Chapter 6Bones and Skeletal Tissues

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Chapter 6-Bones and Skeletal Tissues

• Histology of cartilage and bone
• Function of the skeletal system
• Bone terminology
• Bone development and growth

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The skeletal system is multifunctional

• Support
• Storage of minerals and lipid
• Blood cell proliferation (red marrow)
• Protection (heart, etc.)
• Leverage, Movement

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Cartilage Connective tissue

• Chondroblasts lay down the matrix,
• become chondrocytes when surrounded by EC matrix
• Chondrocytes do not mitose
• Poor healing
• On aging, cartilage becomes calcified
• Less flexible
• Not bone

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Cartilage, contd

• Elastic More flexible, e.g., ear

Hyaline Especially articular
Fibrocartilage Resists compressionIV Disk,
menisci
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Types (shapes) of Bones

• Long
• Femur
• Short
• Carpal
• Sesamoid
• Patella

• Flat
• Scapula
• Sutural
• Skull
• Irregular
• Vertebra

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Typical (Long) Bone Structure
Page 129
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Bone markings Table 6.1

• Projection and Process
• Tuberosity, tubercle
• Trochanter (only one!)
• Lines and spines
• Epicondyles
• Surfaces for Joints
• Head, facet, condyle
• Depressions and holes
• Foramen
• Fossa

• Mostly a lab exercise

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Types of Osseous Tissue

• Compact Bone
• Dense, found in the walls, or cortex
• Spongy or Cancellous Bone
• Network of struts and thin plates (trabeculae)
• Marrow
• Red and Yellow

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1. Compact Bone

• Osteon functional unit of bone
• The mineral matrix is hydroxyapatite
• Osteoblasts lay down the matrix in layers
  (lamellae)
• Become osteocytes when surrounded by EC matrix
• Lacunae
• Osteoclasts break down bone

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2. Spongy Bone

• No osteons
• Lacy network of struts called trabeculae
  reinforce the bone
• Covered by endosteum

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3. Marrow

• Red Marrow
• Active
• Blood Precursors
• Yellow Marrow
• Inactive
• Mostly fat

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Internal Organization of a Typical Bone
p 133
Osteon Functional unit of bone
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Bone Development

• Osteoblasts produce hydroxyapatite
• Osteoclasts break down the hydroxyapatite
• Intramembranous Ossification
• Plates of Bone e.g. skull
• Endochondral Ossification
• Long Bones

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Intramembranous Ossification
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Endochondral Ossification
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Endochondral Ossification
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Bone Circulation
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Bone Remodeling

• Bones are metabolically very active
• Osteoid becomes hydroxyapatite
• Source for calcium

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Fractures

• Young vs. old patients
• Simple vs. open (compound) fractures
• Healing
• Reduction and stabilization
• Formation of hematoma
• Callus
• fibrocartilagenous and
• bony
• Remodelingmonths later

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Osteoporosis (p 141)

• Loss of bone mass weakness
• Both compact and spongy bone
• Post-menopausal women, some men
• Estrogen replacement??

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Osteoporosis (p 141)
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