Explain the Mechanism of Breathing in Human Beings

Breathing Definition

Breathing is the process by which air rich in oxygen is taken inside the body of human being and air rich in carbon dioxide is expelled from the body (with the help of breathing organs)

A breath means one Inhalation plus one Exhalation.

Breathing mechanism  in Human Beings involves three following steps

Inhalation –

Process by which Inhalation occurs during Breathing
  • Air is taken into the body through nostrils where it is filtered by hair and mucus.
  • Air then passes down through the trachea.
  • When we breathe in, ribs move up and flatten the diaphragm, due to which the chest cavity becomes larger.
  • Expansion of the chest cavity creates a partial vacuum in the chest cavity.
  • As a result, air is sucked into the lungs and fills the expanded alveoli.

Gaseous exchange

Gas Exchange process
  • The walls of alveoli contain an extensive network of blood vessels.
  • Hemoglobin is the respiratory pigment present in blood binds with oxygen and carries it along the blood in the body.
  • As blood passes through the tissues of the body oxygen from the blood diffuses into the cell, whereas carbon dioxide which is produced during respiration diffuses into the blood from tissues.
  • Blood releases carbon dioxide into alveoli  In the lungs that it brings from the whole body for expiration.


Exhalation process in Human beings
  • It is the process in which carbon dioxide from the lungs is given out in the atmosphere.
  • The carbon dioxide which is transported in dissolved form in blood from the whole body is passed to the alveoli.
  • Chest cavity is compressed due to relaxation of ribs and diaphragm. Ribs move down and diaphragm becomes dome shaped decreasing the chest cavity.
  • Does push the air out from the lungs to  the atmosphere.

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