Central Nervous System: The Central Nervous System

The nervous system is divided into the central nervous system (CNS) and the peripheral nervous system (PNS). The brain and spinal cord make up the CNS, and the PNS is made up of 31 pairs of spinal nerves, 12 pairs of cranial nerves and the autonomic nervous system. The CNS is the control system for the nervous centre, receiving and interpreting information and acting on that information. Information is sent to the CNS by receptors throughout the body. The nerves in the PNS send information from the receptors in the body to the CNS via afferent (sensory) nerves. The CNS sends actions to the muscles and glands via efferent nerves (motor). The efferent nerves are subdivided into those causing actions under conscious control i.e.voluntary
such as impulses which prompt movement of skeletal muscles, and those which are involuntary such as smooth tissue in the GI system, and cardiac tissue. The three main parts of the brain are the cerebrum, the cerebellum and the brain stem.