Term
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Definition
| cuboidal to columnar bone building cells |
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Term
| what do osteoblasts deposit which becomes calcified bone? |
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Definition
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Term
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Definition
| mature bone maintaining cells trapped in lacunae |
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Term
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Definition
| large multinucleated cells responsible for bone resorption |
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Term
| what 3 hormones regulate calcium phosphate homeostasis? |
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Definition
| PTH, calcitonin, calcitriol (vitamin D) |
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Term
| what effect does PTH have on bone resorption? |
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Definition
| increases bone resorption, raises serum calcium levels (has also been seen to lower bone resorption but mechanism is unknown) |
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Term
| how does PTH increase bone resorption? |
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Definition
| binds to receptors on osteoblasts. osteoblasts then secrete osteoclast stimulating factor which binds to osteoclasts and activates them |
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Term
| what effect does calcitonin have on bone resorption? |
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Definition
| inhibits osteoclasts so decreased bone resorption which prevents calcium release from bone (decreased serum calcium) |
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Term
| what effect does vitamin D have on calcium? |
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Definition
| increases calcium absorption in the gut, increases bone resorption taking calcium and phosphate from old bone in order to mineralize new bone |
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Term
| effect of calcitriol on bone? |
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Definition
|
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Term
| effect of calcitriol of kidney? |
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Definition
| reduced excretion of calcium |
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Term
| effect of calcitriol on gut? |
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Definition
| absorption of calcium and phosphate |
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Term
| who is at greatest risk of osteoporosis? |
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Definition
|
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Term
| what effect does estrogen have on bone? |
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Definition
| maintains bone density in both sexes, it inhibits bone resoprtion |
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Term
| what is the predominant structural protein in bone? |
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Definition
|
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Term
| what is the form of calcium and phosphate in the collagen and ground substance of bone? |
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Definition
|
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Term
| what do bone morphogenic proteins (BMPs) do? |
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Definition
| induce the differentiation of mesenchymal cells into osteoblasts |
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Term
| what is the shaft of the long bone termed? |
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Definition
|
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Term
| what are the proximal and distal ends of the long bone termed? |
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Definition
|
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Term
| where is the epiphyseal line? |
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Definition
| between the metaphysis and the epiphysis |
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Term
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Definition
| a fibrous connective tissue that surrounds the outer surface of the non articulating parts of the bone |
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Term
| what is the source of the pain from a bone fracture? |
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Definition
|
|
Term
| nutrient vessels enter the bone through what? |
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Definition
|
|
Term
| where is red bone marrow typically found in adults? |
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Definition
| the sternum and iliac crest |
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Term
| what are the sternum and iliac crest typically used for clinically? |
|
Definition
| sites for biopsy and marrow transplantation |
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Term
| what is yellow bone marrow? |
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Definition
| fatty marrow that can convert to red marrow if need be |
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Term
| concentric lamellae and the haversion canal constitutes the? |
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Definition
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Term
| what are the result of bone remodeling and lie between complete osteons? |
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Definition
|
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Term
| what are the two parts of the periosteum? |
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Definition
| out fibrous layer (dence CT) and inner cellular layer (osteoprogenitor cells) |
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|
Term
| where does the endosteum line? |
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Definition
| internal surfaces; has a thin layer of osteoprogenitor cells |
|
|
Term
| what are sharpey's fibers? |
|
Definition
| collagen fibers found at the site of a tendon insertion into bone; these fibers run through the periosteum and are continuous with the collagen fibers of bone tissue |
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|
Term
| what are caniculi and how do they communicate? |
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Definition
| small canals allowing extended cytoplasmic processes of an osteocyte trapped in lacunae to make contact with other osteocytes and communicate via gap junctions |
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|
Term
| what is the center of the haversion system lined with? |
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Definition
|
|
Term
| what is the orientation of haversion systems? |
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Definition
|
|
Term
| what is the orientation of volkman's canals? |
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Definition
|
|
Term
| where is the outer circumferential lamellae located? |
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Definition
|
|
Term
| where is the inner circumferential lamellae located? |
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Definition
|
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Term
| describe the difference between immature (woven) bone and mature (lamellar) bone |
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Definition
| immature has more cells and the matrix is not layered while mature has fewer osteocytes per unit area and has osteons with concentric lalellae with the presence of interstital lamella |
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|
Term
| where is primary bone typically found in adults? |
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Definition
| tooth sockets, near the sutures of the flat bones of the skull and the insertions of some tendons |
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Term
| what is the purpose of the ruffled border made by the osteoclast? |
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Definition
| dramatically increases surface area |
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|
Term
| the depression made in bone by the osteoclast is termed what? |
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Definition
|
|
Term
| what is contained in the organic (osteoid) region of bone matrix? |
|
Definition
| collagen type I fibers, proteoglycans, and glycoproteins (these play a role in binding calcium) |
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|
Term
| what is typically found in the inorganic region of bone matrix? |
|
Definition
| calcium and phosporus in the form of hydroxyapatite crystals |
|
|
Term
| what enzyme does the osteoclast use to help lower the pH of the microenvironment? |
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Definition
|
|
Term
| what is it clinically termed when the mineralization of the bone matrix is impaired (soft bones) due to vitamin D deficiency? |
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Definition
|
|
Term
| in children, what is growing bone vitamin D deficiency termed? |
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Definition
|
|
Term
| what is osteogenesis imperfecta (Brittle Bone disease)? |
|
Definition
| genetic disorder of type I collagen characterized by repeated fractures after minor trauma |
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Term
|
Definition
| decreased bone mass; rate of minerals to organic matrix is normal; bone is characterized by spicules that are thinner than normal bone |
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|
Term
| what are the two ways in which bones can develop? |
|
Definition
| intramembranous ossification and endochondral ossification |
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|
Term
| what is typical of intramembranous ossification? |
|
Definition
| numerous osteoblasts on surface of newly deposited bone, bone spicules interconnect forming trabeculae, no previous cartilage model, and the early periosteum is forming from cellular connective tissue |
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|
Term
| how does intramembranous ossification begin? |
|
Definition
| by condensation of mesenchymal cells |
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Term
| the site of osteoblast formation in intramembranous ossification is termed? |
|
Definition
| primary ossification center |
|
|
Term
| what are the 2 phases of endochondral ossification? |
|
Definition
| hypertrophy and degeneration of chondrocytes, and osteogenic bud of osteoprogenitor cells and blood vessels penetrate the space left by the dead chondrocytes |
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|
Term
| if a bone collar is present, what type of ossification is indicated? |
|
Definition
| endochondral ossification |
|
|
Term
| where does the secondary ossification center arise later in endochondral ossification? |
|
Definition
|
|
Term
| describe the sequence of events in endochondral ossification |
|
Definition
| bone collar forms, cartilage hypertrophy, osteogenic bud of blood vessels, osteoblasts differentiate, and primary ossification center expands |
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|
Term
| what are the 5 zones of the epiphyseal plate? |
|
Definition
| zones of reserve, proliferation, hypertrophy, calcification, resorption |
|
|
Term
| bone formation is take place at what surface(s) of the epiphyseal plate? |
|
Definition
| the epiphyseal and diaphyseal surface |
|
|
Term
| describe the cutting cone in the bone remodeling unit |
|
Definition
| advances and resorbs bone |
|
|
Term
| what does the closing cone in the bone remodeling unit do? |
|
Definition
|
|
Term
| what is the purpose of bone remodeling? |
|
Definition
| maintains shape of bone during growth |
|
|
Term
| the deficiency of growth hormone during the developing years that leads to failure of bone growth is termed what? |
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Definition
|
|
Term
| excess growth hormone during the developing years that leads to an abnormal increase in the length of bones is termed what? |
|
Definition
|
|
Term
| excess growth hormone in adulthood that leads to thickening of the bones since the growth plates have already closed is termed what? |
|
Definition
|
|
Term
| what are the seven steps in fracture repair? |
|
Definition
| blood cot forms, periosteum and endosteum proliferate, hyaline cartilage forms, primary bone forms, bone callus unites fracture temporarily, osteoblasts form and deposit new bone, remodeling occurs |
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Term
|
Definition
|
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Term
|
Definition
| mesenchymal stem cells, can give rise to osteoblasts |
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Term
|
Definition
|
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Term
|
Definition
| bone lining cells on external bone |
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Term
|
Definition
| bone lining cells on internal bone |
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Term
|
Definition
|
|
Term
|
Definition
| Calcium binding protein, vit K dependent, in ECM |
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Term
|
Definition
| arise from periosteal vessels |
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Term
|
Definition
| lines internal surface with osteoprogenital cells |
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