Question

Describe the mechanism of respiration in humans.

Answer 1

Hint: Respiration is a biochemical process. During respiration, the cells of an organism obtain energy by combining oxygen and glucose. As a result, it releases carbon dioxide, water, and ATP (the currency of energy in cells). The normal respiration rate of a normal adult person at rest ranges from 12 to 16 breaths per minute.

Complete answer:
The mechanism of respiration in man occurs in two phases:
- Inspiration
- Expiration.

> Inspiration is the process in which air is inhaled into the lungs. During this process, the muscles of the diaphragm contract, and the diaphragm moves downward. This result of inspiration is an increase in the volume of the chest cavity and a decrease in the air pressure inside the chest cavity. Therefore, the oxygenated air present outside the body being at high-pressure flows rapidly into the lungs. Then, the oxygenated air reaches the alveoli. Alveoli of the lungs are thinly walled structures and are surrounded by a network of blood capillaries. The oxygen passes through the walls of the alveoli into the blood of blood capillaries. The oxygen is then distributed to all the tissues of the body. The waste product i.e carbon dioxide is absorbed from the tissues, by blood and carried to the alveoli of the lungs for expiration.

> Expiration is referred to as the process of exhaling air from the lungs. During this process, the muscles of the diaphragm relax and the diaphragm moves upward. This result is a decrease in the volume of the chest cavity and an increase in the air pressure inside the chest cavity. This pushes out carbon dioxide outside the body.

Additional information:
The force of inspiration and expiration can be increased by use of the muscles of the abdomen. A healthy human breathes 12-16 times in a minute on an average.
The volume of air in breathing movements can be estimated with a spirometer .
Spirometry helps in assessment of pulmonary function.

Note: They are four types of respiration-
- Breathing or ventilation - Exchange of gases with the internal environment.
- External Respiration - it is the exchange of gases (oxygen and carbon dioxide) between inhaled air and the blood.
- Internal Respiration - it is the exchange of gases between the blood and tissue fluids.
- Cellular Respiration - It is a set of metabolic reactions and processes that take place in the cells of organisms to convert biochemicals.