The human respiratory system helps us breathe. When we breathe in, air enters through our nose or mouth and goes down a tube called the trachea. This tube splits into two bronchi, which lead to the lungs. Inside the lungs, the bronchi divide into smaller tubes, ending in tiny air sacs called alveoli.
In the alveoli, oxygen from the air enters our blood, and carbon dioxide, a waste product, leaves the blood to be breathed out. The diaphragm, a muscle below the lungs, helps move air in and out, making sure we get the oxygen we need and get rid of carbon dioxide.
1.What is the main function of the respiratory system?
2.Which organ is primarily responsible for gas exchange in the respiratory system?
3.What are the tiny air sacs in the lungs where gas exchange occurs called?
4.What muscle helps the lungs to expand and contract during breathing?
5.What gas do we inhale from the air, and what gas do we exhale?