The respiratory system is responsible for supplying our body with oxygen. It does this by enriching blood with oxygen every time we take a breath. It also removes carbon dioxide, which is a waste gas produced by the functions of the body, and other foreign matter that's useless or harmful to our bodies. The body parts that are a part of the respiratory system are the mouth, nose, trachea, lungs and diaphragm. Each of these plays an important role in how the human respiratory system works.
We draw oxygen into our respiratory system through the mouth or nose, which warm up the gas and moisten it before it enters the rest of the body. The oxygen then travels through the larynx (voice box) and down the trachea (windpipe) into the two bronchi, which are branch-like tissues that enter the lungs. Cilia, which are very fine hairs, grow in the larynx, trachea and bronchi. These hairs are coated with mucus that captures any germs and pollution that are in the air we breathe before it enters the lungs. This foreign matter is then expelled from the body through swallowing, coughing or sneezing.
Once the oxygen enters the lungs, it's sent to the rest of the body’s organs and tissues through a network of blood vessels. These blood vessels also capture any carbon dioxide emitted by the tissues as a metabolic waste. The lungs are made up of bronchioles, small tubes that have alveoli at their tips. Alveoli are very small round air sacs made up of capillaries, which are tiny blood vessels.
Blood is delivered around the body through a network of arteries, veins and blood vessels. The pulmonary artery delivers oxygen and removes carbon dioxide. It sends blood containing carbon dioxide to the alveoli, which expel the gas through exhalation. The alveoli replace the carbon dioxide with oxygen through inhalation. This oxygen-rich blood then travels to the heart, which pumps it to the rest of the body.
Respiration is the means for breathing in and out. As we breathe in, our chest muscles contract. This lifts the ribs out and moves the diaphragm down, expanding our chest cavity. This expansion decreases the air pressure in our lungs and allows them to be filled with air. As we breathe out, we reverse this process, which allows the lungs to push air containing waste products and foreign particles from our bodies.
