Nervous system

The central office at a telephone company and a control tower at an airport share similarities. Each is involved in communicating and coordinating many different activities and events. At the central office of a telephone company, messages are received and coordinated through a network of computers. This enables you to speak with a person who may be many miles away. At an airport control tower, air traffic controllers communicate important information to pilots and coordinate airport activities so that airplanes can take off and land safely.

Many activities in your body are controlled by different body systems. These activities are taking place each moment that you are alive. As you read this page, your eyes follow the words on the line. Your eyes move back and forth. You use your fingers to turn pages. These are two of the numerous activities that your body's control center coordinates.

Central Nervous System

Your body's control center is called the nervous system. The nervous system is the network of nerve cells that carries messages or impulses to and from the brain and spinal cord to all parts of the body.

The nervous system consists of the brain, the spinal cord, and branching nerves. Nerve tissue is composed of masses of nerve cells called neurons. Neurons may vary in size and shape, but they have common characteristics.

T he nervous system is divided into two major parts, the central nervous system and the peripheral nervous system. The central nervous system is composed of the brain and spinal cord.

The brain is considered to be the most complex part of the central nervous system and is protected in many ways from injury. It has its own kind of helmet called the cranium. The brain is also protected and nourished by three cushions called meninges. Meninges are membranes that surround the brain. Spaces between the meninges are filled with cerebrospinal fluid that further cushions the brain from blows. A concussion is a brain injury resulting from a severe blow to the head. Inner spaces of the brain, called ventricles, also hold fluid that helps protect the brain.

The spinal cord is like a thin cable that extends from the base of the brain about two-thirds of the way down the back. Like the brain, the spinal cord is well protected. It is surrounded by meninges and cerebrospinal fluid.

1.	nerve cells	нервові клітини
2.	to carry messages	передавати повідомлення
3.	brain	головний мозок
4.	spinal cord	спинний мозок
5.	branching nerves	відгалужені нерви
6.	neurons	нейрони
7.	central nervous system	центральна нервова система
8.	meninges	мозкова оболонка
9.	concussion	cтрус мозку
10.	cerebrospinal fluid	спинномозкова рідина