Ross & Wilson Anatomy and Physiology in Health and Illness (177 page)

16.1
Bone formation and growth
382

16.2
Fracture and repair
384

16.3
Vertebral column and spinal nerves
391

16.4
Types of joint movement
402

16.5
Contraction and relaxation of sarcomeres
411

16.6
Neuromuscular junction
411

16.7
Types of skeletal muscle contraction
412

The musculoskeletal system consists of the bones of the skeleton, their joints and the skeletal (voluntary) muscles that move the body. The characteristics and properties of joints, and of bone and muscle tissue, are discussed in this chapter.

The illnesses section at the end of the chapter describes some disorders of bone, muscle and joints.

Bone

Learning outcomes

After studying this section you should be able to:

state the functions of bones

list five types of bones and give an example of each

outline the general structure of a long bone

describe the structure of compact and spongy bone tissue

describe the development of bone

explain the process of bone healing

identify the factors that delay bone healing

describe two complications of fractures

outline the factors that determine bone growth.

Although bones are often thought to be static or permanent, they are highly vascular living structures that are continuously being remodelled.

Functions of bones

The functions of bones include:

•
provision of the framework of the body

•
giving attachment to muscles and tendons

•
allowing movement of the body as a whole and of parts of the body, by forming joints that are moved by muscles

•
forming the boundaries of the cranial, thoracic and pelvic cavities, protecting the organs they contain

•
haemopoiesis, the production of blood cells in red bone marrow (
p. 58
)

•
mineral storage, especially calcium phosphate – the mineral reservoir within bone is essential for maintenance of blood calcium levels, which must be tightly controlled.

Types of bones

Bones are classified as long, short, irregular, flat and sesamoid.

Long bones

These consist of a shaft and two extremities. As the name suggests, these bones are longer than they are wide. Examples include the femur, tibia and fibula.

Short, irregular, flat and sesamoid bones

These have no shafts or extremities and are diverse in shape and size. Examples include:

•
short bones – carpals (wrist)

•
irregular bones – vertebrae and some skull bones

•
flat bones – sternum, ribs and most skull bones

•
sesamoid bones – patella (knee cap).