医学英语综合教程课文和翻译 .docx

Unit2. CellsandAging

Agingisanormalprocessaccompaniedbyaprogressivealterationofthebody’shomeostaticadaptiveresponses;thespecializedbranchofmedicinethatdealswiththemedicalproblemsandcareofelderlypersoniscalledgeriatrics.

衰老是一种正常的生理过程，伴有机体内环境稳定适应性应答的进行性改变。研究老年人的健康问题和保健的一门特殊医学分支被称作老年病学

Theobviouscharacteristicsofagingarewellknown;grayingandlossofhair,lossofteeth,wrinklingofskin,decreasedmusclemass,andincreasedfatdeposits.Thephysiologicalsignsofagingaregradualdeteriorationinfunctionandcapacitytomaintainaconstantinternalenvironment(homeostasis)inresponsetochangesintemperature,diet,andoxygensupply.Thesesingsofagingarerelatedtoanetdecreaseinthenumberofcellsinthebodyandtothedysfunctioningofthecellsthatremain.

衰老的明显特征众所周知：头发花白和脱落，牙齿脱落，皮肤起皱，肌肉减少，脂肪积存增加。衰老的生理征兆是机体对环境刺激反应的功能和能力的逐渐退化如同维持机体内环境稳定来应对温度，饮食和氧气供应改变的能力减退一样，机体新

陈代谢也减慢了。衰老的这些迹象与机体中细胞数目的净减少以及存余细胞的功能紊乱有关。

Theextracellularcomponentsoftissuesalsochangewithage.

Collagenfibers,responsibleforthestrengthintendons,increaseinnumberandchangeinqualitywithaging.Thesechangesinthecollagenofarterialwallsareasmuchresponsiblefortheirlossofextensibilityasarethedepositsassociatedwithatherosclerosis,thedepositionoffattymaterialsinthearterialwalls. Elastin,anotherextracellularcomponent,isresponsiblefortheelasticityofbloodvesselsandskin.Itthickens,fragments,andacquiresagreateraffinityforcalciumwithage–changesthatmayalsobeassociatedwiththedevelopmentofatherosclerosis.

组织的细胞外成分也随着年龄的变化而变化。负责肌腱力量的胶原纤维的数量增加，而质量却随着衰老降低。动脉壁上的胶原质的变化与动脉壁伸展性丧失有关，正如动脉粥样硬化，即动脉壁脂肪物质堆积造成动脉壁伸展性缺失一样。弹性蛋白是另一种细胞外成分，与血管和皮肤的弹性有关，随着年龄的变化，它变粗，易断裂并且与钙有很大的亲和力，这些变化可能也与动脉粥样硬化的发生有关。

Glucose,

themostabundantsugarinthebody,mayalso

playarole

intheaging

process.Accordingtoonehypothesis,glucose

isadded,

haphazardly,

toproteinsinsideandoutsidecells,fo