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,单击此处编辑母版标题样式,单击此处编辑母版文本样式,第二级,第三级,第四级,第五级,.,*,单击此处编辑母版标题样式,单击此处编辑母版文本样式,第二级,第三级,第四级,第五级,.,*,单击此处编辑母版标题样式,单击此处编辑母版文本样式,第二级,第三级,第四级,第五级,.,*,单击此处编辑母版标题样式,单击此处编辑母版文本样式,第二级,第三级,第四级,第五级,.,*,单击此处编辑母版标题样式,单击此处编辑母版文本样式,第二级,第三级,第四级,第五级,.,*,单击此处编辑母版标题样式,单击此处编辑母版文本样式,第二级,第三级,第四级,第五级,.,*,单击此处编辑母版标题样式,单击此处编辑母版文本样式,第二级,第三级,第四级,第五级,.,*,单击此处编辑母版标题样式,单击此处编辑母版文本样式,第二级,第三级,第四级,第五级,.,*,Bob Zheng,Wuhan University,1,.,Bob Zheng1.,Bone replacement is the replacement of old bone tissue by new bone tissue,Never,metabolically,at rest,Replacing itself throughout adult life,2,.,Bone replacement is the replac,Remodeling allows worn or injured bone to be removed and replaced with new tissue,3,.,Remodeling allows worn or inju,Remodeling allows bone to serve as the bodys storage area for calcium,Constant supply of Ca2+ in the blood stream needed for,:,Transmission of nerve impulses,Muscle contraction,Blood coagulation,Cell division,4,.,Remodeling allows bone to serv,Osteoclast and osteoblast,5,.,Osteoclast and osteoblast5.,Sufficient quantities of calcium(Ca) and phosphorus(P),6,.,Sufficient quantities of calci,Sufficient amounts of vitamins, particularly vitamin D,7,.,Sufficient amounts of vitamins,Proper amounts of the hormones,Growth hormone(GH), Calcitonin(CT), Parathormone(PTH), Sex hormones,8,.,Proper amounts of the hormones,Secreted by the pituitary gland , responsible for general growth of bones,Too much Gigantism,Too little Dwarfism,9,.,Secreted by the pituitary glan,CT is produced by the thyroid gland,inhibits,osteoclastic activity,PTH is secreted by the parathyroid glands,increases,the number and activity of osteoclasts,Antagonistic,CT PTH,10,.,CT is produced by the thyroid,Control of Bone Deposition,Control of Bone Resorption,Ca,2+, controlled by negative feedback loop,11,.,Control of Bone DepositionCont,Promote the growth of new bone,Bring about the degeneration of cartilage cells,12,.,Promote the growth of new bone,Aging for skeletal syetem happens when Osteoblast activity declines, while osteoclast activity remains level,Loss of calcium from bones,13,.,13.,For female, this loss begins after age 40 but for male , this loss typically does not begin until after 60,14,.,For female, this loss begins a,MENOPAUSE!,Remember, estrogen(sex hormone for female) stimulates osteoblast activity and synthesis of bone matrix,Men continue to produce androgens (sex hormone for male) into late life and thus are not as affected.,15,.,MENOPAUSE! Men continue to pr,Another effect for aging is the decrease in the rate of protein formation,Less organic matrix more inorganic matrix,Bones become brittle and easy to fracture,16,.,Another effect for aging is th,When the loss of bone mass compromises normal function a person is diagnosed with osteoporosis.,17,.,When the loss of bone mass com,Premature menopause,Body build short women have less bone mass to begin with,Weight thinner at greater risk,Smoking decreases estrogen levels,Lack of dietary calcium,Sedentary lifestyle decrease rate of absorption,Drugs alcohol, cortisone, tetracycline,Nulliparity (never had children),Ancestry or Family history,18,.,Premature menopause 18.,No smoking,Take in more calcium,Dont sit all the day,Be careful when taking drugs,19,.,No smoking19.,20,.,20.,
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