Nervous System Definition


Nervous system deals with the major functions of the body, it controls major body processes or systems including digestion, sexual development or puberty, etc. The nervous system also plays a vital role in controlling thoughts, memory, movements, and automatic motor response of the body. Nervous system can get damaged due to several external factors including viral infections, diseases, toxins, and the natural ageing process.

What is the Nervous System?

Nervous system is the complex system that acts as the command centre of human body. It helps to maintain the body system and experience the surroundings. The system comprises a vast network of nerves that sends signals to glands, muscles, and living cells of the entire body. The information is mainly collected from the brain and transmitted to other organs through nerves. It comprises specialized cells denoted as neurons. This helps to send signals, and messages within the body. After receiving signals from the brain individuals can able to sense everything through their sense organ and will be able to move their body parts as well.

Figure 1: Divisions of Nervous system

Parts of the Nervous System

The two major parts of nervous system include CNS and Peripheral nervous system as mentioned below.

  • Central nervous system (CNS): CNS is composed of the brain and spinal cord. Brain plays a vital role in transmitting information from brain to other vital organs within the body. The nerves are protected by an outer layer denoted as myelin, which helps to insulate the nerves and allows the information to get throughout the body.

  • Peripheral nervous system (PNS): The nerves that branch out from central nervous system make the peripheral nervous system which transmits messages or commands throughout the body. This system relays information from the spinal cord and brain to other major organs like arms, legs, toes, and fingers to make them move freely. This system is further divided into two main parts including, the Somatic nervous system and Autonomic nervous system.

Working principle of the Nervous System

Neurons are the basic unit of the nervous system that helps to control various activities.

  • Neurons are mainly of various types including motor neurons which allows the transmission of information from the brain to muscles and other vital organs of the body.

  • Sensory neurons helps to detect sound, light, taste, odour, heat sensation, and pressure and then send the messages to brain.

Figure 2: The architecture of neuron

  • The Nervous system controls all involuntary processes which include managing the rate of heartbeat, and releasing hormones like adrenaline. It also allows the pupils to open and respond to light and it helps in regulating the digestive system.

  • A Neuron sends commands to another neuron, it is denoted as it is sending an electrical signal to vital organs down the length of its axon. Electrical signal changes to chemical signal at the end of the axon. The axon then releases chemical signals with chemical messengers determined as neurotransmitters.

  • The system also consists of non-neuron cells denoted as Glia, which perform vital functions like protecting neurons, supporting and holding the neurons in their place. It also helps in creating insulation that is myelin which helps to move nerve impulses. It also trims out dead neurons and regulates neurotransmitters.

  • Human brains consists of about 100 billion neurons. Neurons are the cell body which incorporates axons, dendrites, and cell nucleus.

  • The nerve usually transports oxygenated blood throughout the body to maintain the body balance, equilibrium and metabolism.

  • Axons and dendrites allow these neurons to communicate across a greater distance within the body.

Disorders of the Nervous System and its Treatments

  • Various disorders of the nervous system gradually affect the entire body functions mainly the movement of limbs and arms.

  • Injured nerves experience trouble in sending messages to different parts of the body. The major causes of nerve damage includes Stroke, diseases like Cancers, infections, Diabetes, Lupus, and Rheumatoid arthritis.

  • A condition that is Multiple sclerosis mainly attacks the myelin layer of the nerve present in the CNS.

  • Other toxic substances can also affect the nervous system like Chemotherapy medicines, illegal drugs, alcohol, and tobacco. These cause nerve damage or Peripheral neuropathy.

  • Kidney diseases also develop in nerve damage over time. Disorders of the nervous system can be treated through various medications, regular exercises, and less consumption of life-threatening drugs, alcohol, and tobacco. A healthy diet and cruciferous vegetables can help to heal the damaged nerves if consumed every day.


Nervous system consists of two major parts including central nervous system(CNS) and peripheral nervous system. The brain is composed of various networks of communicating Glia and neurons. This specific network allows the parts of the brain to sense, talk with others, and control other body functions like thinking, emotions, behaviour, and movement. The aspects of human health usually get affected through feelings, memory, learning, sleep, breathing patterns, senses, and heartbeat rate. Toxic substances can also affect the nervous system like Chemotherapy medicines, illegal drugs, alcohol, and nicotine.


Q1. How the health of the nervous system is maintained?

Ans. Nervous system can get damaged due to viral infections, and diseases, like lupus and rheumatoid arthritis. It can also get damaged due to excessive consumption of tobacco, drugs, and alcohol. Nervous system can be kept healthy by exercising regularly, avoiding alcohol and tobacco, and having healthy foods.

Q2. What are the major parts of the Central nervous system?

Ans. The two major parts of the central nervous system (CNS) are the brain and spinal cord. CNS also consists of various nerve cells which are also denoted as neurons.

Q3. What are the symptoms of nervous system disorders?

Ans. The nervous system disorders include memory loss, lack of coordination, loss of tingling, and impaired mental ability. It can also be detected if the individual has a sudden onset of a headache, weakness, loss of muscle strength or muscle pain.

Updated on: 25-Jan-2023


Kickstart Your Career

Get certified by completing the course

Get Started