1. Chapter 5 Bone formation. Growth and remodeling
Essentials of Human Anatomy & Physiology
Seventh Edition
Elaine N. Marieb
Chapter 5 Bone formation. Growth and remodeling
The word skeleton comes from the Greek word meaning “dried-up body.”
Our internal framework is designed and engineered to be strong and light.
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2. Changes in the Human Skeleton
In embryos, the skeleton is primarily hyaline cartilage
During development, much of this cartilage is replaced by bone
Cartilage remains in isolated areas
Bridge of the nose
Parts of ribs
Joints
HIGHLIGHT first bullet.
Slide 5.12
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3. Fetal Bone

4. Bone Growth (Ossification)
Epiphyseal plates allow for growth of long bone during childhood
New cartilage is continuously formed
Older cartilage becomes ossified (Ossification)
Cartilage is broken down
Bone replaces cartilage
Remember that lengthwise bone growth is controlled by growth hormones.
Slide 5.13a
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5. Bone Growth Bones are remodeled and lengthened until growth stops
Bones change shape somewhat
Bones grow in width (appositional growth)
The process at which bones grow in width is called appositional growth.
Slide 5.13b
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6. Long Bone Formation and Growth
Figure 5.4a
Slide 5.14a
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7. Long Bone Formation and Growth
Figure 5.4b
Slide 5.14b
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8. Types of Bone Cells Osteocytes Osteoblasts Osteoclasts
Mature bone cells
Osteoblasts
Bone-forming cells
Osteoclasts
Bone-destroying cells
Break down bone matrix for remodeling and release of calcium
Bone remodeling is a process by both osteoblasts and osteoclasts
Know these three cells.
Control of these bone remodeling cells (osteoblasts and osteoclasts) is controlled by hormones from the parathyroid glands called Parathyroid Hormone (PTH).
Osteoblasts become trapped in the layers of new matrix and become osteocytes.
Slide 5.15
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9. Rickets A disease of children in which the bones fail to calcify.
Rickets is usually due to a lack of calcium in the diet or lack of vitamin D, which is needed to absorb calcium into the blood.

10. Bone Fractures A break in a bone Types of bone fractures
Closed (simple) fracture – break that does not penetrate the skin
Open (compound) fracture – broken bone penetrates through the skin
Bone fractures are treated by reduction and immobilization
Realignment of the bone
HIGHLIGHT “Open (compound) fracture – Broken bone penetrates through the skin.”
Slide 5.16
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11. Common Types of Fractures
Be familiar with comminuted, compression, and greenstick fractures.
Table 5.2
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13. Repair of Bone Fractures
Hematoma (blood-filled swelling) is formed
Break is splinted by fibrocartilage to form a callus
Fibrocartilage callus is replaced by a bony callus
Bony callus is remodeled to form a permanent patch
Slide 5.18
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14. Stages in the Healing of a Bone Fracture
You need to know all four stages in the healing of a bone fracture.
Figure 5.5
Slide 5.19
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