時差N小時:癢癢 Why scratching is so effective

When you have an itch, you scratch it.

癢癢就撓撓。

What could be more simple than that?

還有什么比這更簡單的嗎?

Scratching itches is one of our most basic instincts,one which we share with many other animals.

撓癢是我們與許多其他動物共同具有的最基本的本能之一。

Have you ever stopped to wonder, mid-scratch,exactly why scratching is so effective againstitching?

但你是否在撓舒服的同時停下來想過,為什么抓撓能治癢?

We'll learn the itchy truth, on today's Moment of Science.

我們將在今天的《科學一刻》節(jié)目中了解有關發(fā)癢的事實,。

On the most basic level, scratching is away to remove whatever irritant might be causing the itch in the first place.

從最基本的角度上看, 抓撓首先是一種去除任何可能會導致瘙癢刺激的方式。

If an insect is biting you, or you have a patch of dead, flaking skin, scratching has a goodchance of getting rid of it.

如果一只昆蟲咬了你,或者你有一塊死皮,皮膚剝落,抓撓很有可能將它弄掉。

In this case, it's pretty obvious why the scratching works.

這樣的情況很明顯說明了為什么抓撓會有效。

Much of the time we scratch, however, it seems to be somewhat after the fact.

大部分時間我們總是在真正癢了之后才會去抓撓。

Perhaps the mosquito has already bitten us and flown away, and we are left scratching at theswelling bite.

也許蚊子已經(jīng)吸完血飛走了我們才會抓撓被叮咬的腫脹部分。

Clearly this won't get rid of the mosquito.

很明顯,這不會擺脫蚊子。

Is there any good reason for this kind of scratching, or is this just an over-zealous instinctthat doesn't realize it's too late?

但這種抓撓有什么好的理由,或者只是一種不知道太晚的過度本能嗎?

Actually, this kind of scratching can serve two additional functions.

實際上,這樣的抓撓可以起到兩個額外的作用。

First, it can stimulate the irritated tissues and cause extra blood to flow to them.

首先可以刺激激擴張組織,使額外的血液流動。

This can help your immune system remove whatever itchy substances might be below yourskin.

這可以幫助你的免疫系統(tǒng)清理在你皮膚下任何可能發(fā)癢的物質(zhì)。

Second, it can trick your brain into ignoring the annoying itch.

其次是可能會欺騙你的大腦忽略這惱人的癢癢。

Your nervous system can generally process only one stimulus from a given area of your skin at atime.

你的神經(jīng)系統(tǒng)通常只能處理一次皮膚特定區(qū)域的刺激。

If you scratch at an area that itches, this new, greater stimulus can override the itching,effectively blocking it out.

如果你抓撓很癢的部位,這種新的、更大的刺激可以覆蓋瘙癢,有效地阻止它。