首页
登录
职称英语
The polar vortex (极地旋风) currently sweeping across the North American contine
The polar vortex (极地旋风) currently sweeping across the North American contine
游客
2023-08-04
77
管理
问题
The polar vortex (极地旋风) currently sweeping across the North American continent is bringing with the scenes usually associated with the Arctic or Antarctic. Massive snowfall and violent winds have brought temperatures down to record lows. In some areas of the US, such as the state of Indiana, all but essential emergency vehicles are banned from the roads. People are being urged to remain inside in the warm.
The human body is not designed for polar cold—most of us live in temperate and tropical climate, where the mercury rarely dips below freezing. There are populations that have adapted to polar extremes—like the Inuit in Arctic Canada and tribes like the Nenets in the north of Russia—but the vast majority of Homo sapiens (现代入) has no experience of living in such sub-zero temperatures. And while our ingenuity and expertise has allowed us to create clothing to withstand all but the most violent Arctic blizzards, polar survival is all about keeping out of the most fearsome cold unless you absolutely have to.
What happens when we get cold? The human body has several defence mechanisms to try and boost our core temperature when it gets chilly. Our muscles shiver and teeth chatter. Our hairs rise and our flesh forms
"goosebumps"
—a kind of evolutionary echo from the times when our ancestors were covered in fur. The hypothalamus (下丘脑) , the gland in the brain that acts as your body’s thermostat (恒温器) , stimulates these reactions to keep the body’s vital organs warm, at least until it can find some kind of warmth and shelter.
The hypothalamus’s mission is to keep the core warm at all costs—sacrificing the extremities if need be. That’s why we feel pins and needles in our fingers and toes in extreme cold—the body is keeping its warm blood close to the centre, constricting blood supply in the outer regions such as the end of our limbs. In extreme cold, and especially if bare skin is open to the elements, this effect can end in frostbite.
So how do other warm-blooded animals living in such climate cope when we can’t? Polar animals are either covered in winter coats of fur—which traps warm air close to the body—or else large quantities of fat, sometimes inches thick. Fat does not transfer heat very well, so it keeps it inside the body. Humans, with naked skin and relatively little fat, just aren’t built for these environments.
But we have learned to imitate these qualities. Scientists in Antarctic stations, for instance, dress in layers upon layers, which traps warm air close to the body like fur does. [br] How does human body keep the core warm in extreme cold according to the passage?
选项
A、Constrict blood supply to the centre.
B、Reduce blood flow in the outer regions.
C、Keep its warm blood close to the skin.
D、Speed up the body’s blood flow.
答案
B
解析
细节题。根据题干中的keep the core warm可定位到第四段。该段第一、二句提到下丘脑的任务是不惜一切代价保持人体核心温度,因此在极寒天气中,人们会感到手脚发麻,这时,人体让温暖的血液保持在人体核心器官附近,限制人体外围的血液流动,因此B项表述符合原文,故选B。
转载请注明原文地址:https://tihaiku.com/zcyy/2896743.html
相关试题推荐
[originaltext][9]TheAmericanpatentsystem,providedforintheConstitut
[originaltext][9]TheAmericanpatentsystem,providedforintheConstitut
[originaltext]NotenoughAmericanstudentswanttobeengineers,mathematic
[originaltext]NotenoughAmericanstudentswanttobeengineers,mathematic
[originaltext][9]Atfirst,mostAmericansdidn’tthinktherewasanything
[originaltext][9]Atfirst,mostAmericansdidn’tthinktherewasanything
[originaltext][9]Americanswhoremember"thegoodolddays"arenotalone
[originaltext]AmericanvisitorstoEastAsiaareoftensurprisedandpuzzle
[originaltext]AmericanvisitorstoEastAsiaareoftensurprisedandpuzzle
[originaltext]ThereissayinginAmericaneducationalcirclesthatHarvard
随机试题
【B1】[br]【B6】A、onB、inC、toD、withCbecommunicatedto的用法。故选C。
[originaltext]W:Michael,whereareyouheading?Youseemtobeinahurry.M:
A公司为非上市公司,按年对外提供财务报告,有关股票投资业务如下(所得税税率为25
近年革兰阳性球菌败血症最常见的致病菌是A.金黄色葡萄球菌 B.表皮葡萄球菌
(2014年) ABC会计师事务所审计甲公司2013年财务报表,审计项
低合金高强度结构钢质量等级分为()级。A、3 B、4 C、5 D、6
初步设计阶段投资控制的目标应不超过( )。 A、投资估算 B、设计总概算
表面活性剂可用作()A.稀释剂 B.增溶剂 C.乳化剂 D.润湿剂 E
远东股份有限公司(以下简称远东公司)为增值税一般纳税人,2×21年1月,远东公司
清水池是给水系统中调节水厂均匀供水和满足用户不均匀用水的()构筑物。A、沉淀
最新回复
(
0
)