http://evolve.elsevier.com/Herlihy

chapte r

8 Skeletal System

KEY TERMS

abduction (p. 136)

adduction (p. 136)

appendicular skeleton (p. 116)

articulation (p. 114)

axial skeleton (p. 116)

diaphysis (p. 114)

epiphysis (p. 114)

extension (p. 136)

flexion (p. 136)

fontanel (p. 120)

haversian system (p. 113)

osteoblast (p. 113)

osteoclast (p. 115)

periosteum (p. 114)

synovial joint (p. 132)

OBJECTIVES

1. List the functions of the skeletal system.

2. Describe the structure of a long bone.

3. Differentiate between the composition and location of

compact and spongy bone.

4. Describe how bones grow in length and width.

5. Describe the roles of osteoblasts and osteoclasts.

6. List the bones of the axial skeleton.

7. List the bones of the appendicular skeleton.

8. Label important landmarks for selected bones on the

skeleton.

9. List the main types and functions of joints.

10. Describe the types of joint movement.

The skeletal system consists of the bones, joints, andcartilage and ligaments associated with the joints. Bonetissue is living and metabolically active, but because itcontains so much nonliving material, such as calciumand phosphorus, it appears dead or dried up. In fact,the word skeleton comes from a Greek word meaningdried up body.

The skeletal system, however, is anything but dead.It contains 206 bones that are very much alive and per-form a number of important functions.

Do You Know...

About growing down with osteoporosis?

Osteoporosis is a commonbonedisorder, especially in postmen-

opausal women. Osteoporosis is characterized by a decline in

bone-making activity and the lossof bone tissue.As tissue is lost,

the bones weaken and break. Common sites of fracture caused

by osteoporosis are the hip, wrist, and vertebrae. Osteoporosis

may also affect the vertebral column. As the vertebrae collapse,

nerves may be pinched, causing severe pain. The collapsed

vertebrae also cause a shortening of the vertebral column (grow-

ing down) and a change in its curvature. This change in shape, in

turn, often impairs the functioning of organs such as the lungs.

ARRANGEMENT AND FUNCTIONSOF BONES

As you can see from Figure 8-1, the bones of the skele-tal system are arranged to provide a framework for ourbodies. The skeletal system gives us our basic shape.Imagine what you would look like without bones!

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