The trachea divides into two tubes called the bronchi. The bronchi divides into many tubes called bronchioles. The bronchioles divide until they end up in tiny air sacs called alveoli. There are ...

What these tiny sacs in the lungs do and conditions that can affect them Medically reviewed by Susan Russell, MD Alveoli are ...

Anatomy of the respiratory system, showing the trachea and both lungs and their lobes and airways. Lymph nodes and the diaphragm are also shown. Oxygen is inhaled into the lungs and passes through the ...