Functions of the Human Skeleton

Protection

  • The skeleton provides protection to internal organs and structures.
  • Bones are hard and strong, capable of withstanding impacts and repairing themselves.
  • Example: Ribs protect the heart and lungs.

Support

  • The skeleton provides a rigid structural framework that supports posture.
  • It enables standing and maintains body position.

Movement

  • Skeletal muscles attach to the skeleton, facilitating movement.
  • Skeletal muscles contract to move the bones.
  • Without muscles, the skeleton cannot move.

Mineral Storage

  • Bones store minerals such as calcium and phosphates.
  • These minerals can be released into the blood as needed for various functions.
  • Example: Calcium is used for neuronal function.
  • Bone composition is affected by mineral intake; increased calcium intake can lead to denser bones.

Blood Cell Formation (Hematopoiesis)

  • Blood cells are formed in the bone marrow.
    • Red bone marrow: Responsible for blood cell formation (erythrocytes, monocytes, neutrophils, eosinophils).
    • Yellow bone marrow: Involved in fat production and energy storage.
    • Red bone marrow is typically found at the ends of long bones and in flat bones.

Detailed Look at Skeletal Functions with Examples

  • Protection:

    • The skull protects the brain.
    • The vertebral column protects the spinal cord.

  • Stability and Movement:

    • Bones provide a rigid framework for posture and stability.
    • Muscles are required for movement. Muscle wasting affects movement.
    • Example: Biceps brachii muscle contraction enables movement of the humerus, radius, and ulna.

  • Bone Mineral Composition

    • Bones are composed of both organic and inorganic materials.
      • Organic substances include collagen fibers, produced by the body.
      • Inorganic substances such as calcium and phosphorus are obtained from diet (e.g., grass, lettuce, steak).
      • Calcium is vital for nerve firing and muscle contraction.
      • Bone remodeling is the process of cells adding to or removing minerals from bone to maintain mineral balance (homeostasis).
      • Imbalances can lead to conditions like osteoporosis (not enough bone) or osteopetrosis (too much bone).

  • Cell Formation and Energy Storage

    • Red bone marrow carries out hematopoiesis, producing red blood cells and other blood cells.
    • Red bone marrow is located in the spongy bone (trabecular bone) at the ends of long bones (e.g., femur) also know as the epiphysis and in flat bones.
    • Yellow bone marrow, located in the medullary cavity (shaft) of long bones, stores fat and can produce ATP for energy.