Question

What is a Haversian Canal?

Answer 1

Hint: Haversian canals were first discovered and explained by British physician Clopton Havers. They were described in his work Osteological Nova which was published in 1691.

Complete answer:
Haversian canals are a series of microscopic tube-like structures in bone that contain nerve fibers and capillaries. The presence of Haversian canals enables the bone to receive oxygen and nutrition without the need of being vascular. Haversian canals play a major role in bone strength as they actively work towards the deposition of mineral salts in the bone. Deposition of minerals in bone is performed with the help of special canaliculi. Communication with the canaliculi facilitates bone deposition.
A single Haversian canal usually consists of a couple of capillaries and several nerve fibres. A Haversian canal is formed by concentric layers of the bone called lamellae and are based inside osteons. The diameter of the lamellae is approximately 45μm. Osteons or Haversian systems are cylindrical structures of the bone. Their main function is the transport of oxygenated blood to bone. They are parallel along the axis to the surface of the bone. The transport of most substances between the bone and the blood is conducted through the process of active transport.

Note:
Haversian canals together with osteons form the Haversian system which is the main functional unit and transports oxygen and minerals through the blood to the bone.
A bone fracture is most likely to damage the blood vessels in the Haversian canal which can lead to Haematoma which is bleeding outside of blood vessels.
Patients suffering from rheumatoid arthritis may have wider Haversian canals and they are more likely to contain osteoclasts which damage the bone structure and break it down.