Parts RESPIRATORY SYSTEM are two air tubes that branch off of the trachea and carry air directly into the lungs. Bronchi In the lungs oxygen is taken into the body and carbon dioxide is breathed out. Lungs the main organs of the respiratory system. Trachea The trachea filters the air we breathe and branches into the bronchi. Breathing starts with a dome-shaped muscle at the bottom of the lungs called the diaphragm is are Diaphragm sometimes called the windpipe.
