Introduction

Abstract

The living organism is a very complex system. To stand up to the dangers of life, to feed, to digest, to procreate, to be born, to survive, to grow and to develop and — all the time — to remain in an equilibrium which is satisfactory, it needs the ability of quick decision and action. To be able to flee or fight, good internal communication is necessary. The higher the development of the living body, the more important such communication becomes. In the vertebrates, the mammals and the peak of creation, man, this sytem is most complex. The nervous system, comprising the brain, the spinal cord, the communicating motor and sensory nerves, supported by the sympathetic and parasympathetic nervous system, guarantee high-speed information and the ability to react. The transmission is by electric stimuli; the whole system is like a computerized telephone network.