OUR NERVOUS SYSTEM: The nervous system is a net of specialized cells called neurons that coordinate the actions and transmit signals between different parts of the body. It has two parts: .-The central nervous system contains the brain and the spinal cord. .-The peripheral nervous system. consists of nerves connected to the central nervous system. 1.- THE CENTRAL NERVOUS SYSTEM: It is composed by the brain and the spinal cord. 1.1.- The brain: weighs about 1.3 Kgs There are about 40 billion nerve cells, known as neurons, in the brain. Brain controls our body, receives, analyzes and stores information. The brain has three main parts: the cerebrum, the cerebellum, and the brain stem.
.- The cerebrum: is the largest part of the human brain, it gets information from the sense organs and controls intelligence, language, thinking, memory voluntary responses‌ .- The cerebellum: is the responsible for the the coordination of voluntary motor movement, balance and equilibrium and muscle tone (for example: for walking). .- The brain stem: is the region of the brain that connects the cerebrum with the spinal cord. The brain stem also controls life supporting autonomic functions like heart movements, breathing, digestion‌
1.2.- The spinal cord: The spinal cord is the main way for information connecting the brain and peripheral nervous system. It is protected by the spinal column. It is the responsible for the involuntary responses or reflexes. They permit to react very quick without thinking. For example when we cut or burn a finger, we remove it very fast.