英语六级听力在线听mp3材料

【#文档大全网# 导语】以下是®文档大全网的小编为您整理的《英语六级听力在线听mp3材料》，欢迎阅读！



英语六级听力在线听mp3材料

Ow! Why Hot Feels Cold

Kids don’t try this at home!

Have you ever dipped your toe into a very hot bath and felt a flash of icy cold just before you realize that its really burning? After you pull your toe out, you might wonder what causes very hot water to feel cold.

This odd sensation is called paradoxical cold and is caused by the temperature receptors in the skin. There are separate, specific receptors that respond to decreases or

increases in skin temperature. If skin temperature drops, the cold receptors fire and if it increases, the warmth receptors fire.

However, if a strong stimulus, like very hot water, can stimulate not only the warmth receptors but also stimulate the pain receptors. These warn us that we are doing ourselves damage, and should take action to prevent it. The strong stimulus can also cause the abnormal stimulation of the cold receptors.

Over-stimulation can cause the confusing sensation of cold, hot and pain, but as long as we’re clear about pulling the toe out to safety, paradoxical cold is just another strange trick of the senses.

噢！为什么明明是热的却让人感到冰冷呢？ 小孩子不要在家尝试以下实验！






你是否尝试过把脚趾伸进很烫的浴盆里却感到瞬间的冰冷，回过神来才意识到水是滚烫的？也许抽出脚趾之后你很想知道，是什么原因让人觉得这滚烫的热水很冷。

这种怪异的感受称为诡冷觉，其实是皮肤内的温度感受器在作祟。皮肤内分布着独立的专门感受器，能对皮肤温度的升降作出反应。如果皮肤温度下降了，冷感受器就发出警告，如果皮肤温度上升了，暖感受器则发出警告。

不过，如果遇到很强烈的外部刺激，比如很烫的水，不但能激发暖感受器，而且会激发痛感受器。这些反应提醒我们，我们正在伤害自己，应该马上采取措施制止伤害的继续。这种强烈的刺激也会导致冷感受器被异常激发。

过度刺激会使人体对冷、暖和痛觉的感受发生错乱，但只要我们清醒地意识到应该把脚趾挪到安全的地方，诡冷觉也仅仅一种奇怪的感官游戏而已。

本文来源：https://www.wddqxz.cn/9c356bd02c3f5727a5e9856a561252d380eb20ce.html