Why I Sneeze, Shiver, Hiccup, and Yawn

Why I Sneeze, Shiver, Hiccup, and Yawn

为什么会打喷嚏、发抖、打嗝、打呵欠

You are playing hide-and-seek. You've found a good hiding place. You want to be as quiet as you can. All of a sudden- KA-CHOO! You sneeze. Everyone knows where you are. Why do you sneeze-even when you don't want to? You are eating lunch with your friends. You are in the middle of telling them a story. All at once you hiccup. HIC! Your friends start to laugh. HIC! You try to stop. HIC! But you can't. HIC! Why do you hiccup even when you don't want to?

你们正在腕捉迷藏。你找到了一个最棒的地方,正想悄悄地躲起来,突然之间--阿嚏! 你打了一个大喷嚏。所有人都知道你在哪里了。 为什么你会打喷嚏?即使在你不想打的时候。 吃午餐的时候,朋友们正在津津有味地听你讲故事。忽然,你开始打喝,喝!他们哈哈大笑，嗝!你想停下来，!可怎么也做不到，嗝! 为什么你会打喝?即使在你不想打的时候。

A sneeze is a reflex. So is a hiccup. You don't have to think about making reflexes happen. They happen whether you want them to or not. They happen very fast, and it is hard to stop them. Shivering and yawning are also reflexes. All reflexes work through your nervous system.

打喷嚏是一种反射动作,打嗝也是。你想都不用想,反射动作就自然发生了。不管你要不要,反射动作来得很快,而且很难阻止。发抖、打呵欠也是反射动作。所有的反射动作都是神经系统控制的。

Your nervous system is made up of two parts. One part is the nerves. The nerves look like long, thin threads. They reach all over your body. The other part is the spinal cord and brain. The spinal cord is a thick bundle of nerves. It is inside your spine, or backbone. The brain is at the upper end of the spinal cord. It is made up of billions of tiny nerves. Nerves are like telephone wires. They carry messages back and forth. The brain and spinal cord are like the main office of the telephone company. All the messages must go through here.

神经系统由两部分组成，其中一部分是外周神经。外周神经开起来像又长又细的线，遍布身体的每一个地方。 另一部分是脊髓和大脑。脊髓是一束粗粗的神经,在脊椎里面。大脑在脊髓的顶端,里面有数不清的细小的神经。 外周神经就像电话线,将信息传来传去。大脑和脊髓则像电话线路中枢,所有的信息都必须经过这个地方。

Suppose you put your finger on a hot stove. The nerves in your hand sense that the stove is hot. They send out a message. The message speeds along nerves from your hand to your spinal cord. Here the message passes to a different nerve. This nerve controls the muscles that move your arm. A signal flashes through the nerve. It tells your muscles to move your hand and fast. Before you even know what hurts, your hand jerks away from the stove.

如果你的手碰到热锅,手上的神经会感觉到锅很烫,立刻发出一个信息。这个信息迅速沿着神经从手传到脊髓,然后又传给另一个不同的神经。这个神经会控制肌肉 移开你的手。 信息快速通过神经,它告诉你的肌肉把手移开--赶快!甚至在你意识到会被烫伤之前，手已经缩回来了。

Pulling your hand off a hot stove is a reflex. It happens very quickly, and it is not completely under your control. It happens automatically, without your having to think about making it happen.

让手快速离开热锅,就是一种反射动作。反射的速度很快,而且几乎不由你控制,一受到刺激就会自动发生了，你想都不必想，手自然就离开了热锅。