Medical Science / Medicine Essay

Main Functions of the Nervous System

The nervous system is one of the most complex systems in the human body. It is also highly essential and primarily made-up of different functionally interlinked parts that actively work together to carry out all the mental functions that properly coordinate the whole human body system (Tortora & Derrickson, 2016).

This system (i.e the nervous system) is chiefly responsible for the control of both the voluntary and involuntary operations in the human body. The nervous system is also concerned with the transmission of neural signals from one organ in the human body to another.

The nervous system performs a lot of important roles that invariably help in coordinating the whole body system (Barclay, 2020). This is why, in this article, our main purpose would be to answer the question; what are the main functions of the nervous system? But before we do that, let us first examine the operation of the nervous system: how does the nervous system work?

Operations of the Nervous System

As mentioned earlier, the nervous system consists of different parts that work together, namely; the human brain, the spinal cord, our sensory organs, and the neurons that are particularly responsible for transmitting impulses from a part of the human body to other parts (Barclay, 2020).

The nervous system is also chiefly made up of what is referred to as the "nerve cells" (also called neurons). In turn, this also consists of the cell body (or soma) and different other smaller extensions (or sections) that can either be described as axons or dendrites (Kandel, Schwartz & Jessel, 2000).

The extensions that are nearer to the cell body, commonly described as dendrites, are generally designed to receive stimuli. Axons can be either one or more, and they usually contain myelin sheath; this is a lipid material that covers the lengthy axon and is also responsible for the quick transmission of electrochemical information to other neurons or effector cells in the system (Kandel, Schwartz & Jessel, 2000).

A "collection" of axons is either referred to as tracts or nerves depending on where they're located. In the nervous system, we also have the glial cells (Noback et al, 2005). These are specially designed cells that work in manufacturing myelin, supplying oxygen, and also providing mechanical support for the nervous system (BD Editors, 2019). In addition, they also protect the nervous system from pathogens, regulating the extracellular fluid in the human brain and also providing nutrients to the neurons.

Basically, the neurons in the nervous system can collectively create connections to produce networks and circuits for the transfer, reception, and storage of information (stimuli and responses).

The Three Main Functions

The nervous system is a highly integrated operation in the body. Based on this, its main functions are usually classified into three, namely; sensory input, motor output, and integration (information processing) (Ebneshahidi, 2006). Now, let's go ahead to look at these main functions one after the other.

Sensory Input

The sensory (also afferent) input derived from the sensory receptors that monitor external and internal changes of the body (stimuli) (Ebneshahidi, 2006). The information received is then immediately transferred to either of the two main organs in the nervous system, which are; the brain and the spinal cord (Mai & Paxinos, 2011). This information or the sensory input is then quickly processed and interpreted by the nervous system to generate a response which will also be quickly sent back to the body parts. This response (what is referred to as the motor output) is also activated by the nervous system through the muscles and glands in the body (Mandal, 2019).


Integration or information processing is the next function the nervous system performs (Ebneshahidi, 2006). Its main function at this stage is to regulate and transfer the information received to the body parts. It first interprets the message gathered from the sensory neurons (Ebneshahidi, 2006). Afterward, the message is then sent back throughout the body parts. It exactly at the stage that an appropriate response to the stimuli or sensory input is determined (Mai & Paxinos, 2011).

Motor Output

Immediately the response for the sensory input has been processed, the nervous system transmits signals to the effector organ, either the muscles or glands, through what is called the motor output to activate the response (Mai & Paxinos, 2011).

In all, our nervous system allows for the reactions and abstractions we have of our immediate society, which is why discrepancies (or distinctions) generally exist in the way humans usually react to external, as well as internal stimuli.

The aim of this article was to answer the question, what main functions of the nervous system? And to answer this question, the three main functions mentioned above have been given.

Typically, it is on these three that other neural processes of the nervous system primarily rely on for the transmission of sensory information, from the body parts (effectors) to the brain or spinal cord, and back to the body parts again. 


Barclay, T. (2020). Nervous System. Retrieved from

BD Editors (2019). Nervous System. Retrieved from

Ebneshahidi, A. (2006). The Nervous System & Nervous tissue. Pearson Education Inc.

Mai, J. & Paxinos, G. (eds.) (2011). The Human Nervous System (3rd ed.). Academic Press. Retrieved from

Mandal, A. (2019). Function of the Nervous System. Cashin-Garbutt (ed). Retrieved from

Noback, C. R., Strominger, N. L., Demarest, R. J. & Ruggiero, David A. (2005). The Human Nervous System: Structure and Function (4th ed.). Humana Press. DOI:

Kandel E. R., Schwartz J. H. & Jessel T. M. (eds.) (2000). "Ch. 2: Nerve cells and behavior". Principles of Neural Science. New York: McGraw-Hill Professional Division. Retrieved from

Kandel E. R., Schwartz J. H. & Jessel T. M. (eds.) (2000). "Ch. 4: The cytology of neurons". Principles of Neural Science. New York: McGraw-Hill Professional Division. Retrieved from

TortoraMain Functions of the Nervous System, G. J. & Derrickson B. H. (2016). Principles of Anatomy and Physiology. WileyPLUS.

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