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| Produce and maintain cartilaginous matrix found in cartilage. They are derived from immature chondroblasts |
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| Fibrocartilage allows the bone to extend. As when being pulled from both sides |
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| Fibrocartilage allows the organ to compress. As if being pushed inward from both sides |
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| Lamalae running in opposite directions allow for resistance to this torsion, or twisting inwardly on itself |
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| The long part of the bone. From outside to inside, contains the Periosteum, compact bone, endosteum, and marrow cavity. Provides leverage to teh bone |
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| The head at each end of the bone. Separated from the diaphysis by the epiphysis plate. Contains red bone marrow found between the trabeculae. Articular cartilage surrounds it. |
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| Separates the marrow of diaphysis from the epiphysis. This is the zone where the bone grows longitudinally. Turns into a line in adults. Consists of hyaline cartilage in the middle, outsides being replaced by bone. |
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| Part of the diaphysis that contains the yellow marrow/red marrow in children. Red marrow is hemopoietic, or produces red blood cells. Yellow marrow no longer produces blood, but can in the case of anemia. |
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| The outer portion of the bone derived from early cartilage. Inner layer contains osteoblasts and osteocytes that regulate bone matrix. Outer layer contains fibroblasts. Supplies body with nutrients and senses torque. |
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| Thin layer of connective tissue in the inner diaphysis made up of osteoblasts and osteocytes. Can be reabsorbed in times of malnutrition. |
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| Basic repeating unit found in the compact bone. Comprised of bone matrix (lamallae) concentrically arranged around central canals (havarian canals) that contain blood vessels and nerves. Havarian canals are connected by Volkmann canals |
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| Line the periosteum inner layer and the endosteum. Secrets the bone matrix, nonmitotic. Secrete osteocalcin which limits the growth of adipose tissue |
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| Bone-dissolving cells found on the bone surface. Formed from the fusion of several stem cells (usually large). Have highly developed lysosomes and increase cell surface area. Found in reabsorption bays. |
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| Former osteoblasts that have become trapped in the bone matrix. Reside in lucunae, and communicate with fellow cells using cytoplasmic processes. Communicate through gap junctions. Both reabsorb/dissolve matrix, sense strain. |
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| Surrounds the epiphysis on the end of the bone. This is the joint area where one bone meets another. |
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| Endochondral ossification |
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| The bone develops from a preexisiting model of hyaline cartilage (6th week of fetal development). 4 steps- 1.Formation of primary ossification center through chondrocyte enlargement (from lacunae merging). Osteoblasts begin to form 2.Blood vessels penetrate matrix carrying osteoblasts that form bone matrix. Spongy bone forms. 3. Invasion of Epiphyseal blood vessel, 2nd ossification center forms. Marrow cavity begins to form. 4. Spongy bone in epiphysis forms, forming marrow cavity there. Cartilage limited to epiphyseal plate and articular surface. |
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| Calcium salts build up in soft tissue deposited by lacunae. Not permanent deposits, but temporary support for cartilage that would otherwise breakdown. Lacking this leads to soft, easily bending bones |
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| Secreted by the parathyroid gland when the blod calcium is low, reaches osteoclasts, and leads to an increase of blood calcium levels through higher production of osteoclast production |
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| Secreted by C cells of Thyroid gland when blood calcium concentration is too high. Leads to bone deposition by inhibiting the production of osteoclasts and stimulation of osteoblasts. |
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| plays roles in communication among neurons, muscle contraction, blood clotting, and exocytosis, also second messenger for cell-signaling. Skeleton acts as a resovoir for this. 99% trapped in bones, 1% exchangable with blood. |
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| Loss of bone density due to bones being dominated by osteoclasts rather than osteoblasts. Leads to brittle nature and porous bones, |
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| Bones in children become abnormally long and soft. Predominant cause is lack of vitamin D, soft bone nature is caused by calcium and phosphate levels in blood being too low. This is a result of deficient levels of calcitrol in the blood. |
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