Question

What is breathing? Explain the mechanism of breathing.

Answer 1

Hint: Breathing is defined as the process of intake of fresh air from the environment and expulsion of foul air from the body. It is carried by the different respiratory organs. Breathing This involves oxidation of complex substances into simpler ones. With the release of energy that is used in the body.

Complete answer:
When we breathe, we take oxygen inward from the air and give out carbon dioxide which is utilized by the plants. The process by which oxygen is taken in rich air is known as inhalation while the process of giving out carbon dioxide air is known as exhalation.
Breathing rate can be explained as the number of breathing per minute. It is inversely proportional to the size of the body of an organism. For example, the breathing rate that of an adult is 15-16 times in comparison to that of a new-born baby is 40-50 times.

The breathing mechanism is composed of two processes - inspiration and expiration.

1.Inspiration: It is defined as the process of intake of the atmospheric air. It associates the contraction of diaphragm and external intercostal muscles. The intercostal muscles are the muscles which are present intermediate and between the ribs. They are of 2 types- internal and external intercostal muscles. The internal intercostal muscles make the middle layer of intercostal muscles, while the external intercostal muscles develop on the interior surface of ribs.
It is usually an active process and completes in 2 second. When the radial muscle of diaphragm contracts, the diaphragm becomes flattened. As a result, intrapulmonary volume increases and the intrapulmonary pressure decreases. at the time when external intercostal muscles contract, ribs and sternum move upward and outward respectively. It results in increased intrapulmonary volume and increases intrapulmonary pressure. due to this environmental air enters into the lungs through the respiratory tract.

2.Expiration: It is defined as the process of giving out of air. It constitutes the relaxation of diaphragm and external intercostal muscles. It is a passive process and processed in 5 second. When the radial muscles of the diaphragm relax, it becomes dome-shaped. AS a result, intrapulmonary volume decreases and intrapulmonary pressure increases.
At the time When external intercostal muscles relax, ribs and sternum move downward and inward respectively. It also results in decrease of intrapulmonary volume and increases intrapulmonary pressure. So, air expels out of the lungs through the respiratory tract.

Note: At the time of forceful expiration, abdominal muscle and internal intercostal muscle contracts, which decreases the intrapulmonary volume and intrapulmonary pressure increases. Due to this, air expels out of the lungs. Breathing is a physical process while respiration also includes a biochemical process of oxidation of food.