The human respiratory tract is made up of nostril, larynx, nasal chamber, pharynx, trachea, epiglottis,\xa0alveoli, bronchioles, bronchi and lungs.\xa0Within the lungs, the oxygen is exchanged for carbon dioxide waste through millions of microscopic sacs known as alveoli.\xa0The oxygen inhaled diffuses into the capillaries of the lungs, binds to the haemoglobin and is pumped into the bloodstream.\xa0The carbon dioxide from the blood diffuses through the alveoli and is expelled by exhalation.The alveoli are thin-walled and richly supplied with a network of blood vessels to facilitate the exchange of gases between blood and the air-filled in alveoli. They have a balloon-like structure that provides maximum surface area for exchange of gases.

Alveolies are balloon like structures filled with blood which helps in the exchange of gases
Alveoli carries out the the process of e exchange of gases as the tiny blood vessel present in the wall of the alveoli . By lifting our ribs and flatten the diaphragm , the chest cavity be come spacious . Air is sucked into lungs and alveoli . The oxygen from the berth , diffuses into blood and C02 from the blood brought from the body , diffuses out in the body….