ALL ABOUT BONES

Matrix

• The matrix is made up of collagen fibers embedded in protein and polysaccharides

Weight of bone

1/3 organic

• Collagen (protein)

2/3 Inorganic salts

• Calcium (ca)

• Phosphorus (p)

• Magnesium (mg)

Function of bones

• Support

• Protection

• Leverage

• Storage

• Calcium (Blood cell formation)

• Hematopoiesis

Osteoblasts

• Cells that produce bone

• Harden matrix through ossification

• Once surrounded by bone osteoblasts are called osteocytes

Osteoclasts

• Remodel/Remove bone

Volkmann Canals

• Channels through bone matrix that contain blood vessels

• Blood vessels in the Volkmann canals join with blood vessels in the Haversian system

Nutrient foramina

• Channels in many large bones

• Contain large blood vessels, lymph vessels, and nerves

Cancellous bone

• Bone: Light and spongy

• Red bone marrow

Compact bone

• Dense and heavy

Cancellous bone

• Tiny spicules of bone that appear randomly arranged

• Spaces between the spicules contain bone marrow

Bone marrow

• Fills the spaces within bones

• 2 types: Red bone marrow, Yellow bone marrow

Red bone marrow

• Forms blood cells

• Majority of the bone marrow of young animals

• Only small portion in older animals

Yellow bone marrow

• Consists primarily of adipose connective tissue

• Most common in adult animals

• Can revert to red bone marrow if needed

Compact bone

• Shafts of long bones

• Outside layer of all bones

• Composed of Haversian systems that run lengthwise with the bone

Haversian system

• Concentric layers of ossified bone matrix arranged around a central canal

• Blood and lymph vessels and nerve

Long bones

• Femur

• Humerus

Short bone

• Carpal

• Tarsal bones

Flat bone

• Scapula

Irregular bone

• Sesamoid bones

• Vertebrae

Epiphyseal plates

• Cartilage located between diaphysis and epiphyses of bone

• Sites where new bone develops to allow long bones to lengthen

Epiphysis

• Articular cartilage

• Spongy bone

• Epiphyseal plate

Diaphysis

• Compact bone

• Periosteum

• Endosperm

• Medullary cavity

Periosteum

• Membrane that covers outer surfaces of bones

• Outer layer is composed of fibrous tissue

• Inner layer contains osteoblasts

• Not present on articular surfaces

Endosteum

• Membrane that lines the hollow interior surfaces of bones

• Also contains osteoblasts

Primary

• Growth center: Bones develop in the diaphyses

• Cartilage bone

• Cartilage is removed as bone is created

Secondary

• Growth centers: Develops in the epiphyses of the bone

Ossification

• When the bone has reached its full size the Epiphyseal plates completely ossify

Condyle

Large round articular surface

Head

• Spherical articular surface on the proximal end of a long bone

• Joins with the shaft of the bone at the neck region

Facet

• Flat articular surface

Projections

• Off a bone surface

Foramen

• Hole in a bone; may contain blood vessels, nerves

Fossa

• Depressed areas on the surface of a bone

Axial skeleton

• Bones of the head and trunk

• Bones of the “the main body mass”

Appendicular

• Bones of the limbs (extremities)

Axial skeleton

• Skull

• Hyoid bone

• Spinal column

• Ribs

• Sternum

Appendicular skeleton

• Thoracic limb (foreleg)

• Pelvic limb (rear leg)

Thoracic limb (proximal to distal)

• Scapula

• Humerus

• Radius

• Ulna

• Carpal bones (carpus)

• Metacarpal bones

• Phalanges

Skull

• Usually consists of 37 or 38 separate bones

Sutures

Most of the skull bones

Mandible

Is connected to the skull by a synovial joint