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In the face of cold weather, our body may reduce blood flow at the skin and the body’s extremities. VCG

 

 

Cold air has hit China as we enter deep winter. Going outdoors, you may feel the cold wind trying to penetrate your coat, hitting body parts covered by little material – such as the face. To explore how our bodies respond to coldness, let’s first explore how we feel “cold”.

步入深冬，寒潮席卷全國。戶外出行，你可能會(huì)感到冷風(fēng)已穿透外套，臉頰等衣料遮掩較少的身體部位備受侵襲。為了探究我們的身體如何對寒冷做出反應(yīng)，首先要搞清楚我們是如何感覺“冷”的。

 

Human skin is filled with temperature-sensing nerve receptors named TRP, and they receive stimuli from the environment. Such stimuli may be pressure, cold, heat, or chemical, etc. To sense cold, the brain uses a kind of receptor called TRPM8.

人類的皮膚粘膜表面遍布一種名為TRP的溫度感知神經(jīng)感受器，會(huì)對環(huán)境里的刺激信號產(chǎn)生反應(yīng)。這些刺激信號可能包括壓力、冷熱以及化學(xué)刺激等。而大腦為感知寒冷，使用了一種名為TRPM8的低溫感受器。

 

Scientists first studied TRPM8 in 2002, discovering that its stimuli include a temperature between 10 C and 30 C and menthol. This is also why mint-flavored toothpaste can make our mouths cooler and fresher. When the TRPM8 is hit by stimuli, it sends an electric signal to the brain which understands the signal as “cold”.

研究人員在2002年首次研究出TRPM8，并發(fā)現(xiàn)10℃至30℃的低溫（相比正常體溫）和薄荷醇均是其活化信號。也正是因此，我們會(huì)覺得薄荷味的牙膏讓口腔變得更冰爽、清新。TRPM8受到刺激時(shí)，會(huì)向大腦發(fā)送電信號，而大腦將這個(gè)信號理解為“冷”。

 

The body then protects itself from the cold through different means. According to Live Science, the body slows down its muscles and the nervous system. In this way, it reduces heat loss.

隨后身體會(huì)通過不同的方式，保護(hù)自身免受寒冷。據(jù)美國生命科學(xué)網(wǎng)報(bào)道，在感到低溫后，身體會(huì)減緩肌肉和神經(jīng)系統(tǒng)的活動(dòng)，從而減少熱量損失。

 

The cold also leads to less blood flow. The body will first reduce blood flow at the skin and the body’s extremities, including the fingers, hands and feet. This is why these parts tend to feel cold first.

寒冷還會(huì)導(dǎo)致血液流動(dòng)減少。身體首先會(huì)減少皮膚和四肢(包括手指、手和腳)的血液流動(dòng)，因此這些部位會(huì)先感覺到冷。

 

“We try to limit how much blood we send out there, so it limits how much heat we put into the environment,” John Castellani at the US Army Research Institute of Environmental Science told Live Science.

美國陸軍環(huán)境醫(yī)學(xué)研究所的約翰·卡斯特拉尼在接受美國生命科學(xué)網(wǎng)采訪時(shí)表示:“身體試圖限制向外輸送血液，以此減少向環(huán)境中釋放熱量。”

 

To bring the body’s temperature back up, the body tends to produce heat itself by allowing muscles and organs to shake, more commonly known as shivering. Although this attempt may not be effective, it is more like a warning to people about the cold. In extreme cases, the body may be unable to maintain its core temperature inside, leading to injuries such as frostbite.

為了恢復(fù)體溫，身體往往通過肌肉和器官的抖動(dòng)來產(chǎn)生熱量，這就是我們通常說的“寒戰(zhàn)”。打冷戰(zhàn)雖然可能沒法產(chǎn)生多少熱量，但更像是對人們的一種警告。在極端情況下，身體可能無法保持內(nèi)部核心溫度，就會(huì)導(dǎo)致凍傷等傷害。

 

以上文章內(nèi)容選自《21世紀(jì)學(xué)生英文報(bào)》高一893期