If you think about it, it is truly a wonder how our body inhales oxygen and exhales carbon dioxide. This is possible due to the respiratory system. This system in the body is what allows us to breathe and continue our lives. An average human being breathes fifty million times in his life! Structure influences the function of this intricate and beautiful system that keeps us alive. It all starts with the nose. The fundamental parts of the respiratory system are the lungs, nose, trachea, diaphragm and alveoli. When we inhale, the diaphragm, which is located under the lungs, relaxes, causing the lungs to inflate, allowing air from outside to pass through. We breathe in air through our nose and mouth. Small, fine hairs in our noses called cilia, filter the air for foreign particles and also wet and warm the air. This is because cold, dry air can irritate your lungs. The warm air then travels down the throat and into the windpipe. However, in the gorge, there are two passages. One for food and the other for air. A small flap of flesh known as the epiglottis opens and closes to let air through but not food. Next, the air passes through the trachea into the lungs. The trachea is one of the most crucial parts for the respiratory system. It is lined with 15 to 20 C-shaped rings of cartilage so that it does not collapse and block the passage of air. After the warm air passes through the trachea, it enters the lungs. The lungs have two parts, the left lung and the right lung. The left lung has three lobes while the right lung has two. In these five lobes there are branches called bronchi and small tubes called bronchioles branch off from the bronchi and then these bronchioles end in tiny lumps of air sacs known as alveoli. The alveoli are where there is little... in the center of the paper... with pure, clean air. The human body is the most complex and intelligent organism on planet Earth. The organ systems with it are wonderful and breathtaking. One of the most important systems of all is the respiratory one, as you have read, and without it we would not be able to survive. We will never stop breathing until we die and that, indeed, is a truly remarkable feat. Works mentioned "THE RESPIRATORY SYSTEM". Respiratory system. MJ Farabee, May 18, 2010. Web. January 22, 2014. “Body Systems.” : Respiratory system. Franklin Institute and Web. January 22, 2014. "The Respiratory System." - NHLBI, NIH. National Heart, Lung, and Blood Institute, July 17, 2012. Web. January 24, 2014. "Respiratory System Disorders." Respiratory system disorders. McGraw Hill and Web. January 23, 2014.Taylor, Tim. "Respiratory system". Inner body. Internal body and Web. 26 January. 2014.