Question

How does gaseous exchange occur in the alveoli of lungs?

Answer 1

Hint: The tiny air sacs present towards the end of the bronchioles that serves as a major site for the exchange of carbon dioxide and oxygen with the bloodstream are called the alveoli.

Complete answer:
The process of gas exchange occurs during respiration in living organisms. Respiration is the phenomenon of the movement of oxygen from the outer atmosphere to the lungs and body tissues. In this process, carbon dioxide is also transported into the atmosphere from the body tissues. The exchange of gases occurs due to their concentration gradient. The primary parts of the lungs that play a role in this process are the alveoli and their capillaries.

The capillaries are tiny blood vessels that surround the alveoli and have thin walls. They are further connected to larger blood vessels called veins and thus, helps in the transportation of oxygen in our body. The trachea has branches which are called bronchi. These bronchi are further divided to form bronchioles. The termination of these bronchioles is done by alveoli. They are arranged in clusters in the lungs and are around millions in number.

The transportation of gases occurs through the process of diffusion or due to the difference in concentration gradients. The gases involved in this gaseous exchange are- oxygen and carbon dioxide. The air inhaled by the body has a higher concentration of oxygen and thus is diffused to the blood tissues. Whereas, the air present in the blood tissues have a higher concentration of carbon dioxide and thus are diffused to the alveoli. The thin walls of alveoli aids in this process. From the blood tissues, the oxygen is supplied to various organs and parts of the body. The carbon dioxide released from the body organs and parts are supplied to blood tissues and are further diffused into the alveoli. From the alveoli, these gases are moved out from the lungs and the trachea. These gases exchanged are moved to and fro in the lungs by the process of breathing.

Note: The process of moving air inside the lungs and expelling it out from the body after the gases are exchanged with the internal environment is called breathing. Animals take in oxygen and remove waste products like carbon dioxide through the process of breathing.