Lecture Notes on Bone Structure and Anatomy

Introduction

• Professor Dave discusses the structure of bones and their types.
• Bones are part of connective tissue.

Skeletal Cartilage

• Cartilage Characteristics:
  • Contains water, aiding in tension and compression resistance.
  • Comprised of chondrocytes in lacunae within an extracellular matrix.
  • Three types: hyaline, elastic, fibrocartilage.

Types of Cartilage

• Hyaline Cartilage

  • Most common skeletal cartilage.
  • Locations: nose, ribs, larynx, ends of bones.
  • Function: provides support.

• Elastic Cartilage

  • Stretchier type, found in ears and epiglottis.

• Fibrocartilage

  • Highly compressible, found between vertebrae.

Bones Overview

• Categories of Bones:
  • Axial Bones: head and torso, including spine, rib cage, skull.
  • Appendicular Bones: limbs, pelvis, shoulders.

Bone Classification by Shape

• Long Bones: longer than wide (e.g., limbs).
• Short Bones: cube-like (e.g., ankles, wrists).
• Flat Bones: thin, often curved (e.g., sternum, shoulder blades).
• Irregular Bones: complex shapes (e.g., vertebrae, hip bones).

Functions of Bones

• Support bodily structure.
• Protect organs (e.g., rib cage protects heart).
• Act as levers for movement.
• Provide mineral and fat storage.
• Produce blood cells and hormones.

Bone Composition

• Bone as a Tissue vs. Organ:
  • Composed of bone tissue, nervous tissue, connective tissue, cartilage, blood vessels.

Gross Anatomy of Bones

• Compact Bone: dense outer layer.
• Spongy Bone: internal honeycomb structure filled with marrow.
• Bone Types have unique arrangements of compact and spongy bone.

Long Bones

• Diaphysis: tubular shaft, compact bone surrounding medullary cavity with yellow marrow.
• Epiphyses: ends with spongy bone inside.
• Red Marrow: produces blood cells.
• Periosteum: membrane covering bone exterior, containing fibrous and osteogenic layers.
• Endosteum: covers internal bone surfaces.

Microscopic Anatomy of Bones

• Cell Types:
  • Osteogenic Cells: stem cells in periosteum and endosteum.
  • Osteoblasts: secrete bone matrix, responsible for growth.
  • Osteocytes: mature cells maintaining the matrix.
  • Bone Lining Cells: maintain the matrix on the bone surface.
  • Osteoclasts: break down bone, releasing minerals.

Compact Bone Structure

• Osteons: cylindrical units with central canals.
• Lamellae: layers of bone matrix around canals.
• Canaliculi: tiny canals connecting lacunae.
• Interstitial and Circumferential Lamellae: fill gaps and surround osteons.

Chemical Composition of Bone

• Organic Components: cells and osteoid (ground substance and collagen).
• Inorganic Components: hydroxyapatites (calcium phosphate crystals).
• Contribution to bone strength, flexibility, and resilience.

Conclusion

• Overview of how bone structure contributes to the formation of the human skeleton.