What is the Function of the Human Central & Peripheral Nervous System? Understand the structure

The human nervous system is made up of organs that manage the affinity of communication signals in the body. It can be divided into central nervous system and peripheral nervous system.

This article will describe with respect to the structure of the central and peripheral nervous system in more detail. Keep reading to find out more.

For more info on the Nervous & Brain systems, please get here .

Table Of Content

On the structure of the central nervous system
#1 Brain
#2 Spinal cord
#3 Neurons, nerve cells that are the backbone of the human nervous system
On the structure of the peripheral nervous system
#1 Somatic nervous system
#2 The autonomic nervous system

On the structure of the central nervous system

Generally, the central nervous system consists of 3 main components namely:

1. The brain
2. Spinal cord
3. Nerve cells (neurons)

Since this system is a very important system for every individual, then it is protected from contact with the outside world.

What is more interesting is that even blood, which is an important element, has no contact with this structure.

The majority of the nutrients for this system are supplied by the cerebrospinal fluid that floods the organs of the central nervous system. It also acts as an additional protective mechanism for these organs. According To KhanAcademyIndia-English Nervous system (central & peripheral) | Control & Coordination | Biology

#1 Brain

The brain is an organ that is the control center for the entire human body.

It plays an important role in controlling various types of bodily functions such as thought processes, senses, movement, levels of consciousness and human memory.

The surface of the brain (also known as the cortex) has a concave pathway known as the sulcus.

The largest part of this organ of the nervous system is known as the cerebrum and it plays an important role in the processes of speech, behavior, thinking and memory.

The cerebrum of the brain is also divided into two hemispheres (right and left). The right hemisphere controls the movement of the body on the left and vice versa.

Maybe you have heard a statement that says a person uses the right hemisphere more than the left.

But scientific studies refute that statement. When it involves function, both sides of the brain work together to produce a body movement response.

The hemisphere of the brain can be divided into several lobes that have specific functions:

1. The frontal lobe is often associated with cognitive function, voluntary movement and language mastery skills
2. The occipital lobe has an important role in processing visual information
3. The parietal lobe plays an important role in processing sensory-related information
4. The temporal lobe is often associated with hearing and perception of sound. It is also important in processing human memory

Related Article: What are the Difference Between Sympathetic Nervous System And Parasympathetic Nervous

#2 Spinal cord

The spinal cord is a long tube-like structure starting at the end of the brain stem down to the waist area.

It is located in the human spine and has an important role in carrying information.

Interestingly with respect to this structure, it processes reflex movements without involving the brain.

This means, if you experience any reflexes (involuntary movements that occur immediately following a stimulus), you are not using the brain to process those movements.

Therefore, if you are in a situation like being touched by a hot kettle, your hands will move immediately before you feel pain.

It is a rescue response that does not require brain feedback that may be time-consuming.

#3 Neurons, nerve cells that are the backbone of the human nervous system

Many assume that nerve cells are found only in the brain and spinal cord. The fact is that these cells are present throughout the body.

It is an essential element in the human nervous system. Its presence allows for communication between the cells of the body to form a physical response.

The golden question that is often asked is how many neurons are there in our body? 1 million? 2 million?

Earlier, scientists had predicted that the brain alone had more than 100 billion neurons, but recent studies show that the number is not that many.

On average, humans have 86 a billion neurons. Although the number looks almost the same (14 billion difference), but the difference is the number of neurons found in the brain of mammals such as baboons or gorillas.

The difference is considered significant.

On the structure of the peripheral nervous system

The concept of understanding the peripheral nervous system is quite simple.

If the human brain and spinal cord form the central nervous system, then the peripheral nervous system is the nerve that splits from the central structure to supply signals to muscles and other organs.

It is like a tree:

1. The big trunk of a tree is the brain
2. The large branch of the tree is the spinal cord
3. Small branches (split from large branches) and twigs are peripheral nerves
4. Leaves/fruits are organs

The main role of the peripheral nervous system is to connect the central nervous system to the organs.

Generally, the peripheral nervous system is divided into two, namely:

1. Somatic nervous system
2. Autonomic nervous system

Each component of the peripheral nervous system plays an important role in regulating human physiological responses and functions.

#1 Somatic nervous system

The somatic nervous system is the part of the peripheral nervous system that is responsible for transmitting motor and sensory information from or to the brain.

The information sent or received by this system revolves around sensory information or voluntary movement.

Generally, it has two main types of neurons:

1. Neuron motor. These nerve cells are also known as efferent neurons. It carries information from the brain and spinal cord to muscle fibers found throughout the body. Motor neurons allow humans to take physical action after we experience a particular stimulus
2. Sensory neurons. These nerve cells are also known as afferent neurons. It carries information received through the sensory nerves to be processed by the organs of the central nervous system. These neurons are important because they allow us to process sensory information. As a result, feedback action can be received by efferent neurons to produce response

#2 The autonomic nervous system

The autonomic nervous system is one of the important components of the peripheral nervous system.

It is responsible for regulating body functions that cannot be voluntarily controlled such as blood flow, heart rate, digestive system and human respiratory system.

This system allows humans to control certain bodily functions without having to think about it.

For example, the heartbeat. You do not have to voluntarily control your heartbeat.

The rate can increase or decrease depending on the current situation. If every individual has to control this process voluntarily, then we cannot sleep for life.

Like the somatic nervous system, the autonomic nervous system is also divided into 2:

1. Parasympathetic system. This system helps to control normal body functions without having to use any physical resources. It usually acts after a person has been through a dangerous situation. When the threat is gone, this system will help the body to slow down the heart rate, respiratory rate, rate of blood flow to the muscles and narrow the pupils. Our body can return to normal function
2. Sympathetic system. The sympathetic system controls the ‘opponent or run’ response to prepare the body for going through a bitter moment or environmental threat. When an action requires energy (such as fighting), this system will speed up the heartbeat, increase respiration rate, prioritize blood flow to the muscles, activate the function of the sweat glands and open the pupils wider (dilation)


The central and peripheral nervous systems are the two main components that drive human biological functions.

The response to a stimulus requires both of these systems to process a life-saving response.

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