Respiratory System Functions

Respiratory System Functions – an Overview

The respiratory system performs the significant role of supplying the body with oxygen and removing carbon dioxide. This system consists of various components. Each of these components plays an important part in the respiratory system functions.

The following discussion explains what is respiratory system. Read on to find information about how does the respiratory system work. Also learn about its components, interesting facts and respiratory system functions.

Respiratory System Structure

The system consists of the following main parts. They perform all the major functions of the respiratory system.


It is one of the external respiratory parts. The nose consists of the nasal cavity. It is the main opening which leads to the rest of the respiratory system. The nasal cavity is hollow and contains mucus and hair. The primary function of the nose is to make the air warm and moist. The mucus and hair also filter the air before it enters the lungs. So, nose is of great help in the overall role of respiratory system.


The mouth is the secondary opening leading to the lungs. It supplements the function of the nasal cavity. Alternatively, it also acts as a substitute in case of nasal blockage.


The pharynx is a muscular funnel. It transports air from the nasal cavity to the larynx.


The common name for trachea is the windpipe. It is five inches long and consists of C shaped rings of cartilage. It provides passage to the air when it passes from the larynx to the bronchi.


The trachea divides into two large air passages which are the bronchi. These bronchi carry air into the lungs.


The human body contains one pair of lungs. These are the major organ of the respiratory system. This is where the exchange of gases takes place between the respiratory system and the blood. The lungs consist of tiny air sacs, which are the alveoli.

These sacs provide a large surface area. So, there is the exchanges of considerable volume of gas within seconds.


The diaphragm plays an important role in the functions of the respiratory system. It is a muscle which helps the lungs expand and contract for the exchange of gases.

How does the Respiratory System Work?

Here is a summary of how the respiratory system works.

Exchanging Gases

It is necessary to maintain a constant supply of oxygen and removecarbon dioxide. This happens through the exchange of these gases between the body and the environment. Externally, exchange takes places through the nasal and oral cavities.

Internally, this exchange occurs between the lungs and the blood stream. As a result, an important one of the respiratory system functions reaches completion.

Filtering the Air

It is essential to filter the air before it reaches the lungs. Any dust particles or possible toxins are removed as these can damage the lungs. This filtering process takes place in the nasal cavity as well as the trachea and the bronchia.

These components of the respiratory system have a lining of cilia which trap dust and other small particles.


Breathing requires inhaling and exhaling of air. So, oxygen enters the respiratory tract while carbon dioxide leaves it. This process takes place with the help of the diaphragm which is a muscle. When this muscle relaxes, it pushes the air out of the lungs.

On the other hand, when it contracts, it creates sufficient room for the lungs to expand and receive air.

Supplying and Removing Gases

The supply of oxygen and removal of carbon dioxide takes place between the lungs and the blood. So, it is one of the important respiratory system functions. Such a process occurs through blood capillaries. In fact, numerous blood capillaries are found in the alveoli which facilitate this process.

Respiratory System Functions

Here are four major functions of respiratory system.

Pulmonary Ventilation

In simple words, pulmonary ventilation is inhalation and exhalation. This is the process of breathing. When we inhale, air travels through the nasal cavity or the mouth into the respiratory tract up to the lungs.

On the other hand, when we exhale, the air travels back from the lungs and out through the nasal cavity. This is one of the most important respiratory functions.Through this, you can maintain a fresh and constant supply of oxygen for the body.

At the same time, it removes carbon dioxide i.e. the byproduct of respiration.

External Respiration

This is the process by which gases travel between the lungs and the blood stream. It supplies oxygen from the lungs to the blood which then carries it to all other parts of the body.

Similarly, carbon dioxide travels from the blood to the lungs for exhalation. In this way, external respiration maintains the levels of oxygen in the blood and removes carbon dioxide promptly.

Internal Respiration

This process involves the exchange of oxygen and carbon dioxide between the bloodstream and various tissues of the body. In this way, there is a constant supply of fresh oxygen to the body tissues. At the same time, carbon dioxide goes out of the body.


Another of the important functions of respiratory system is olfaction. In simple words, you can call it smelling. Olfactory fibers are present in the nasal cavity which detect smell when air passes through the cavity.

The process of smelling is important for detecting potentially toxic substances. Alternatively, pleasant smells refresh the senses. Therefore, smelling is an important role of respirator system.

Respiratory System Facts

Here are some interesting facts about the respiratory system.

  • The surface area of the lungs is so large that you can compare its size to a tennis court.
  • Lengthwise, all the blood capillaries in the lungs measures up to 1,600 km.
  • The process of respiration produces carbon dioxide and vapors of water as byproducts. The total amount of water that changes to vapors during the whole day equals half a liter.
  • The breathing rate of children and women is fast than those of grown up men.
  • The lungs are the only organs of the body which can float on the surface of water. This is because each lung contains millions of alveoli containing air.
  • People who are habitual of breathing through the mouth can end up with crocked teeth. This is because breathing through the oral cavity can cause the jaws to shrink in size.
  • While at rest, our normal rate of breathing is twelve to fifteen times per minute.
  • Our lungs are not symmetrical. On the other hand, the left lung is smaller in size than the right lung. This is so that the heart can have sufficient room in the chest cavity.

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