Divisions of the Nervous System
The nervous system may be divided into (a) the central nervous system, made up of the brain and spinal cord, and (b) the peripheral nervous system, consisting of the peripheral nerves and the ganglia associated with them.
The brain consists of (a) the cerebrum, made up of two large cerebral hemispheres, (b) the cerebellum, (c) the midbrain, (d) the pons, and (e) the medulla oblongata. The midbrain, ponsand medulla together form the brainstem. The medulla is continuous, below, with the spinal cord.
Peripheral nerves attached to the brain are called cranial nerves; and those attached to the spinal cord are called spinal nerves.
The peripheral nerves include those that supply skin, muscles and joints of the body wall and limbs, and those that supply visceral structures e.g., heart, lungs, stomach etc. Each of these sets of peripheral nerves is intimately associated with the brain and spinal cord. The nerves supplying the body wall and limbs are often called cerebrospinal nerves. The nerves supplying the viscera, along with the parts of the brain and spinal cord related to them, constitute the autonomicnervous system. The autonomic nervous system is subdivided into two major parts: the sympathetic and the parasympathetic nervous systems.