The respiratory system is the process responsible for the transport and exchange of gases in and out of the human body. As we breathe in, oxygen in oxygen-containing air is drawn into the lungs through a series of air tubes known as airways. When air is drawn into the lungs and waste gases are expelled, it passes through the airways, first through the mouth or nose and then through the pharynx, larynx, and windpipe, also known as the windpipe. It then enters the lungs through the bronchi before finally reaching the alveoli. Inside the lungs, through a process known as diffusion, oxygen is transferred to the bloodstream through the alveoli (air ducts) where it is then carried inside the red blood cells and transported to the body's organs. At the same time as oxygen is absorbed by cells, waste products (carbon dioxide and water) are removed into the lungs where they are expelled during exhalation. When air is inhaled, it is moistened, warmed and cleaned. by tiny hairs called cilia within the respiratory system. These filter du...