EVERYDAY SCIENCE

Detailed explanation-1: -When you inhale (breathe in), air enters your lungs, and oxygen from that air moves to your blood. At the same time, carbon dioxide, a waste gas, moves from your blood to the lungs and is exhaled (breathed out). This process, called gas exchange, is essential to life.

Detailed explanation-2: -The lungs and respiratory system allow us to breathe. They bring oxygen into our bodies (called inspiration, or inhalation) and send carbon dioxide out (called expiration, or exhalation). This exchange of oxygen and carbon dioxide is called respiration.

Detailed explanation-3: -Tiny blood vessels surround each of the 300 million alveoli in the lungs. Oxygen moves across the walls of the air sacs, is picked up by the blood and carried to the rest of the body. Carbon dioxide or waste gas passes into the air sacs from the blood and is breathed out.

Detailed explanation-4: -When we breathe in, the millions of air sacs in the lungs fill with fresh oxygenated air. The oxygen then moves into the blood by passing first through the very thin walls of the air sacs and then into the capillaries, which are tiny blood vessels in a network within the lungs.

Detailed explanation-5: -Gas exchange takes place in the millions of alveoli in the lungs and the capillaries that envelop them. As shown below, inhaled oxygen moves from the alveoli to the blood in the capillaries, and carbon dioxide moves from the blood in the capillaries to the air in the alveoli.