Billions of nerve cells called neurons, interconnected to form a communication network in the body known about the nervous system. Neuron is the basic unit of the nervous system. Nouron elongated thin shape and deliver pulses of electricity to function, called nerve impulses.Neuron cell body is not much different from other cells. Neurons have many branches at the ends of his called dendrites, which receive the impulse of duty in the surrounding neurons. He also had axon or long nerve fibers, which function to deliver the nerve impulses to other nouron or to a muscle. Neurons are separated by a side by side in the narrow gap called the synapse. 

For centuries, the bones are considered as a dead structure that only serves to support the soft tissue surrounding active. The souls gradually realize that the bone alive and growing. Bone has its own blood vessels and is always built and reshaped.