Difference Between Inhalation and Exhalation

Table of Contents

Main Difference

The main difference between inhalation and exhalation is that inhalation is a process of intake of air or oxygen into the lungs while exhalation is a process of giving out of air or carbon dioxide through the lungs.

Inhalation vs. Exhalation

Breathing is a characteristic of life. All the living organisms breath to get useful gases and to release harmful gases from the body. The intake of air or oxygen into the lungs is known as inhalation while the process of releasing carbon dioxide is known as exhalation. A single breath comprises one complete inhalation and exhalation process. The breathing rate varies from person to person and according to their daily activities. The average breathing rate of a common person is 15 to 18 times per minute. During heavy exercise or running etc. it may increase to 25 times per minute. The volume of the lung increases during inhalation while the process of exhalation deflated them. The diaphragm also plays its role in breathing. It contracts and gets flatten by moving down during inhalation while it relaxes and become dome-shaped by moving up during exhalation.

Comparison Chart

Inhalation	Exhalation
A process of intake of air in the lungs is known as inhalation.	A process of releasing air through the lungs is known as exhalation.
Gasses
Living organisms inhale air comprises of oxygen and nitrogen gasses.	Living organisms exhale air comprises carbon dioxide and nitrogen.
Process
It is an active process.	It is a passive process.
Chest Cavity
During inhalation, the size of the chest cavity increases.	During exhalation, the size of the chest cavity decreases.
Lungs
The volume of lungs increases during inhalation.	The volume of lungs decreases during exhalation.
Diaphragm
The diaphragm contract and get flatten during the inhalation process.	Exhalation process relaxes the diaphragm, and it becomes dome-shaped.
Muscles
During inhalation, the internal intercostal muscles relax while external costal muscles contract.	During exhalation, external costal muscles relax while the internal intercostal muscles contract.
Rib Cage
Due to the movement of the intercostal muscles rib cage moves upward and outward.	Due to the movement of the intercostal muscles rib cage moves downward.

What is Inhalation?

Inhalation is also known as inspiration and referred to as “Breathing in”. It happens automatically and can be consciously controlled but within limits. Inhalation is a part of the cycle of breathing. It involves the intake of air through nostrils. Air rich with oxygen passes through the nasal cavity and reaches the lungs. The lungs are found in the chest cavity and are surrounded by the rib cage. The diaphragm which is a large muscular sheet located on the bottom of the cavity. During inhalation, when air reaches in lungs, diaphragm contracts and moves downward. So, it increases the space in the chest cavity and provides space to the lungs to expand. The internal intercostal muscles of the ribs relax while external costal muscles contract during inhalation. It pulls the rib cage both upward and outward and increases the space of the chest cavity. From the lungs, oxygen after passing through bronchial tubes reaches the alveoli. The oxygen or air reaches the blood vessels by passing through the thin walls of alveoli. Hemoglobin in blood vessels carries the oxygen and moves it throughout the body.

What is Exhalation?

Exhalation is also known as “Breathing out”. This process is entirely opposite to the inhalation process. The volume of the lungs decreases. The diaphragm relaxes and becomes dome-shaped. Intercostal muscles of the rib cage also relax. So, all these things combine to reduce the size of the chest cavity. These steps force carbon dioxide rich air out of the lungs and windpipe and finally out of the body through the nose.

Key Differences

A process of intake of air in the lungs is known as inhalation while a process of releasing air through the lungs is known as exhalation.

Inhalation is an active process whereas exhalation is a passive process.

Inhalation involves the intake of air comprises of oxygen and nitrogen in excess while exhalation involves the removal of air rich in carbon dioxide and nitrogen.

The volume of lungs increases during inhalation but the volume of lungs decreases during exhalation.

The diaphragm contracts during inhalation whereas it relaxes during exhalation.

Due to the movement of intercostal muscles rib cage moves upward and outward during inhalation while it moves downward during exhalation.

Space of the chest cavity increases during inhalation while it decreases during exhalation.

Conclusion

From the above discussion, it is concluded that Inhalation is a “breathing in” process in which oxygen-rich air is intake by lungs while exhalation is a” breathing out” process in which the lungs release carbon dioxide rich air through the body.

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