首页
外语
计算机
考研
公务员
职业资格
财经
工程
司法
医学
专升本
自考
实用职业技能
登录
外语
Researchers have known for years that animals have a "clock" somewhere in their brains a control-centre that regulates circadian
Researchers have known for years that animals have a "clock" somewhere in their brains a control-centre that regulates circadian
admin
2009-06-15
105
问题
Researchers have known for years that animals have a "clock" somewhere in their brains a control-centre that regulates circadian(生物节奏的) rhythms. Circadian rhythms are the body’s daily biological cycles, controlling such activities as sleep and wakefulness. In November 1988, neuroscientists at the University of Virginia in Charlotteville reported that the supra chasmatic nucleus(SCN), a small cluster(束)of cells in the middle of the brain that neuroscientists have long suspected of playing a role in daily rhythms, is the long-sought biological clock.
The investigators performed a series of tissue-transplant experiments with hamsters (仓鼠). Some of the animals were normal hamsters, which have a circadian cycle of 24 hours; the others were mutant(变异型)hamsters whose cycles were only 20 or 22 hours long.
The scientists first removed the SCN from the brans of the hamsters in both groups. They then implanted an SCN from a mutant hamster into the brain of each normal animal, and vice versa. When the hamsters had recovered from their operations, the circadian rhythms of the two groups were reversed. The normal hamsters had a daily cycle of 20 to 22 hours, and the mutants were on a 24-hour cycle.
The identification of the internal clock is an important stepping-stone in understanding the basic, automatic mechanisms of brain function. It may also help in finding ways to relieve human sleep disorders.
选项
A、Right
B、Wrong
C、Not mentioned
答案
B
解析
实验的目的是要确定SCN的位置。
转载请注明原文地址:https://kaotiyun.com/show/z91d777K
本试题收录于:
职称英语卫生类C级题库职称英语分类
0
职称英语卫生类C级
职称英语
相关试题推荐
Usingtheinformationinthetext,completeeachsentence14-18withanexpressionfromthelistbelow.Foreachsentence(14
Readthefollowingpassageanddecidewhichanswerbestfitseachspace.Forquestions26~45,markoneletterA,B,CorDo
Amulticulturalpersonissomeonewhoisdeeplyconvincedthatallculturesareequallygood.【R1】______Andmostlikelyhehasbe
Amulticulturalpersonissomeonewhoisdeeplyconvincedthatallculturesareequallygood.【R1】______Andmostlikelyhehasbe
1.Thefilmisnotwithoutitsdrawbacks.Disappointment,failure,selfdoubt,regretsoveropportunities,missedormisusedthe
TheplaceisalovelymeadowsurroundedbydeepwoodsonahilltopoverlookingabeautifullakeintheCatskillMountains120mi
1.Moreandmore,theoperationsofourbusinesses,governments,andfinancialinstitutionsarecontrolledbyinformationthate
FRIENDSHIP0Ibelievethatnothingmattersasmuchashavingacoupleofreallygood00friends.Theyhelpyoufeell
A.ThepriceofFrostyPaws.B.Noharmtohuman.C.Thecreationofanewkindoficecreamfordogs.D.Harmtohuman.E.Feed
ThestandardssetfouryearsagoinSeoulwillbefarbelowtheathletes’capabilitiesnow.
随机试题
设A为三阶矩阵,A的特征值为λ1=λ2=1,λ3=3,对应的线性无关的特征向量为α1,α2,α3,令P1=(α1+α3,α2-α3,α3),则P1-1AP1().
改正下列句子中虚词方面的错误,并说明理由。
A.腹腔动脉B.髂外动脉C.髂内动脉D.肠系膜前动脉E.荐中动脉阴部内动脉是()的延续干
女,50岁,因患短肠综合征予全胃肠外营养(TPN)治疗。应用1周时患者出现昏迷,但尿内无酮体。患者既往曾有空腹血糖高(11mmol/L)。此患者的诊断是
下列资金成本中,属于资金占用费的有()。
开户单位之间的经济往来,除按规定的范围可以使用现金外,应当通过()进行转账结算。
下列关于纯货币理论观点的表述不正确的是()。
目前日本的物流成本管理多处于第三个层次上,对企业物流部门的成本管理同步于销售和生产部门。而在我国,对物流成本的管理还更多的停留在第一个层次上。()
2013年12月10日至13日,中央经济工作会议在北京举行,会议分析了国内外经济形势,对2013年经济工作进行了总结,提出了2014年经济工作的总体要求和主要任务。为贯彻落实中央经济工作会议精神,某市专门召开会议研究部署2014年经济工作,会议根
A、Thelocalpeoplesellthebricksforaliving.B、Thelocalpeopleareshortofcultureknowledge.C、Thelocalpeopleneedbric
最新回复
(
0
)