Human Respiratory System

Respiratory System Definition: 

Respiration is necessary for every living being, and there’s a distinct, special organ system working constantly to carry it out. In humans, it is called a respiratory system.

What is the Human Respiratory System?

The human body is a complex structure of many organs and organ systems, and the human respiratory system is one of them. The respiratory system functions continuously without a break, as we breathe by inhaling oxygen and exhaling carbon dioxide. Breathing is essential for our survival and effective for the functioning of all our organs. 

Human Respiratory System Diagram

If you carefully observe the respiratory system diagram, you will be able to see the various organs involved in its functioning. 

Features of the Human Respiratory System:

The structure of the lungs is created in such a way that it helps the exchange of gases. The other parts of the respiratory system include the nose, larynx, pharynx, trachea or the windpipe, bronchi, lungs, blood vessels, the airways for the passage of air, and the muscles that support the breathing. 

All these parts together form the respiratory tract that starts from the external nostrils and nasal chamber and goes up to the lungs.

Respiratory System Parts and Functions:


We inhale air through our nose which is the first step in the process of respiration.


These are two cartilaginous chords, situated at the joining point of pharynx and trachea.  They are also called the voice box.


The pharynx is a common path for the passage of both air and food, to their respective organ systems.


Trachea or the windpipe is like a long tube that takes the inhaled air into the further process. It is divided into left and right bronchi.


Bronchi are further subdivided into small, finer channels called bronchioles. These bronchioles have a balloon or bag-like structures at their ends that are known as alveoli.


Then there are lungs. The inhaled air is purified, and the oxygen necessary for all the body functioning is passed to various organs through the blood vessels. The exchange of oxygen and carbon dioxide takes place in small bags, alveoli. And the impure air of the carbon dioxide is exhaled out of the body through the same tract.

Respiratory Tract

The respiratory tract of the human respiratory system is a series of organs, starting from the external organs and going up to the internal ones. Each of these organs performs a distinct role in the respiratory system function.  

External Nostrils: The air is inhaled through the nostrils that pass through the nasal chamber, up to the common passage for both air and food called the pharynx.

Nasal Chamber: it has hairs and mucus that filters the air to remove the dirt.

Pharynx:  Because this is a common passage for passing both food and air, we cough sometimes when air and food particles get mixed. 

Larynx: The larynx can be called the soundbox of the human body that helps us in generating voice and sound, and thus helps us in communication. 

Epiglottis: The flap-like structure of epiglottis prevents food particles from going into the windpipe.

Trachea: A long passage that looks like a tube, and passes through the mid-thoracic cavity.

Bronchi: Bronchi are the two divisions of the trachea, one on the left and the other on right.

Bronchioles: Both the bronchi are divided into fine channels to whom we call bronchioles.

Alveoli: Can be called as air-bags, a balloon-like structure at the end of bronchioles.

Lungs: these sack-like organs are protected by a membrane called pleura.

Respiratory System Functions

The respiratory system function is a very important metabolic process in our body, that plays a crucial role in all living beings. 

Inhalation and Exhalation:

It begins by breathing and ends by exhalation, that’s the simplest explanation. But during and after these two acts, several processes are going on endlessly in our body.

Exchange of Gases Between Lungs and Bloodstream:

The oxygen is exchanged for carbon dioxide and is pumped through the bloodstreams.

Exchange of Gases Between Bloodstream and Body Tissues

The oxygen-carrying blood releases oxygen into body tissues, through the walls of capillaries.

The Vibration of the Vocal Cords

The larynx muscles move when we speak, creating sound and vibration. The same process happens during the exhalation also.

Olfaction or Smelling

When we inhale air, the chemicals present in the air activate the receptors of the nervous system on the cilia, and we can identify the smell.

Respiration in Humans

 The respiration in humans is divided into two types –

1. The external respiration consisting of inhalation and exhalation with the exchange of gases, and 

2. Internal respiration involves the exchange of gases between the blood and cells in the body. Lungs are the largest organ in the respiratory system.

FAQ (Frequently Asked Questions)

1. Does human respiration take place externally?

No, human respiration is a combined process that involves both internal and external respiration.

2. What is the main function of the respiratory system?

The main function of the respiratory system is to inhale the air, purify it, exchange the gases within the body, and exhale the carbon dioxide.

3. What is the purpose of oxygen in our bodies?

The oxygen is essential for the survival of human beings, and it is required for breaking down of glucose at the cellular level

4. Why is nose an important organ?

The nose is important as it acts as a defensive wall against all the external pathogens that try to enter our bodies.

5. Which part of the brain controls the respiratory system?

The medulla oblongata is the centre of the brain that controls the respiratory system.