Osteogenesis Bone Growth and Formation

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Osteogenesis Bone Growth and Formation

• How
• Where
• When

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• The human skeleton consists of more than 200
  bones of varying size, shape, and composition.
• Is bone alive?

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• YES, bone is a dynamic, living tissue

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4 shapes

• long bones
• flat bones
• short bones
• irregular bones

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• GROWTH
• growth rate and bone length factors
• genetics
• circulating hormones
• nutritional intake
• disease

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• Bones grow longer from their ends
• Epiphyseal Growth Plate

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• a - Epiphyseal plate made of hyaline cartilage
  is responsible for long bone growth
• Note The direction of growth is toward the
  diaphysis (shaft of long bone).

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• a Rows of dividing and then enlarging of
  cartilage cells of the growth plate.
• b Region of calcification (ossification) of
  enlarged dead shells of cartilage cells to form
  spongy bone
• c Toward the epiphysis.
• d Toward the diaphysis

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FORMATION or REMODELING

• Bone remodeling occurs continuously throughout
  the lifetime, although the process slows with age

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OUCH!!

• Breaks
• and
• Fractures

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• 3 Cell Types
• Osteoblasts Osteocytes Osteoclasts

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• Osteoblasts - involved in bone
  
  formation
• Osteoclasts - involved
  in bone resorption. 

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• Osteoblasts that have been trapped in the mass
  produced by other surroundings osteoblasts are
  called Osteocytes.
• Osteocytes maintain bones they play a role in
  controlling the concentration of calcium and
  phosphate
• Osteoclasts secrete bone-reabsorbing enzymes,
  which digest bone matrix.

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• During childhood and the beginning of adulthood,
  bone becomes larger, heavier and denser
• Bone formation is then more important than bone
  resorption

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• When we are finished with puberty we stop growing
  because our hormones cause all of the cartilage
  within the epiphyseal disks to become ossified,
• HOWEVER..

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• Old bone is removed (resorption) and new bone is
  created (formation) constantly.