(单词翻译:单击)
Today we will talk about an organ that rules all of our body and that is our brain.
今天我们将谈论一个支配我们全身的器官，那就是我们的大脑。
As it is the most sensitive organ, our brain is kept inside the bony covering called skull.
因为它是最敏感的器官，我们的大脑被保存在叫做颅骨的骨质覆盖物中。
From doing physical activity to solving logical problems, from dealing with emotions and feelings to creativity, brain is responsible for all.
从进行身体活动到解决逻辑问题，从处理情绪和感受到创造，大脑负责所有事情。
Therefore, it never sleeps.
因此，它从不睡觉。
Our brain can be divided into three main parts; the cerebrum, the cerebellum and brain stem.
我们的大脑可以分为三个主要部分：大脑、小脑和脑干。
Cerebrum is the largest part of brain, which can be further divided into right and left halves called hemisphere.
大脑是人脑中最大的部分，可进一步分为左右两半，称为大脑半球。
Each cerebral hemisphere has four lobes namely frontal lobe, parietal lobe, occipital lobe and temporal lobe.
每个大脑半球有四个脑叶，即额叶、顶叶、枕叶和颞叶。
Each lobe performs different functions.
每个“叶”执行不同的功能。
Cerebellum is responsible for movement and coordination.
小脑负责运动和协调。
It gives you sense of balance and thus prevents you from falling down.
它给你平衡感，防止你摔倒。
Brain stem includes mid brain, pons and medulla oblongata.
脑干包括中脑、脑桥和延髓。
It controls your body's involuntary actions like breathing, heart rate and blood pressure.
它控制着你身体的无意识动作，比如呼吸、心率和血压。
Brain comes under a system called nervous system.
大脑隶属于一个叫做神经系统的系统。
Structurally, nervous system is classified into two types: Central Nervous System (CNS); and Peripheral Nervous System (PNS);
从结构上讲，神经系统分为两类：中枢神经系统和周围神经系统。
The Central Nervous System comprises of the brain and spinal cord.
中枢神经系统由大脑和脊髓组成。
The spinal cord is the bridge that connects the brain to peripheral nervous system.
脊髓是连接大脑和周围神经系统的桥梁。
It starts from medulla oblongata and stretches to lumbar region of the spine or vertebral column.
它从延髓开始，延伸到脊柱或脊柱的腰部。
The Peripheral Nervous System is a network of nerves spread across our body.
外周神经系统是遍布全身的神经网络。
Think of Peripheral Nervous System as a network of highway that connects the body with Central Nervous System.
把外周神经系统想象成连接身体和中枢神经系统的高速公路网。
This highway has two way traffic.
这条高速公路是双向通行的。
Let's see how.
让我们看看是如何做到的。
When you hold a hot cup of coffee, sensory neurons in your hand transmit signal to brain through sensory neurons, also called afferent neurons, that the cup is hot.
当你拿着一杯热咖啡时，你手中的感觉神经元通过感觉神经元（也称为传入神经元）向大脑传递信号，水杯是热的。
Your brain process that information and send response through motor neurons, known as efferent neurons, that you must put that cup back.
你的大脑处理这些信息，并通过运动神经元（也称为传出神经元）发送反应，你必须把杯子放回去。
PNS consists of total 43 pairs of nerve, among which 12 originate in brain, named as cranial nerves and 31 originate from spinal cord, hence called as spinal nerves.
周围神经系统由43对神经组成，其中12对起源于脑，称为脑神经，31对起源于脊髓，故称为脊神经。
Here you hear the word “neuron”.
在这里，你会听到“神经元”这个词。
Neuron is the basic unit of nervous system.
神经元是神经系统的基本单位。
It is the nerve cell which transmit electrical signals to brain.
它是将电信号传递给大脑的神经细胞。
A neuron has three parts: Dendrites, soma or cell body, and axon.
神经元有三部分：树突、胞体和轴突。
Dendrites serve as input device for neuron because it receives input from other nerve cells.
树突是神经元的输入装置，因为它接受来自其他神经细胞的输入。
Soma or cell body of neuron contains nucleus.
神经元的胞体含有细胞核。
Axon serve as output device from where it transmit electrical response to other neurons.
轴突作为输出装置，将电反应传递给其他神经元。
I hope this helps you in understanding nervous system.
我希望这个视频能帮助你了解神经系统。
