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In osteology, the osteon or haversian system (/ h ə ˈ v ɜːr. ʒ ən /; named for Clopton Havers) is the fundamental functional unit of much compact bone. Osteons are roughly cylindrical structures that are typically between 0.25 mm and 0.35 mm in diameter . [ 1 ]
Human bones are densely vascularized as in many other mammals. Even though some authors tried to identify a correlation between endothermy and secondary Haversian reconstruction, this feature is absent in many living mammals (e.g. monotremes, Talpa, flying foxes, Herpestes, Dasypus) and birds (Aratinga, Morococcyx, Nyctidromus, Momotus, Chloroceryle) while others possess only scattered ...
Crack deflection and twist occurs due to osteons, the structural unit of cortical bone. Osteons have a cylindrical structure and are approximately 0.2 mm in diameter. As the crack tip reaches an osteon, crack propagation is deflected along the lateral surface of the osteon slowing crack growth.
The heart's cardiac skeleton comprises four dense connective tissue rings that encircle the mitral and tricuspid atrioventricular (AV) canals and extend to the origins of the pulmonary trunk and aorta. This provides crucial support and structure to the heart while also serving to electrically isolate the atria from the ventricles. [1]
They are located on the surface of osteon seams and make a protein mixture known as osteoid, which mineralizes to become bone. [23] The osteoid seam is a narrow region of a newly formed organic matrix, not yet mineralized, located on the surface of a bone. Osteoid is primarily composed of Type I collagen.
Within chromosomes, DNA is held in complexes with structural proteins. These proteins organize the DNA into a compact structure called chromatin. In eukaryotes, this structure involves DNA binding to a complex of small basic proteins called histones, while in prokaryotes multiple types of proteins are involved.
Inside of a bone showing the trabecular structure A typical carcinoid tumor of the lung showing a trabecular pattern of elongated groups of cells.. A trabecula (pl.: trabeculae, from Latin for 'small beam') is a small, often microscopic, tissue element in the form of a small beam, strut or rod that supports or anchors a framework of parts within a body or organ.
The skeleton, often referred to as the skeletal system, is important both as a supporting structure and for maintenance of calcium, phosphate, and acid-base status in the whole organism. [5] The functional part of bone, the bone matrix, is entirely extracellular. The bone matrix consists of protein and mineral. The protein forms the organic matrix.