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Definition
| Ground substance is composed of inorganic material, calcium salts which combine to form hydroxyapatite. Additionally bone is made up of collagen fibers to allow greater flexibility. |
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Term
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Definition
| Immature bone cells primarily found on the outer and inner linings of the bone. Osteoid is the organic material the Osteoblast prodcue, along with collagen fibers. Osteoblasts deposit new bone under the periosteum causing what is called appositional growth. While laying down osteoid they become trapped in their own lacunae and differentiate into osteocytes. |
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Term
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Definition
| Mature bone cells, genetically differenitaited from osteoblasts. They are found in chambers calle lacunae, surrounded by layers of matrix called lamellae. Arising from each lacuna are mircoscopic channels called canaliculi for transporting waste and nutrients with the blood. |
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Term
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Definition
| Composed of densely packed osteons (Haversian Systems) that consist of osteocystes in lacunae sorounded by a matrix of lamellae that are like growth rings on a tree. Microscopic channels in the lacunae penetrate the lamellae allow the passage of waste and nutrients to the blood. |
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Term
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Definition
| Composed of a loose network of struts called trabeculae that contains dispersed osteocytes in lacuna. Between the struts are mesenchymal cells which produce red marrow that make red and white blood cells. |
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Definition
| large, multinucleated cells that are fairly undifferentiated. They are responsible for decomposing the bony matrix by secreting cids from their lysosomes. |
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Definition
| Microscopic tubes that penetrate the lamellae, they are tubes that exchange waste and nutrients between the osteocytes and the blood. |
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Term
| Central canal (Haversian Canal) |
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Definition
| A canal at the center of the osteon through which blood vessels and nerves travel. |
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Term
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Definition
| The outer covering of any bone, made of dense irregular connective tissue which becomes continous with ligaments. The inner layer is called the cellular layer and is composed of many fibroblasts and many osteoblasts that lay bone externally (appositional growth) thereby making the one thicker. |
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Term
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Definition
| A single layer of simple epithelial tissues believed to cover the trabeculae, the central canal, and the medular cavity. |
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Term
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Definition
| Directly beneat the periosteum, in a long bone it is thickest in the diaphysis (shaft) and surrounds the yellow marrow (mostly adipose) which fills the medullary cavity. The compact bone thins out at the epiphyses (end/head) of the bone. In a flat bone it is located in the tables (dorsal and ventral surfaces) of the bone. |
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Term
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Definition
| Loose network of trabeculae primarily found in the epiphyses of long bones and to a lesser extent in the medullary cavity of the diaphysis of long bones. In flat bones is is sandwiched between the tables and is called diploe. |
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Term
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Definition
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Term
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Definition
| the organic matrix of bone before it is mineralized with calcium and phosphate salts. Osteoid it primarily collagen fiber produced by osteoblasts. |
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Term
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Definition
| conversion of tissue into bone. |
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Term
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Definition
| the deposition of calcium salts in a tissue. during calcification of bone, the salts form crystals of hydroxyapatite which strengthens the bone and make it hard. The salts primarily are made of calcium hydroxide and calcium phosphate. |
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Term
| Importance of vitamins A & C |
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Definition
| Vitamins A & C are necessary for collagen production, these vitamins must be obtained from the diet. |
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Term
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Definition
| Vitamin D is necessary for proper absoprtion of calcium from the digestive system. Exposure of the skin to the suns UV rays can enable our bodies to produce vitamin D our we can obtain it from our diet. |
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Term
| Importance of growth, Thyroid hormones. |
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Definition
| Growth and thyroid hormones increase metabolism. They stimulate the epiphyseal plate cartiligeof long bones during childhood and adolescence. |
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Term
| Importance of sex hormones |
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Definition
| Sex hormones enhance growth by stimulating the activity of osteoblasts which causes the bone tissue to be laid down faster than the epiphyseal plate can grow, thus causing the plate to seal up. Once this occurs in a long bone, the growth in length of the bone will cease. |
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Term
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Definition
| reduction in bone growth or inadequate bone growth, typically experienced in people over 40 years old. |
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Term
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Definition
| reduction in bone mass which compromises the integrity of the bone and may lead to an increased chance of fracture or collapse. |
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| Functions of skeletal system |
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Definition
| support the body, create leverage during movement, storage of lipids and minerals; blood cell production, protection. |
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Term
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Definition
| spongy bone sandwiched between the tables of flat bones |
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Term
| Intramembrenous Ossification |
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Definition
| During fetal development the dense irregular fibrous connective tissue is invaded by mesenchymal cells. The mesenchymal cells differentiate into osteoblasts which lay down osteoid just under the skin. Spongy one is initially formed, followed by compact bone. This process primarily occurs in flat bones. |
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Term
| Endochondrial Ossification |
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Definition
| Bones begin as hyaline cartilage models. During fetal developlment the perichondrium is infiltrated with blood vessels which allow osteoblasts to enter the cartilaginous bone. A periosteom is formed, the cartilage in the center begins to die and the primary center of ossification is formed. Osteoclasts then break down the spongy bone to form the medullary cavity. The secondary site of ossification is formed at the epiphyses, the twoo grow towards each other at the epihpyseal plate. |
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Term
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Definition
| major arteries and veins are found entering the diaphysis and epiphysis in long bones. All bones have major arteries penetrating them. All bones also exhibit periosteal blood vessels supplying the outer layers of a bone. |
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Term
| Differences between male skull and female skull |
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Definition
| Male skull is heavier; rougher appearance. Forehead is more sloping. Sinuses, mandible, and teeth are larger. Female skull is lighter; smoother surface. More vertical forehead. |
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Term
| Skeletal differences between male and female |
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Definition
| bones are heavier and markings are more prominent in male skeletons. |
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Term
| differences in skeletal system among different age groups |
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Definition
| Reducion in mineral content at age 3045, values differ for male vs. female, similiar reduction after age 65. Fetal skulls have fontanels which close by age two. Styloid process fuses with temporal bone by age 12-16. Hyoid bone completely ossified by age 25-30. Epiphyseal cartilage is fused by adulthood. |
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