Structure of short, irregular, and flat bones

• No diaphysis or epiphyses

• Covered compact bone on the outside with endosteum

• Covered spongy bone on the inside

• Thin plates of periosteum

• Contains bone marrow between the trabeculae

Osteogenic

• “Osteoprogenitor cells” (stem cells)

• Bone forming cells

• Mature bone cells

• Large cells that reabsorb or breakdown bone matrix

Tags

NGSS.HS-LS1-4

Osteoblasts

• Stem cells

• Part of the matrix that contains ground substance and collagen fibers

• Mature bone cells

• Bone forming cells

Osteocytes

• Stem cells

• Bone forming cells

• Mature bone cells

• Part of the matrix that contains ground substance and collagen fibers

Osteoclasts

• Stem cells

• Large cells that reabsorb or breakdown bone matrix

• Bone forming cells

• Part of the matrix that contains ground substance and collagen fibers

Osteoid

• Part of the matrix that contains ground substance and collagen fibers

• Stem cells

• Mature bone cells

• Large cells that reabsorb or breakdown bone matrix

Inorganic components of bone

• Responsible for 92% of bone mass

• Responsible for bone hardness and it’s resistance to compression

• Mainly calcium phosphates

• 65% of bone mass

• Hydroxyapatites or bone salts

Osteon (Haversian System)

• Central channel containing blood vessels and nerves

• Weight-bearing, column-like matrix tubes composed mainly of collage

• Basic unit of compact bone

• Mainly calcium phosphates

Lamella

• Basic unit of compact bone

• Connect blood and nerve supply of the periosteum to that of the Haversian Canal

• Central channel containing blood vessels and nerves

• Weight-bearing, column-like matrix tubes composed mainly of collage

Haversian Canal

• Connects blood and nerve supply of the periosteum to that of the Haversian Canal

• Central channel containing blood vessels and nerves

• Basic unit of compact bone

• Calcium phosphates are made from here