Haversian system

Haversian system or osteon is the fundamental functional unit of much compact bone. Osteons are cylindrical structures that contain a mineral matrix and living osteocytes connected by canaliculi, which transport blood. They are aligned parallel to the long axis of the bone. Each osteon consists of concentric layers, or lamellae, of compact bone tissue that surround a central canal, the Haversian canal.

Structure

The Haversian canal contains the bone's blood supplies. The boundary of an osteon is the cement line. Each Haversian canal is surrounded by varying number (5-20) of concentrically arranged lamellae of bone matrix. While the osteon may be the primary anatomical and functional unit of the compact bone, the osteocyte, its cell, and the canaliculi, the osteocyte's arms, are the primary anatomical and functional units of the bone.

Function

The Haversian systems are responsible for the provision of nutrients and the removal of metabolic waste products. Osteocytes, the living cells of bone tissue, are located inside of the Haversian system. They communicate with each other and receive nutrients via long cytoplasmic processes that extend through canaliculi, which are channels within the bone's calcified matrix.

Clinical significance

In humans, the remodeling of Haversian systems can be used to determine age, diet, and health history. For example, the analysis of osteons in a population can reveal information about the population's diet, age, and disease history.

See also

• Bone
• Osteocyte
• Canaliculi
• Lamellae
• Compact bone

References

Haversian system Resources
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