Understanding the Nervous System: Functions and Components

The Nervous System

The nervous system receives information from the receptors, processes and coordinates it, and generates orders to the effectors.

Central Nervous System (CNS)

The central nervous system coordinates all the body's functions. It is formed by the encephalon and the spinal cord.

The Encephalon

The encephalon is protected by the skull or cranium and by three membranes, the meninges, between which a liquid called the cerebrospinal fluid circulates. This liquid protects the encephalon from knocks and blows. The encephalon is divided into three parts: the brain, the cerebellum, and the brainstem.

• The brain is divided into two hemispheres, separated by a fissure. Its surface, called the cerebral cortex, is rough and full of folds and furrows, known as circumvolutions. The brain converts information into awareness and houses advanced functions like memory, intelligence, and will.
• The cerebellum controls balance and voluntary movements.
• The brainstem links the encephalon to the spinal cord and controls involuntary functions.

Spinal Cord

The spinal cord is a long, thin bundle of nerves protected by the spine, linking the encephalon to the rest of the body. It serves as a conduit for nerve impulses and coordinates reflex actions.

Peripheral Nervous System (PNS)

The peripheral nervous system links the CNS to the body's organs. It is formed by 31 pairs of spinal nerves and 12 cranial nerves. Nerves are divided into sensory and motor nerves. The PNS is divided into the somatic and autonomic nervous systems.

• The somatic PNS controls voluntary movements.
• The autonomic PNS regulates the activity of internal organs and controls involuntary movements. It is divided into the sympathetic and parasympathetic nervous systems, which act in opposite ways.