英語聽力文摘562 寒冷的曬傷！
- 聽力原文
- 參考譯文
A listener from Ontario, California wrote to A Moment of Science with a question her sons had asked her.
The boys wondered why is it that when you get sunburned you often feel chilled. It really does seem like a contradiction: you’ve been burned, but you feel cold.
The answer to this seeming contradiction is in your blood.
Sunburn is an injury to your skin, and your body’s usual reaction to being injured is to enlarge the blood vessels in the damaged area. This allows more blood to be circulated near the injury, where it can deliver cells to help heal the wound.
Since sunburn is usually damage to the surface of your skin, the blood vessels in the area of the burned skin enlarge so that more blood is circulated there; this is where the redness comes from.
When you’re sunburned a large area of your body is usually involved, so a result of so much blood being near the surface of your skin is that you lose more than a normal amount of body heat through it.
Your brain tries to balance this loss of heat by activating reactions which attempt to conserve heat. A common reaction is shivering, which is the body trying to generate heat in an effort to compensate for the heat that is being lost.
So, even when your skin feels hot to the touch, you shiver and feel chilled as your body tries to make up for the extra heat loss.
寒冷的曬傷!
一名來自加利福尼亞安大略的聽眾給我們寫信，讓我們解答她兒子們問她的問題。
這些小男孩想知道為什么人曬傷的時(shí)候會(huì)覺得冷。這簡直就是自相矛盾嘛。你明明曬傷了，卻覺得冷。
這個(gè)看上去自相矛盾的問題的答案就在你的血液當(dāng)中。
曬傷表明你的皮膚受到了損傷，而通常人體應(yīng)對(duì)損傷的辦法就是使受創(chuàng)位的血管擴(kuò)張。這使得更多的血液在傷口附近循環(huán)，同時(shí)血液中的一些細(xì)胞也會(huì)被輸送到傷口附近，幫助傷口愈合。
由于曬傷通常會(huì)損害你的皮膚表面，而曬傷部位的血管會(huì)擴(kuò)張，使更多的血液在附近循環(huán)。這就是為什么曬傷部位會(huì)變紅。
曬傷通常會(huì)波及到人體的大部分區(qū)域。而大量血液聚集在皮膚表面附近的結(jié)果就是：你會(huì)散失比平時(shí)更多的熱量。
為了平衡損失，大腦嘗試通過刺激人體作出某種反應(yīng)來保存熱量。該反應(yīng)通常表現(xiàn)為顫抖，顫抖表明人體正試圖產(chǎn)生熱量來補(bǔ)充正在散失的那一部分。
因此，即使你的皮膚摸一下都覺得發(fā)燙，但你還是會(huì)顫抖，覺得冷，因?yàn)檫@時(shí)人體正設(shè)法補(bǔ)充額外散失的熱量。
