HAVERSIAN SYSTEM IN MAMMALS - MBBS PDF Download

Haversian system : A haversian canal, its lamellae and osteocytes form a haversian system. Haversian canals are found in bone matrix of long bone, like humerus of mammals. Haversian canals contain artery and veins, osteoblasts in areolar tissue, nerves and lymph. It is also called osteon.There is no regular Haversian system so bones have spongy texture.

The compact bone region of mammalian bone contain along with above written structures a system of canals called Haversian and Volkmann’s canals. These canals contain an arteriole a venule and nerve fiber. The requirement of such a system in mammalian bones is seen due to large size of mammalian bone as the result of which the superficial supply of blood vessels is insufficient in providing essential requirements of life to osteocytes. The harversian canals are vertical canal present parallel to the length of bones. Haversian canals 4-20 concentric ring of lamella normally surround one Haversian canal. This complete system of lamella along with one Haversian canal is called one osteon. In a bone these osteons are separated by specialized bright thin line called cementing line of ebner. Presence of Haversian system is the characteristic feature of mammalian bone. Haversian system shows Haversian canal in the centre. Haversian canal consists of blood vessels as both artery and vein, lymph vessel and a nerve. Lacunae containing osteoblasts or osteocytes are seen arranged concentrically around Haversian canal. The two adjacent Haversian systems are inter connected by Volkmann's canal.

Haversian zone:-The Haversian canal and their related lamellae in 4-20 concentric layers around them .This zone is also called as zone of osteons.

Interstitial zone:-This is present between the Haversian zone is certain lamellae called interstitial lamellae. These lamellae along with their lacunae come under this zone