How Does Nervous System Work?
神经系统怎样运作？ I-06 / 006

Have you ever shivered on a cold day? You may not have noticed, but as you shivered, you body warmed up. Shivering is one way your body stays warm. It happens when signals are sent from the nervous system to the muscles. This is how it works.

The nervous system has two parts. One part is the nerves. They look like long and thin threads. Their job is to carry messages to all parts of the body. The spinal cord and the brain make up the other part of the nervous system. The spinal cord is a large bundle of nerves inside the backbone. Signals from the brain travel down the spinal cord. They go to the rest of the body through the nerves. Muscles receive these signals.

Imagine waiting for a bus on a street corner. It's a cold day, the bus is late, and you feel chilled. Here's what happens.

A control center in your brain senses that you're cold. It sends a message down the spinal cord to all the nerves. The message races through nerves that connect to other nerves. Then it goes from the nerves to the muscles. The message says, “Warning! Prepare for action! ”

When a muscle moves, it makes heat. That is why you get warm when you run or play soccer. When your muscles get the signal that you are cold, they get busy. First they become tight, then they loosen. They tighten then loosen over and over again. This makes you shiver. You also get warmer.

Words and Phrases

shiver [ˈʃɪvə] 动（因寒冷、害怕等）颤抖，哆嗦

warm up 变热

nervous system 神经系统

muscle [ˈmʌsl] 名 肌肉；肌肉组织

nerve [nɜ:v] 名 神经

spinal [ˈspaɪnl] 形 脊柱的；脊髓的

cord [kɔ:d] 名（细）绳，绳索

spinal cord 脊髓

backbone [ˈbækbəʊn] 名 脊椎，脊柱

control center 控制中心，调度室

race through 快速穿过

Practice

1. Shivering helps your body________.

A. keep calm

B. stay warm

C. cool down

D. stand up straight

2. The nervous system has_________.

A. one part

B. three parts

C. two parts

D. many parts

3. The spinal cord is a large bundle of_________.

A. muscles

B. brain cells

C. nerves

D. signals

4. Nerves tell the muscles to_________.

A. stop

B. relax

C. get ready

D. cool down

5. When you shiver, you get________.

A. weaker

B. colder

C. stronger

D. warmer

译文

神经系统怎样运作？

你曾在寒冷的天气里发抖吗？你可能没有注意过，但当你发抖时，身体就会变暖和。发抖是你身体保持温暖的一种方式。当神经系统向身体肌肉组织发出信号时，这种现象就会发生。神经系统就是这样运作的。

神经系统有两部分，一部分是神经，神经看起来像细长的丝线，它们负责向身体各部分传递信息。脊髓和大脑组成神经系统的另一个部分。脊髓是脊椎内部的一大束神经。来自大脑的信号传送到脊髓，再通过神经传达至身体的剩余各个部位，肌肉组织接收了这些信号。

想象一下在冷天的街角等待一辆迟来的公交车，你会冻得直发抖。其运作方式如下。

大脑的控制中心感知到你觉得寒冷。它向下通过脊髓向全身的神经发送信息，该信息在彼此相连的神经之间快速传递，然后从神经传达到肌肉组织。信息显示着：“注意！准备行动！”

当肌肉运动时，它会产生热量。这就是你跑步或者踢足球时身体会变暖的原因。当你的肌肉组织感知到身体觉得寒冷的信号时，它们就会忙碌起来。它们首先收缩，然后再放松，并且不停地收缩放松，这样就能使你发抖，并感到暖和些。

练习

1．发抖能帮助你的身体_________。

A．保持冷静

B．保持温暖

C．变凉

D．站直

2．神经系统包括_________。

A．一部分

B．三部分

C．两部分

D．很多部分

3．脊髓是一大束的________。

A．肌肉

B．脑细胞

C．神经

D．信号

4．神经会命令肌肉_________。

A．停止

B．放松

C．做好准备

D．变凉

5．当你颤抖时，你会感觉_________。

A．虚弱点

B．冷一点

C．强壮些

D．暖和些