The nervous system is broken down into two major divisions: the central and the peripheral nervous system. Despite their close association, the two systems are responsible for different bodily functions. This article draws the line between them.

Summary Table

Definitions

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The central nervous system (CNS) is one of the two components of the nervous system. It is made up of the brain and the spinal cord and it plays a major role in the integration of all the information sent by the different parts of the body. It also coordinates bodily activities, which are influenced by internal and external factors.

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Meanwhile, the peripheral nervous system (PNS) is the part of the nervous system that is located outside the the spinal cord and the brain. Made up of ganglia and nerves, it is mainly responsible for connecting the sensory organs, glands, blood vessels, and different organs to the central nervous system.

Central vs Peripheral Nervous System

Although they both play a critical role in maintaining normal bodily functions, there is a major difference between the central and the peripheral nervous system.

Structure

The central nervous system (CNS) is made up of the brain and the spinal cord. The peripheral nervous system (PNS), on the other hand, is further divided into two systems: the autonomic and the somatic nervous system. The autonomic nervous system is responsible for regulating involuntary bodily functions such as respiration, heart rate, and immune responses, while the somatic nervous system controls voluntary responses. The major composition of the PNS includes cranial nerves, spinal nerves and roots, and autonomic nerves.

Protective Barrier

The structures within the CNS have a protective barrier. The cranium, which is a part of the skull, encapsulates and protects the brain while the vertebrae protects the spinal cord. The vertebrae is a series of bones that form and shape the backbone. Unlike the brain and the spinal cord, the nerves and ganglia that make up the PNS are not protected by any bodily structure and are therefore more susceptible to injury.

Main Function

The CNS performs multiple roles to maintain homeostasis and ensure normal bodily function. As the main core of perception, emotion, and thought processes, the CNS integrates and responds to sensory information from different parts of the body. The spinal cord regulates musculoskeletal reflexes and acts as a pathway for signals between the body and the brain. The brain, on the other hand, integrates sensory information and coordinates the voluntary and involuntary functions of the body.

Meanwhile, the PNS is mainly responsible for transmitting information between the brain and the different structures of the body, especially the most distal parts. It is made up of two types of cells: the sensory and the motor nervous cells. The sensory nervous cells convey information from external stimuli and internal organs to the CNS, while the motor nervous cells carry responses from the CNS to the body’s organs, glands, and muscles.

Recovery from Injury

The CNS is mostly made up of specialized cells that are not capable of dividing and regenerating, making recovery from an injury extremely difficult. Since the CNS is made up of a very complex network, recreating and mimicking the system after the injury is challenging. Recovery from damage to the PNS, on the other hand, is highly dependent on the extent of injury. Peripheral nerves may or may not recover after a trauma.