Skeletal System

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Skeletal System

• Milk.. It does do the body GOOD!

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Specialized Cells found in Osseous Tissue

• Bone Cells
• Osteocytes
• Living bone cells embedded in the mineralized
  (abiotic) matrix
• Maintain the density and composition of bone.
• Vascularization of Bone?????
• Osteoblasts
• Build bone by producing mineralized matrix
• When osteoblasts become surrounded by bone they
  become osteocytes.
• Osteoclasts
• Break down the mineralized matrix of bone.
• Their activity releases the stored minerals into
  the blood.

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Osteoclasts

• Osteoclasts lie in Howship's lacuna
• formed from the digestion of the underlying bone
• How does this digestion take place?
• osteoclast releases hydrogen ions (H2O CO2 ?
  HCO3- H)
• acidifying and dissolving the mineralized bone
  matrix into Ca2
• collagenase released

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Osteoclasts

• Use in orthodonture
• Osteoclastic activity
• basis for straightening of the teeth with dental
  braces
• The pressure exerted on the tooth causes
  micro-fractures
• osteoclasts absorb the fractured bone
• Osteoblasts then re-grow the bone to coincide
  with less pressure on the tooth, thus
  manipulating the orientation of the tooth.

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Name the Cell
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Compact Bone

• Osteons
• the basic functional units of compact bone.
• Osteons are also called Haversian Systems.
  
• Osteons are comprised of the following
• Lamellae
• rings of mineralized matrix
• Lacunae
• small cavities within bone
• osteocytes are located within lacunae
• Canaliculi
• small canals that link the lacunae to blood
  vessels.
• Central canal or Haversian canal
• Located at the center of each osteon
• The canal contains blood vessels and nerves that
  run parallel to the long axis of the bone.

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Anatomy of Compact Bone

• Periosteum
• Osteons
• Canaliculi
• Haversians Canals
• Volkmans Canals
• Lamella
• Lacunae

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Lacunae and Canaliculi
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Haversian and Volkmans Canals
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Periosteum and Endosteum
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??Questions on Compact Bone??
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Spongy or Cancellous Bone
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Spongy Bone

• Trabeculae
• Note geometric structures formed
• What do these structures accomplish that compact
  bone can not?
• If you understand A/P of compact bone and the
  previous question, you understand the need for
  spongy bone!

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Bone Formation

• Bone Collar
• Compact Bone
• Medial
• Cancellous or Spongy Bone
• Bi-Lateral to compact
• Calcified Cartlidge
• Bi-Lateral to spongy
• Un-calcified Cartlidge
• Bi-lateral to Calcified Cartlidge
• Perichondrium
• Developing connective tissue
• Becomes periosteum

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Bone Formation
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Bone Formation
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Red Bone Marrow