The respiratory system allows us to breathe by taking in oxygen and removing carbon dioxide. It contains key structures like the lungs, which get filled with oxygen and remove carbon dioxide, the larynx containing vocal cords, the trachea or windpipe connecting the mouth and nose to the lungs, and alveoli in the lungs where gas exchange occurs. The diaphragm helps with breathing by moving up and down to draw air in and out of the lungs.