Skeletal System

Page 2:

• The skeleton has 206 bones

• Two basic types of bone tissue

  • Compact bone

    • Homogeneous

  • Spongy bone

    • Small needle-like pieces of bone

    • Many open spaces

Page 3:

• Compact versus Spongy Bone

  • Cortical (hard) bone

  • Trabecular (spongy) bone

  • Periosteum (membrane covering bone)

  • Articular cartilage

  • Blood vessels

  • Marrow

  • Epiphyseal plate

  • Medullary cavity

Page 4:

• Compact versus Spongy Bone

  • Compact Bone & Spongy (Cancellous Bone)

  • Lacunae containing osteocytes

  • Osteon of compact bone

  • Lamellae

  • Trabeculae of spongy bone

  • Caneliculi

  • Haversian canal

  • Periosteum

  • Volkmann's canal

Page 5:

• Parts of the skeletal system

  • Bones (skeleton)

  • Joints

  • Cartilages

  • Ligaments (bone to bone)(tendon=bone to muscle)

• Divided into two divisions

  • Axial skeleton

  • Appendicular skeleton – limbs and girdle

Page 7:

• Functions of Bones

  • Support of the body

  • Protection of soft organs

  • Movement due to attached skeletal muscles

  • Storage of minerals and fats

  • Blood cell formation

Page 8:

• Classification of Bones

  • Long bones

    • Typically longer than wide

    • Have a shaft with heads at both ends

    • Contain mostly compact bone

    • Examples: Femur, humerus

Page 9:

• Bone Formation (Ossification)

  • Intramembranous Ossification

    • Bones originate within sheetlike layers of connective tissues

    • Broad, flat bones (skull bones except mandible)

  • Endochondral Ossification

    • Bones begin as hyaline cartilage

    • Form models for future bones

    • Most bones of the skeleton

Page 10:

• Bone Formation (Endochondral)

  • Spongy Secondary Articular bone ossification cartilage

  • Deteriorating formation center

  • Spongy Epiphyseal cartilage bone blood

  • Hyaline matrix vessel cartilage

  • Primary Epiphyseal ossification Medullary plate center cavity cartilage

  • Bone Blood collar vessel of periosteal bud

  • Mesenchymal cells

  • The cartilage differentiate model of the

  • Capillaries chondrocytes future bony penetrate skeleton and cartilage.

  • Cartilage and the chondrocytes

  • Ossification of the Perichondrium perichondrium transforms into continue to grow epiphses; cartilage form at ends of the remains at periosteum.

  • Periosteal collar bone.

  • Secondary epiphyseal (growth) ossification center develops.

  • Primary ossification cartilage center develops

Page 11:

• Bone Formation- - Stages of Intramembranous Ossification

  • Mesenchyme condensing to form the periosteum

  • Trabecula of woven bone

  • Blood vessel

  • Woven bone and periosteum form

  • Accumulating osteoid laid down between embryonic blood vessels

  • Result is a network of trabecular

  • Vascularized mesenchyme condenses on the external surface of the woven bone and becomes the periosteum

Page 12:

• Classification of Bones

  • Short bones

    • Generally cube-shape

    • Contain mostly spongy bone

    • Examples: Carpals, tarsals

Page 14:

• Classification of Bones

  • Flat bones

    • Thin and flattened

    • Usually curved

    • Thin layers of compact bone around a layer of spongy bone

    • Examples: Skull, ribs, sternum

Page 15:

• Classification of Bones

  • Irregular bones

    • Irregular shape

    • Do not fit into other bone classification categories

    • Example: Vertebrae and hip

Page 17:

• Bone Growth

  • 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

Page 18:

• Bone Growth

  • Bones are remodeled and lengthened until growth stops

  • Bones change shape somewhat

  • Bones grow in width

Page 20:

• 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

Page 21:

• Common Types of Fractures

  • Comminuted

    • Bone breaks into many fragments

    • Particularly common in the aged, whose bones are more brittle

  • Compression

    • Bone is crushed

    • Common in porous bones (i.e., osteoporotic bones)

  • Depressed

    • Broken bone portion is pressed inward

    • Typical of skull fracture

  • Impacted

    • Broken bone ends are forced into each other

    • Commonly occurs when one attempts to break a fall with outstretched arms

  • Spiral

    • Ragged break occurs when excessive twisting forces are applied to a bone

    • Common sports fracture

  • Greenstick

    • Bone breaks incompletely, much in the way a green twig breaks

    • Common in children, whose bones are more flexible than those of adults

Page 22:

• 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