医学专业英语汇报PPT.ppt

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1、BobZhengWuhanUniversityBonereplacementisthereplacementofoldbonetissuebynewbonetissueNevermetabolicallyatrestReplacingitselfthroughoutadultlifeRemodelingallowswornorinjuredbonetoberemovedandreplacedwithnewtissueRemodelingallowsbonetoserveasthebody’sstorageareaforc

2、alciumConstantsupplyofCa2+inthebloodstreamneededfor:TransmissionofnerveimpulsesMusclecontractionBloodcoagulationCelldivisionOsteoclastandosteoblastSufficientquantitiesofcalcium(Ca)andphosphorus(P)Sufficientamountsofvitamins,particularlyvitaminDProperamountsoftheh

3、ormonesGrowthhormone(GH),Calcitonin(CT),Parathormone(PTH),SexhormonesSecretedbythepituitarygland,responsibleforgeneralgrowthofbonesToomuchGigantismToolittleDwarfismCTisproducedbythethyroidgland,inhibitsosteoclasticactivityPTHissecretedbytheparathyroidglands,incre

4、asesthenumberandactivityofosteoclastsAntagonisticCTPTHControlofBoneDepositionControlofBoneResorption[Ca2+]controlledbynegativefeedbackloopPromotethegrowthofnewboneBringaboutthedegenerationofcartilagecellsAgingforskeletalsyetemhappenswhenOsteoblastactivitydeclines

5、,whileosteoclastactivityremainslevelLossofcalciumfrombonesForfemale,thislossbeginsafterage40butformale,thislosstypicallydoesnotbeginuntilafter60MENOPAUSE!Remember,estrogen(sexhormoneforfemale)stimulatesosteoblastactivityandsynthesisofbonematrixMencontinuetoproduc

6、eandrogens(sexhormoneformale)intolatelifeandthusarenotasaffected.AnothereffectforagingisthedecreaseintherateofproteinformationLessorganicmatrixmoreinorganicmatrixBonesbecomebrittleandeasytofractureWhenthelossofbonemasscompromisesnormalfunctionapersonisdiagnosedwi

7、thosteoporosis.PrematuremenopauseBodybuild–shortwomenhavelessbonemasstobeginwithWeight–thinneratgreaterriskSmoking–decreasesestrogenlevelsLackofdietarycalciumSedentarylifestyle–decreaserateofabsorptionDrugs–alcohol,cortisone,tetracyclineNulliparity(neverhadchildr

8、en)AncestryorFamilyhistoryNosmokingTakeinmorecalciumDon’tsitallthedayBecarefulwhentakingdrugs