Why do we have to breathe? Our body is a very complex system. One of the main things it needs is energy. When we eat our body digests the food to get complex molecules like glucose, which it can use for energy. However, food alone isn't enough. The cells also need oxygen to react with the glucose to create the energy. We get the oxygen to our cells with the respiratory system and by breathing. Breathing In We breathe in using a muscle called the diaphragm. It flattens out making our lungs expand and fill with air. When we breathe in, air gets forced through our nose or mouth, down our windpipe, and into bronchi tubes in our lungs. These bronchi tubes branch out and get smaller and smaller, like the roots or branches of a tree. Alveoli No, these aren't a kind of pasta! At the end of the smallest branches of the bronchi are tiny air sacs called Alveoli. These air sacs have a very thin, one cell thick wall that allows oxygen to be passed to red blood cells as they are passing by. There are hundreds of millions of these tiny guys in our lungs. Breathing Out The Alveoli aren't done with just breathing in and passing Oxygen to our blood, they also pick up waste gas, or carbon dioxide, from our blood cells. When we need to breath out the carbon dioxide the diaphragm bows up and pushes the air back out of our lungs getting rid of the carbon dioxide and allowing fresh air with new oxygen to come back in on our next breath. 
Diagram of the Respiratory System Our Nose The nose does more for breathing than just providing a place for air to enter our body. It also helps to filter the air of dust and other stuff. It does this by using lots of hairs and mucus. It also helps warm up the air prior to getting to our lungs. Why do we get out of breath? When we run or do strenuous activity, our muscles burn energy and use up the oxygen in our red blood cells. To try and get more energy and oxygen our heart will pump faster to get more blood through the lungs. At the same time our lungs will try to breath harder and faster to get more oxygen. We end up feeling out of breath and have to take a rest so our bodies can recover. Talking The respiratory system also helps with talking. We couldn't talk without air. By forcing air through our vocal chords, the respiratory system helps them to vibrate and create sound like talking, singing, or shouting. More on the Human Body: Brain Nervous System Digestive System Sight and the Eye Hearing and the Ear Smelling and Tasting Skin Muscles Breathing Blood and Heart Bones List of Human Bones Back to Kids Science Page Back to Kids Study Page Back to Ducksters Kids Home Page |
|
