Supporting CT bone tissue

Compact bone

• Outer layer of bone, forms shaft of long bones

• Also known as cortical bone

• composed of many rod shaped unites known as osteons/haversian systems

• Stores calcium + phosphorus

• Protection + support

Four cell types

• Osteogenic

• Osteoblasts

• Osteocytes

• Osteoclasts

Structure of Haversian Systems

• Lamallae

• Lacunae

• Canaliculi

• Central (Haversian) canal

Lamallae

concentric rings of mineral salts for hardness (e.g. calcium phosphate and calcium hydroxide, which together form hydroxyapatite) and collagen (for tensile strength)

Lacunae

small spaces between lamellae that contain mature bone cells (osteocytes)

Canaliculi

“minute canals” (containing EC fluid and minute osteocytic processes) that radiate from lacunae and provide routes for oxygen, nutrients and waste

Central (Haversian) canal

Blood, lymph + nerves

Spongy bone

• Porous inner bone tissue lying under compact bone

• known as cancellous bone

• Lacks osteons

• Stores triglycerides (yellow marrow) + produces RBC (red marrow)