvanced students may wish to worktogether to prepare a model that demon-strates the sliding filament theory.

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The BioLab at theend of the chaptercan be used at thispoint in the lesson.

YOUR OWNDESIGN

YOUR OWNDESIGN

Section AssessmentSection AssessmentSection Assessment1. Smooth muscle cells are spindle shaped

and form the linings of organs. Theyapply pressure and squeeze. Cardiacmuscle cells are striated and form acontraction network in the heart.Skeletal muscle cells are striated. Theymove the body.

2. Calcium is released into the musclefiber, actin and myosin filaments form

attachments, and the actin filamentsare pulled inward toward the center ofeach sarcomere.

3. Exercise stresses muscles and causesfibers to increase in size and strength.Exercise cannot change muscle function.

4. Muscle strength depends on the thick-ness of the muscle fibers and how manyof the fibers contract at one time.

5. Internal organs utilize smooth muscleto perform their functions, such asbreathing and digestion.

6. The drawing should reflect that musclefibers are made of tiny cylinders calledmyofibrils. Each myofibril is made ofmyosin and actin filaments arranged ina pattern within the sarcomere.

939


Reinforcement and StudyGuide, p. 154

Content Mastery, pp. 169,171-172

Reteaching Skills Transparency 49 andMaster

Laboratory Manual, pp. 251-254 L2

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would work after 30 minutes ofrest? Explain your answer.

PLAN THE EXPERIMENTPLAN THE EXPERIMENT

1. Design a repetitive exercise for a particular group of muscles. Make sure you cancount single repetitions of the exercise (for example, one sit-up or one jumping jack) over time.

2. Work in pairs, with one member of the team being a timekeeper and the othermember performing the exercise.

3. Consider setting up yourexperiment so that the amountof resistance is the independentvariable. Compare your design with those of othergroups.

Check the Plan1. Be sure that the exercises are

ones that can be done rapidlyand cause a minimum of dis-ruption to other groups in theclassroom.

2. Consider how long you will dothe activity and how often youwill record measurements.

3. Make sure your teacher hasapproved your experimentalplan before you proceed further.

4. Make a table in which you canrecord the number of exerciserepetitions per time interval.

5. Carry out the experiment.6. On a piece of graph paper,

plot the number of repetitionson the vertical axis and thetime intervals on the horizon-tal axis.


1. Making Inferences What effect did repeating the exerciseover time have on the musclegroup?

2. Comparing and ContrastingAs you repeated the exercise over time, how did your musclesfeel?

3. Recognizing Cause and EffectWhat physiological factors areresponsible for fatigue?

4. Thinking Critically How well doyou think your fatigued muscles

ANALYZE AND CONCLUDEANALYZE AND CONCLUDE

Going FurtherGoing Further

Project Design an experiment that willenable you to measure the strength of muscle contractions.

To find out more aboutmuscles, visit the Glencoe

Science Web Site. www.glencoe.com/sec/science

First minute

Second minute

Third minute

Fourth minute

Fifth minute

Number of repetitionsTime interval

Sample Data Table

YOUR OWNDESIGN

YOUR OWNDESIGN

1. The muscle groups becamefatigued and the number ofrepetitions of the activitywent down as more trialswere run.

2. The muscles felt tired andmay even have begun to hurttoward the end. It becameharder to do the activity andthe strength of each contrac-tion was reduced.

3. Cells are running out of oxy-gen and accumulating toxicproducts such as lactic acidand carbon dioxide as themuscles change to anaerobicprocesses.

4. Fatigued muscles shouldwork as well after a rest of 30minutes as they did beforefatigue became a factor. Theaccumulated lactic acid hasbeen broken down as theoxygen supply in the musclecells has been replenishedduring the rest.

Error AnalysisStudents must put real effort intotheir activity in order to see theresults of fatigue.

Portfolio Have studentsplace their laboratory reports,including their tables and graphs,in their journals. Use thePerformance Task AssessmentList for Science Journal in PASC,p. 103. L2

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ANALYZE AND CONCLUDEANALYZE AND CONCLUDE

941

Data and ObservationsStudent graphs should show that the num-ber of exercise repetitions goes down overtime as the muscles become tired.

Going FurtherGoing Further

Ask students how athletes suchas marathon runners continueto exercise at a high level for 3or more hours. Why don’t theirmuscles fatigue after a fewminutes?

ObjectivesIn this BioLab, you will:■ Hypothesize whether or not muscle

fatigue affects the amount of exer-cise muscles can accomplish.

■ Measure the amount of exercisedone by a group of muscles.

■ Make a graph to show the amount ofexercise done by a group of muscles.

Possible Materialsstopwatch or clock with second handgraph papersmall weightswooden box or step stool

Skill HandbookUse the Skill Handbook

if you need additional help with this lab.


Does fatigue affect the abilityto perform an exercise?

T he movement of body parts results from the contraction and relax-ation of muscles. In this process, muscles use energy from aerobic

and anaerobic respiration. When exercise is continued for a long period oftime, the waste products of fermentation accumulate and muscle fibersare stressed, causing fatigue. Fatigue affects the various muscles differ-ently. It also affects individuals differently, even when they are perform-ing the same tasks. Muscular strength, muscular endurance, and theamount of effort required to perform a task are all variables to consider.

YOUR OWNDESIGN

YOUR OWNDESIGN

ProblemHow does fatigue affect the num-

ber of repetitions of an exercise youcan accomplish? How do differentamounts of resistance affect rate offatigue?

HypothesesHypothesize whether or not muscle

fatigue has any effect on the amountof exercise muscles can accomplish.Consider whether fatigue occurswithin minutes or hours.

PREPARATIONPREPARATION

YOUR OWNDESIGN

YOUR OWNDESIGN

940

Time AllotmentOne class period

Process Skillsobserve and infer, communicate,measure in SI, predict, form ahypothesis, design an experiment

Alternative MaterialsStopwatches are not necessary ifa clock with a second hand is visi-ble to all students.

Possible HypothesesIf a muscle becomes fatigued,then the muscle will not be ableto do as much work.

If a muscle becomes fatigued,its capacity to do work will not bediminished.

PREPARATIONPREPARATION

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PLAN THE EXPERIMENTPLAN THE EXPERIMENT

Teaching Strategies■ One student should act as timekeeper.The exerciser should count the number oftimes he or she can carry out the exercise ina given time period, such as 3 minutes.■ Trials should be performed as closelytogether as possible, so that little musclerest occurs between trials. ■ Place a sample graph on the chalkboard

to help students prepare their graphs.

Possible Procedures■ Students should choose an exercise such

as how many times they can lift a weightin 3 minutes. They should repeat theexperiment 4 or 5 times so that the mus-cles become fatigued.


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Chapter 34 AssessmentChapter 34 Assessment

SUMMARYSUMMARY

Section 34.1

Section 34.2

Section 34.3

Main Ideas■ Skin regulates body temperature, protects the

body, and functions as a sense organ.■ Skin cells are constantly being shed and

replaced.■ Skin responds to injury by producing new cells

and signaling a response to fight infection.

Vocabularydermis (p.925)epidermis (p.923)hair follicle (p.926)keratin (p.923)melanin (p.925)

Skin: TheBody’sProtection

Vocabularyappendicular skeleton

(p.929)axial skeleton (p.929)bursa (p.930)compact bone (p.932)joint (p.929)ligament (p.930)osteoblast (p.932)osteocyte (p.932)red marrow (p.933)spongy bone (p.932)tendon (p.930)yellow marrow (p.933)

Vocabularyactin (p.937)cardiac muscle (p.936)involuntary muscle

(p.936)myofibril (p.937)myosin (p.937)sarcomere (p.937)skeletal muscle (p.936)sliding filament theory

(p.937)smooth muscle (p.935)voluntary muscle (p.936)

CHAPTER 34 ASSESSMENT 943

1. All of the following are tissues found in theskin except:a. connective c. muscleb. epithelial d. cardiac

UNDERSTANDING MAIN IDEASUNDERSTANDING MAIN IDEAS 2. Which of the following is NOT a function ofthe skeletal system?a. provide a framework for body tissuesb. regulate temperaturec. produce blood cellsd. act as a storehouse for minerals

Main Ideas■ The skeleton is made up of the axial and appen-

dicular skeletons. ■ The skeleton supports the body, provides a

place for muscle attachment, protects vitalorgans, manufactures blood cells, and serves as astorehouse for calcium and phosphorus.

■ Joints allow movement between two or morebones where they meet.

Main Ideas■ There are three types of tissue: smooth, cardiac,

and skeletal.■ Muscles contract as filaments within the

myofibrils slide toward one another.■ Muscle strength depends on muscle fiber thick-

ness and the number of fibers contracting.

Muscles forLocomotion

Bones: TheBody’s Support

943

Main IdeasSummary statements can be usedby students to review the majorconcepts of the chapter.

Using the VocabularyTo reinforce chapter vocabulary, usethe Content Mastery Booklet andthe activities in the Interactive Tutorfor Biology: The Dynamics of Life onthe Glencoe Science Web Site.www.glencoe.com/sec/science


All ChapterAssessment

questions and answers have beenvalidated for accuracy and suitabil-ity by The Princeton Review.

X rays are a form of radiation emitted by X-raytubes and by some astronomical objects such as stars. Machines that use X rays to view

concealed objects are so common that you haveprobably had contact with one recently.

Dentists use them to examine teeth, doctors to inspect bones and organs, and airports to

look inside your carry-on baggage.

Wilhelm Röntgen, a German physics pro-fessor, accidentally discovered the X ray

in 1895. As he was studying cathode rays in ahigh-voltage vacuum tube, he noticed that ascreen lying nearby was giving off fluorescentlight. He eventually determined that special rays given off by the tube were able to penetratethe black box that enclosed it and strike thescreen, causing it to glow. Because he did notknow what these rays were, he called them Xrays, “X” standing for “unknown.” He made afilm of his wife’s hand (shown here), exposing the bones—the first permanent X ray of ahuman. Two months later, he published a shortpaper. Within a month of its publication, doc-tors in Europe and the U.S. were using X rays in their work.

Noninvasive diagnosis In medicine, X raysare passed through the body to photographicfilm. Bones and other dense objects show up aswhite areas on the film. As a result, the positionand nature of a break is clearly visible. The con-tours of organs such as the stomach can be seenwhen a patient ingests a high-contrast liquid;other organs can be marked with special dyes.

X rays generate a two-dimensional photo-graph with no depth. On the other hand, com-puterized scan system, such as a CAT scanner,can make a 3-D image by scanning an area manytimes at different angles. These 3-D images areuseful for viewing tissues shadowed by overlyingorgans.

Radiation treatments As X rays bombardatoms of tissues, electrons are knocked fromtheir orbits, resulting in damage to the exposedtissue cells. To protect healthy tissues, absorptivemetals are used as shields. You’ve probably had adental X ray where the dental assistant spread aheavy lead apron across your chest. The destruc-tive nature of X rays has proven useful in thetreatment of cancers, where cancerous cells aretargeted and destroyed.


ConnectionPhysicsPhysics

Connection X rays—The Painless Probe

Why would an X ray be useful in diagnosing afractured bone but not a sprained ligament?

To find out more about X rays,visit the Glencoe Science Web

Site.www.glencoe.com/sec/science

CONNECTION TO BIOLOGYCONNECTION TO BIOLOGY

A CAT scan of the humanbrain (above), and an X ray of Bertha Röntgen’shand (right).

942

PurposeStudents will learn about someuses of X rays in medicine.

Teaching Strategies■ Ask students to share experi-ences about when they have hadX rays taken. Ask students toexplain why the X rays wereneeded.■ Hang up X rays on the win-dows or show them on the over-head as you discuss the PhysicsConnection. Point out how softtissues do not show up on the Xrays.

Connection to BiologyAn X ray will show the image of abroken bone because X rays don’tpass through dense bone. X rayswill not, however, show if a liga-ment is sprained because the Xrays pass through soft tissue andthus do not create an image.

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Connection

1. d2. b

UNDERSTANDING MAIN IDEASUNDERSTANDING MAIN IDEAS

VIDEODISCThe Secret of LifeX Ray

!7SÇjI"

!7T_tD"CAT Scan

Internet Address Book

Note Internet addressesthat you find useful in

the space below for quick reference.

VIDEODISCThe Infinite Voyage: Unseen Worlds

Technology ReconstructsEgyptian Mummies (Ch. 1)

6 min. 30 sec.

Digital X Rays, 3-D X Rays:Detection Made Easy (Ch. 8)

7 min.

!7-8J"

!7s~D"

VIDEOTAPEMindJogger Videoquizzes

Chapter 34: Protection, Support, and Loco-motionHave students work in groups as they playthe videoquiz game to review key chapterconcepts.


Chapter Assessment, pp. 199-204MindJogger VideoquizzesComputer Test BankBDOL Interactive CD-ROM, Chapter 34

quiz




CHAPTER 34 ASSESSMENT 945

23. How could you use a person’s skeleton todetermine his or her age?

24. Outline how the skin helps the body main-tain body temperature.

25. Interpreting Data The graph below showsthe time relationship between muscle forceand calcium levels inside a contracting mus-cle fiber. Describe the cause-and-effect rela-tionship shown between the development ofmuscle force and calcium levels in the fiber.

26. Concept Mapping Complete the conceptmap by using the following vocabulary terms:actin, myofibrils, skeletal muscles, myosin.

THINKING CRITICALLYTHINKING CRITICALLY

ASSESSING KNOWLEDGE & SKILLSASSESSING KNOWLEDGE & SKILLS

Bone is living tissue that includes differentkinds of cells and structures.

Interpreting Scientific IllustrationsUse the diagram above to answer the following questions.1. Place the structures of the human body

shown in the diagram in order fromleast to most complex.a. 1, 2, 3, 4 c. 4, 3, 2, 1 b. 1, 3, 2, 4 d. 4, 2, 3, 1

2. Which diagram represents one osteonsystem?a. 1 c. 3b. 2 d. 4

3. Which of the following demonstratesthat bones are alive?a. Bones grow in both length and diam-

eter.b. Bones are able to repair themselves.c. Bones contain living cells called

osteocytes.d. All of the above.

4. Interpreting Data The center of mostlong bones is hollow. What advantagemight having bones with hollow centersconfer to humans and other mammals?

contain bundles of fibers made up of

1.

which are made of thin filaments

of the protein

2.

3. 4.

which are made of thick filaments

of the protein

For additional review, use the assessmentoptions for this chapter found on the Biology: TheDynamics of Life Interactive CD-ROM and on theGlencoe Science Web Site.www.glencoe.com/sec/science

CD-ROM

Mus

cle

forc

e an

dca

lciu

m le

vels

Time (milliseconds)

20 40 60 80 100 120 140 160 180 200

Calcium level

Muscle force

Calcium levels in Contracting Muscle

11 22 33

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23. Degree of bone fusion can beused to identify the age of askeleton. The more fusion, theolder the skeleton. The amountof cartilage present and brittle-ness of bone also may be usedto determine age.

24. Sweat evaporates from thebody, cooling it in the process.Blood vessels in the skin canalso constrict to conserve heator dilate to increase heat loss.

25. A large increase in muscle cellcalcium precedes (and initiates)muscle contraction.

26. 1. Skeletal muscles; 2. Myofibrils;3. Myosin; 4. Actin

THINKING CRITICALLYTHINKING CRITICALLY


1. b2. c3. d4. Hollow bones allow

humans and other mam-mals to have strengthwith reduced weight.


3. Which of the following is a skin pigment thatprotects cells from solar radiation damage?a. keratin c. melaninb. epidermis d. dermis

4. Which of the following is NOT found in thedermis?a. blood vessels c. keratinb. nerves d. oil glands

5. Which of the following are nourished by blood vessels in the central canal of this structure?a. dermisb. bone cellsc. epidermisd. sarcomeres

6. When exposed to sunlight, skin is able toproduce which vitamin?a. Vitamin C c. Vitamin Bb. Vitamin A d. Vitamin D

7. Which type of joint allows rotational move-ment?

a. c.

b. d.

8. All of the following are types of muscleexcept:a. epidermal c. smoothb. cardiac d. skeletal

9. As a muscle relaxes after contraction, actinfilaments:a. slide in toward each otherb. slide away from each otherc. are digested into their component proteinsd. lengthen and become invisible under the

microscope10. Skin plays a role in:

a. storing calciumb. regulating body temperaturec. manufacturing blood cellsd. supporting the body

11. Ridges in the ________ of your skin give youa unique fingerprint.

12. ________ grow to become mature bone cells.13. ________ burns are the most severe, resulting

in destroyed epidermis and ________.14. The fetal appendicular skeleton is mostly

made of ________.15. The ________ skeleton includes the skull,

ribs, vertebral column, and sternum.16. ________ fills the cavities of bones and is

responsible for the production of red andwhite blood cells.

17. Epidermal cells in the skin are derived fromthe ________ layer of the embryo.

18. In movable joints, a fluid-filled sac called a________ prevents bones from rubbingagainst each other.

19. Muscles are attached to bones by ________.20. Skeletal muscle is under ________ control,

while cardiac muscle is under ________control.

21. Why do sprains usually occur in the ankles,wrists, and knees?

22. How would the destruction of red marrowaffect other systems of the body?

APPLYING MAIN IDEASAPPLYING MAIN IDEAS

944 CHAPTER 34 ASSESSMENT

TEST–TAKING TIPTEST–TAKING TIP

Warm Up Before the Race On the day of your exam, arrive at the site earlyenough to relax, get settled, and go over yournotes. It will give you time to relax and prepareyour mind for the test.

944

3. c4. c5. b6. d7. a8. a9. b

10. b11. epidermis12. Osteoblasts13. Third-degree, dermis14. cartilage15. axial16. Red marrow17. ectodermal18. bursa19. tendons20. voluntary, involuntary

21. Ankles, wrists and knees arehighly movable joints that areespecially vulnerable to exces-sive twisting. The ankles andknees are also weight-bearingjoints, which makes them evenmore vulnerable.

22. If red bone marrow weredestroyed, the production ofred blood cells, white bloodcells, and blood-clotting cellfragments would be impaired.

APPLYING MAIN IDEASAPPLYING MAIN IDEAS



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Unit 10 The Human Body The Human Advance Planning