Bone Structure and Extracellular Matrix

Extracellular Matrix

• Crucial for bone structure, including cartilage, tendons, ligaments, and bones.
• Collagen: Tough, rope-like protein providing strength (like steel in concrete).
• Mineral component: Provides compression strength (like concrete).
• Hydroxyapatite: Calcium phosphate crystals forming most of bone's mineral content.
• Proteoglycans: Large molecules with polysaccharides attached to proteins.
• Proteoglycan aggregates act like a "tree" structure, retaining water.

Classification of Bones

• Long Bones: Longer than wide, knobby ends for articulation.

  • Hollow shafts, solid ends.
  • Articular cartilage (hyaline cartilage) on ends for joints.
  • Curved structure for strength.
  • Examples: Arms, legs, fingers, toes.
  • Periosteum: Dense connective tissue covering the diaphysis (central shaft).
  • Endosteum: Thin epithelial membrane lining the medullary cavity.
  • Diaphysis: Central shaft of a long bone.
  • Epiphysis: Head of each end of a long bone.
  • Medullary Cavity: Marrow cavity containing yellow marrow.

• Short Bones: Equal length and width, nearly cube-shaped.

  • Example: Ankle and wrist bones.

• Flat Bones: Thin, providing protection and muscle attachment sites.

  • Example: Skull, sternum, ribs.

• Irregular Bones: Complex shapes.

  • Example: Face bones, vertebrae.

Functions of the Skeletal System

• Support: Supports and stabilizes soft tissues (muscles, blood vessels, nerves, fat, skin).
• Protection: Protects vital organs (brain, spinal cord, heart, lungs).
• Movement: Facilitates movement by providing attachments for muscles, acting as levers.
• Blood Cell Production: Hemopoiesis occurs in red bone marrow (a connective tissue within bone).
  • Produces red blood cells, white blood cells, and platelets.
• Storage: Stores mineral salts (especially calcium and phosphorus) and fats.
  • Yellow bone marrow: Primarily composed of adipose cells storing triglycerides (fats).
  • Red marrow transforms to yellow marrow with age.

Explore the role of the extracellular matrix in bone structure, including its components like collagen and hydroxyapatite. This quiz also covers the classification of bones with a focus on long bones and their anatomical features. Test your understanding of both the biological materials and the types of bones in the human body.