Bone Classification and Functions

Bone Classification

1. By Location

• Axial Skeleton:
  • Located along the body’s long axis
  • Includes:
    • Skull
    • Vertebral column
    • Ribcage
  • To be covered in Module 7
• Appendicular Skeleton:
  • Includes bones of the limbs (arms, hands, legs, and feet)
  • Connected to the axial skeleton by girdles (e.g., pelvis)
  • To be covered in Module 8
• Total: Approximately 206 named bones

2. By Shape

• Long Bones:
  • Longer than they are wide
  • Example: Humerus, limb bones, wrist, and ankle bones
• Short Bones:
  • Cube-shaped
  • Found in wrist and ankle
  • Sesamoid bones (e.g., embedded within tendons) sometimes categorized here
• Flat Bones:
  • Thin, possibly curved
  • Example: Skull bones, sternum (breast bone)
• Irregular Bones:
  • Complex shapes
  • Example: Coxal bones (pelvis), vertebrae

Functions of Bones

1. Support:
   • Provides structural support for body and organs
2. Protection:
   • Protects brain, spinal cord, and internal organs
3. Movement:
   • Muscles attached to bones function like levers
4. Mineral Storage:
   • Stores crucial minerals like calcium and phosphorus
   • 99% of body calcium is in bones
5. Blood Cell Formation (Hematopoiesis):
   • Occurs in red bone marrow
   • Produces red blood cells, white blood cells, platelets
6. Fat Storage:
   • Yellow marrow found in long bone shafts stores energy-rich fat
7. Hormone Production:
   • Produces osteocalcin, which regulates bone formation
   • Helps protect against obesity, glucose intolerance, and diabetes