Describe the cross section of a compact bone

General
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describe the cross section of a compact bone

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Describe the cross section of a compact bone

Answer:

The cross section of a compact bone reveals its dense and organized structure, which is crucial for providing strength and support to the skeletal system. Here’s a detailed description of the main components visible in a cross section:

Structure of Compact Bone:

  1. Osteons (Haversian Systems):

    • These are cylindrical structures that run parallel to the long axis of the bone, playing a key role in the bone’s structural integrity.
    • Each osteon consists of concentric layers, or lamellae, of calcified matrix.

  2. Central (Haversian) Canal:

    • Located in the center of each osteon, this canal contains blood vessels and nerves, supplying nutrients and oxygen to bone cells.

  3. Lamellae:

    • The concentric rings of matrix surrounding the central canal are composed of collagen fibers and mineral salts, which provide strength and resilience.

  4. Lacunae:

    • Small spaces between lamellae that house osteocytes (mature bone cells). These cells maintain the bone tissue.

  5. Canaliculi:

    • Tiny channels that connect lacunae to each other and the central canal. They allow for the exchange of nutrients and waste products between osteocytes and blood vessels.

  6. Perforating (Volkmann’s) Canals:

    • These canals run perpendicular to the central canals, linking them with the periosteum and medullary cavity, facilitating blood and nerve supply.

  7. Interstitial Lamellae:

    • These are the remnants of older osteons that have been partially resorbed during bone remodeling.

  8. Circumferential Lamellae:

    • Layers of bony matrix that encircle the entire bone shaft, located just beneath the periosteum and lining the medullary cavity.

Functional Significance:

  • The compact bone’s layered and concentric organization provides substantial mechanical support and resistance to stress. This allows the skeleton to withstand compressive forces and protect internal organs effectively.

In summary, the cross section of a compact bone reveals a highly organized structure made up of osteons, central canals, and various types of lamellae, all working in harmony to ensure the bone’s strength and functionality.