The Skeletal SystemPart II

Bone DevelopmentBone Development

Slide 5.12Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings

Osteogenesis (ossification) = the process of bone tissue formation

In embryos this leads to the formation of the bony skeleton

In children and young adults, ossification occurs as part of bone growth

In adults, it occurs as part of bone remodeling and bone repair

Changes in the Human SkeletonChanges in the Human Skeleton

Slide 5.12Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings

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

Bone GrowthBone Growth

Slide 5.13aCopyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings

Epiphyseal plates allow for growth of long bone during childhood

New cartilage is continuously formed

Older cartilage becomes ossified

Cartilage is broken down

Bone replaces cartilage

Bone GrowthBone Growth

Slide 5.13bCopyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings

Bones are remodeled and lengthened until growth stops

Bones change shape somewhat

Bones grow in width

Long Bone Formation and GrowthLong Bone Formation and Growth

Slide 5.14aCopyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings

Figure 5.4a

Long Bone Formation and GrowthLong Bone Formation and Growth

Slide 5.14bCopyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings

Figure 5.4b

Types of Bone CellsTypes of Bone Cells

Slide 5.15Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings

Osteocytes 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

Bone Remodeling and Modeling

http://youtu.be/0dV1Bwe2v6c

Bone FracturesBone Fractures

Slide 5.16Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings

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

Bone FracturesBone Fractures

Common Types of FracturesCommon Types of Fractures

Compression FracturesCompression Fractures

Depression FractureDepression Fracture

Compacted FractureCompacted Fracture

Spiral FractureSpiral Fracture

Greenstick FractureGreenstick Fracture

Repair of Bone FracturesRepair of Bone Fractures

Slide 5.18Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings

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

Stages in the Healing of a Bone Stages in the Healing of a Bone FractureFracture

Slide 5.19Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings

Figure 5.5

Anatomy of a Fracture

• https://www.youtube.com/watch?v=P5HwYWShBhw&list=UUDCWgYMRqAQL8uqghy328-g