Search results
Results from the WOW.Com Content Network
Each Haversian canal generally contains one or two capillaries and many nerve fibres. The channels are formed by concentric layers called lamellae , which are approximately 50 μm in diameter . The Haversian canals surround blood vessels and nerve cells throughout bones and communicate with osteocytes (contained in spaces within the dense bone ...
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.
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.
The single canal found in hagfish appears to be secondarily derived. Additionally, the vestibular systems of lampreys and hagfish differ from those found in other vertebrates in that the otolithic organs of lampreys and hagfish are not segmented like the utricle and saccule found in humans, but rather form one continuous structure referred to ...
The cardiovascular centre affects changes to the heart rate by sending a nerve impulse to the cardiac pacemaker via two sets of nerves: sympathetic fibres, part of the autonomic nervous system, to make heart rate faster. the vagus nerve, part of the parasympathetic branch of the autonomic nervous system, to lower heart rate.
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.
It consists of multiple microscopic columns, each called an osteon or Haversian system. Each column is multiple layers of osteoblasts and osteocytes around a central canal called the osteonic canal. Volkmann's canals at right angles connect the osteons together. The columns are metabolically active, and as bone is reabsorbed and created the ...