1. The Skeletal System – Part I
Learning Outcome C1

2. Student Achievement Indicators
At the end of this learning outcome students should be able to:
Describe the general structure of bone and the functions of its parts
Explain the process of bone growth and repair
Explain the causes, effects, symptoms and treatments of osteoporosis

3. Skeletal System Consists of bones, joints, cartilage and ligaments
Bone tissue is living, but contains non-living minerals such as calcium and phosphorus
Appears dead and dried up
Contains 206 bones

6. Function Support weight Protect and support soft body organs
With assistance from the muscles, allows the body to move
Stores minerals such as calcium and phosphorus
Bone marrow produces red blood cells

7. Size and Shape Reflect function
Bones are classified in the following ways:
Long bones – longer than wide (arms and legs)
Short bones – shaped like cubes (ankles and wrists)
Flat bones – thin, flat and curved (breastbone and skull)
Irregular bones – unique shape (hip bone, vertebrae)

10. Bone Formation Known as osseous tissue
Bone cells are called octeocytes
Osteocytes secrete a matrix that contains calcium and other minerals.
Bones contain protein that made bones elastic
Minerals make bones hard
Bone is the hardest type of connective tissue

12. Compact & Spongy Bone There are two type of osseous tissue:
Compact bone – hard, dense, found in the shafts of long bones and on the outer surface of other bones.
Made up of microscopic units called haversian systems
Spongy bone – less dense, and located at the ends of long bones and in the centers of other bones.

13. Compact & Spongy Bone
Spaces in the spongy bone are important for two reason:
Decrease the weight of the bone
Contain red bone marrow, which supplies the bone with blood and produces red blood cells.

14. Parts of a Long Bone Diaphysis Shaft of bone Made up of compact bone
Designed for strength

15. Parts of a Long Bone Epiphyisis Epiphyseal Disc
Enlarged ends of long bones
Articulates with another bone at a joint
Epiphyseal Disc
Band of hyaline cartilage located a the ends of long bones between the epiphysis and diaphyisis
Location of longitudinal growth

16. Parts of a Long Bone Medullary Cavity Periosteum
Hollow center of diaphysis
In infancy filled with bone marrow to form red blood cells
Adults filled with yellow marrow, which functions in fat storage
Periosteum
Fibrous connective tissue that covers the diaphysis
Provides point of attachment for muscle, and contain blood vessels for underlying bone.

17. Parts of a Long Bone Articular cartilage
Outer surface of epiphysis and forms a smooth shiny surface that reduces friction at joints

18. Ossification Formation of bone
Fetus – converts cartilage and connective tissue to bone
Ossification begins with osteoblasts
Osteoblasts secrete calcium and other minerals into spaces between connective tissue.
Occurs when cartilage is replaced with bone
Occurs in long bones until all cartilage is replaced by but articular cartilage.

19. Growing Taller Occurs at epiphyseal plants
Growth continues as long as cartilage is formed at the epiphyseal plate.
Growth stops when epiphyseal play become ossified
Epiphyseal plat is sensitive to growth and sex hormones
Growth hormones stimulate growth
Sex hormones cause plate to fuse and growth to stop.
Epiphyseal plate is very sensitive to estrogen, reason why girls are generally shorter
An injured epiphyseal plate can stop growth
Example – one leg longer than the other.

20. Growing Thicker and Wider
Bones continue to grow in with even after they stop growing in length.
Bones are constantly reshaped by osteoblast (bone-forming cells) and osteoclasts (bone-destroying cells).
Osteoclasts break down old bone
Osteoblasts lay down new bone
Exercise helps promote bone growth because it keeps calcium in the bones.

21. Break vs. Fracture
A compound fracture is a broken bone that pierced the skin.
The ends of the bone usually cause extensive tissue damage
Greater chance of infection

22. Greenstick Fracture An incomplete break in the bone
Usually occurs in children
Named after the bending of a young tree