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Haversian canals [i] (sometimes canals of Havers, osteonic canals or central canals) are a series of microscopic tubes in the outermost region of bone called cortical bone. They allow blood vessels and nerves to travel through them to supply the osteocytes .
Each osteon consists of concentric layers, or lamellae, of compact bone tissue that surround a central canal, the Haversian canal. 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.
Volkmann's canals, also known as perforating holes or channels, are anatomic arrangements in cortical bones that allow blood vessels to enter the bones from periosteum. They interconnect the Haversian canals (running inside osteons ) with each other and the periosteum.
Armand de Ricqlès discovered Haversian canals in dinosaur bones, and argued that there was evidence of endothermy in dinosaurs. These canals are common in "warm-blooded" animals and are associated with fast growth and an active life style because they help to recycle bone to facilitate rapid growth and repair damage caused by stress or ...
In bovine tibia diameter of canaliculi was found to vary from 155 to 844 nm (average 426 nm). [2] In mice humeri it varies from 80 to 710 nm (average 259 nm), while diameter of osteocytic processes varies from 50 to 410 nm (average 104 nm).
X 100. a, Haversian canals; b, lacunae seen from the side; c, others seen from the surface in lamella, which are cut horizontally. Nucleated bone cells and their processes, contained in the bone lacunae and their canaliculi respectively.
Havers' thesis. Clopton Havers (24 February 1657 – April 1702) was an English physician who did pioneering research on the microstructure of bone. He is believed to have been the first person to observe and almost certainly the first to describe what are now called Haversian canals and Sharpey's fibres.
The highest area in Georgia is Brasstown Bald which is 1,458 m (4,783 ft) above sea level, while the lowest is at sea level, at the Atlantic Ocean. Georgia is located at approximately 33° N 83.5° W. The state has a total area of 154,077 km 2 (59,489 sq mi) and the geographic center is located in Twiggs County. [3]