CHAPTER INVESTIGATIONCHAPTER INVESTIGATION

604 Unit 5: Human Biology

A Closer Look at MusclesOVERVIEW AND PURPOSE You use the muscles in yourbody to do a variety of things. Walking, talking, reading thewords on this page, and scratching your head are all actions thatrequire muscles. How do your muscles interact with your bones? In this investigation you will

• • examine chicken wings to see how the muscles and thebones interact

• compare the movement of the chicken wing with themovement of your own bones and muscles

What are some characteristics of muscles?

Write a hypothesis to propose how muscles interact with bones.Your hypothesis should take the form of an ”If . . . , then . . . ,because . . .“ statement.

Make a data table like the one shown on the sample notebookpage. Put on your protective gloves. Be sure you are wearinggloves whenever you touch the chicken.

Obtain a chicken wing from your teacher. Rinse it in water andpat dry with a paper towel. Place it in the tray.

Extend the wing. In your notebook, drawa diagram of the extended wing. Be sureto include any visible external structures.Label the following on your diagram:lower limb, upper joint, and the wing tip.

Use scissors to removethe skin. Use caution so that you cut onlythrough the skin. Peelback the skin and anyfat so you can examinethe muscles.

Procedure

Hypothesize WriteIt Up

Problem WriteIt Up

MATERIALS• uncooked chicken wing

and leg (soaked inbleach)

• paper towels• dissection tray • scissors

step 3

step 4

Chapter 17: Systems, Support, and Movement 605

The muscles are the pink tissues that extend fromone end of the bone to the other. Locate these inthe upper wing and observe the way they movewhen you move the wing. Record your observa-tions in your notebook.

Repeat this procedure for the muscles in thelower wing. In your notebook, draw a diagramof the muscles in the chicken wing.

There are also tendons in the chicken wing.These are the shiny white tissues at the end of the muscles. Add the tendons to your diagram.

Dispose of the chicken wing and parts accordingto your teacher’s instructions. Be sure to washyour hands well.

1. RECORD Write a brief description of howthe bones and muscles work together toallow movement.

2. EVALUATE What difficulties, if any, did you encounter in carrying out this experiment?

1. INTERPRET How does the chicken wingmove when you bend it at the joint?

2. OBSERVE What happens when you pullon one of the wing muscles?

3. COMPARE Using your diagram of thechicken wing as an example, locate the same muscle groups in your own arm. Howdo they react when you bend your elbow?

4. APPLY What role do the tendons play inthe movement of the muscles or bones?

CHALLENGE Using scissors, carefully removethe muscles and the tendons from the bones.Next find the ligaments, which are locatedbetween the bones. Add these to your diagram.Describe how you think ligaments function.

INVESTIGATE Further

Conclude WriteIt Up

Observe and Analyze WriteIt Up

A Closer Look at Muscles

Problem What are some characteristics of muscles?

Table 1. Observations

Draw your diagrams

Extended wingMuscles in the up

per wing

Muscles in the lower wing

Muscles in the wing

Write your observations

606 Unit 5: Human Biology

Chapter Review

The human body is made up of systems thatwork together to perform necessary functions.

KEY CONCEPTS SUMMARY

VOCABULARYtissue p. 586organ p. 587organ system p. 588homeostasis p. 588

VOCABULARYskeletal system p. 590compact bone p. 591spongy bone p. 591axial skeleton p. 592appendicular skeletonp. 592

VOCABULARYmuscular system p. 599skeletal muscle p. 600voluntary muscle p. 600smooth muscle p. 600involuntary musclep. 600

cardiac muscle p. 600

The skeletal system provides support and protection.

Bones are living tissue. The skeleton is the body’s framework and has two main divisions,the axial skeleton and the appendicularskeleton. Bones come together at joints.

The muscular system makes movement possible.

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CONTENT REVIEWCLASSZONE.COM

The human body is complex.You can think of the body as having five levels of organization: cells, tissues,organs, organ systems, and the whole organism itself. The different systemsof the human body work together to maintain homeostasis.

Types of muscle Function

skeletal muscle, voluntary moves bones, maintains posture,maintains body temperature

smooth muscle, involuntary moves internal organs, such as the intestines

cardiac muscle, involuntary pumps blood throughout the body

Tissue (cardiac muscle)

Cells(cardiac

muscle cells)

Organ (heart) Organ system(circulatory system)

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2 3 4

Organism(human)

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Chapter 17: Systems, Support, and Movement 607

Reviewing Vocabulary

In one or two sentences describe how thevocabulary terms in each of the followingpairs of words are related. Underline eachvocabulary term in your answer.

1. cells, tissues

2. organs, organ systems

3. axial skeleton, appendicular skeleton

4. skeletal muscle, voluntary muscle

5. smooth muscle, involuntary muscle

6. compact bone, spongy bone

Reviewing Key Concepts

Multiple Choice Choose the letter of the bestanswer.

7. Which type of tissue carries electrical impulsesfrom your brain?

a. epithelial tissue

b. muscle tissue

c. nerve tissue

d connective tissue

8. Connective tissue functions to provide

a. support and strength

b. messaging system

c. movement

d. heart muscle

9. Bone cells lie within a network made of

a. tendons

b. calcium

c. marrow

d. joints

10. The marrow produces

a. spongy bone

b. red blood cells

c. compact bone

d. calcium

11. Which bones are part of the axial skeleton?

a. skull, shoulder blades, arm bones

b. skull, spinal column, leg bones

c. shoulder blades, spinal column, and hipbones

d. skull, spinal column, ribs

12. Bones of the skeletonconnect to each other at

a. tendons

b. ligaments

c. joints

d. muscles

13. How do muscles contribute to homeostasis?

a. They keep parts of the body together.

b. They control the amount of water in thebody.

c. They help you move.

d. They produce heat when they contract.

14. Cardiac muscle is found in the

a. heart

b. stomach

c. intestines

d. arms and legs

15. The stomach is made up of

a. cardiac muscle

b. skeletal muscle

c. smooth muscle

d. voluntary muscle

Short Answer Write a short answer to eachquestion.

16. What is the difference between spongy boneand compact bone?

17. The root word homeo means “same,” and the root word stasis means “to stay.” How dothese root words relate to the definition ofhomeostasis?

18. Hold the upper part of one arm between yourelbow and shoulder with your opposite hand.Feel the muscles there. What happens to thosemuscles as you bend your arm?T

608 Unit 5: Human Biology

24. COMPARE AND CONTRAST How is the skeletalsystem of your body like the framework of ahouse or building? How is it different?

25. SUMMARIZE Describe three important functionsof the skeleton.

26. APPLY The joints in the human body can bedescribed as producing three types of move-ment. Relate these three types of movement to the action of brushing your teeth.

27. COMPARE AND CONTRAST When you stand, themuscles in your legs help to keep you balanced.Some of the muscles on both sides of your legbones contract. How does this differ from howthe muscles behave when you start to walk?

28. INFER Muscles are tissues that are made up ofmany muscle fibers. A muscle fiber can eitherbe relaxed or contracted. Some movementsyou do require very little effort, like picking upa piece of paper. Others require a lot of effort,like picking up a book bag. How do you thinka muscle produces the effort needed for asmall task compared with a big task?

29. INFER Look again at the picture on pages582–583. Now that you have finished thechapter, how would you change or add details to your answer to the question on the photograph?

30. SUMMARIZE Write a paragraph explaining howskeletal muscles, bones, and joints worktogether to allow the body to move and beflexible. Underline the terms in your paragraph.

If you are doing a unit project, make a folder foryour project. Include in your folder a list ofresources you will need, the date on which theproject is due, and a schedule to track yourprogress. Begin gathering data.

Thinking Critically

19. PROVIDE EXAMPLES What are the levels oforganization of the human body from simpleto most complex? Give an example of each.

20. CLASSIFY There are four types of tissue in thehuman body: epithelial, nerve, muscle, andconnective. How would you classify blood?Explain your reasoning.

21. CONNECT A clam shell is made of a calciumcompound. The material is hard, providing protection to the soft body of a clam. It is alsolightweight. Describe three ways in which thehuman skeleton is similar to a seashell. What is one important way in which it is different?

Use the diagram below to answer the nexttwo questions

22. SYNTHESIZE Identify the types of joints thathold together the bones of the skull and ster-num. How do these types of joints relate tothe function of the skull and sternum?

23. SYNTHESIZE The human skeleton has two maindivisions. Which skeleton do the arms and legsbelong to? How do the joints that connect thearms to the shoulders and the legs to the hipsrelate to the function of this skeleton?

Chapter 17: Systems, Support, and Movement 609

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Interpreting DiagramsThe action of a muscle pulling on a bone can be compared to a simple machine calleda lever. A lever is a rod that moves about a fixed point called the fulcrum. Effort at oneend of the rod can move a load at the other end. In the human body, a muscle sup-plies the effort needed to move a bone—the lever. The joint is the fulcrum, and theload is the weight of the body part being moved. There are three types of levers,which are classified according to the position of the fulcrum, the effort, and the load.

Read the text and study the diagrams, and then choose the best answer for the questions that follow.

1. In a first-class lever

a. the load is at end of the lever opposite the fulcrum

b. the load is between the effort and the fulcrum

c. the fulcrum is between the load and the effort

d. the effort and load are on the same side

2. What is true of all levers?

a. The fulcrum must be located at the center of a lever.

b. The force of the load and effort point in thesame direction.

c. The load and effort are on the same side of thefulcrum.

d. The lever exerts a force in a direction opposite the weight of the load.

3. The lever represents what structure in the human body?

a. a joint c. a muscle

b. a bone d. a ligament

4. The main point of the diagram is to show

a. how bones work

b. that there are three types of joints and howthey are classified as levers

c. where to apply a force

d. the forces involved in moving parts of the body

Extended ResponseUse the diagrams above and terms from the wordbox to answer the next question. Underline eachterm you use in your answer.

5. Suppose you had a heavy box to lift. Your firstthought might be to bend over, stretch out yourarms, and grab the box. Your body would be act-ing as a simple machine. Identify the type of leverthis is and the parts of this machine.

6. A doctor would advise you not to lift a heavyobject, like a box, simply by bending over andpicking it up. That action puts too much strain onyour back. It is better to bend your knees, hold thebox close to your body, and then lift. How doesthis way of lifting change how you are using yourbody?

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E F L LF ELF EFirst-class lever Second-class lever Third-class lever

fulcrum load effort rodbone muscle joint