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 ...

The simplest way to imagine this respiratory system is as an inverted tree: a large trunk (the trachea) branches over and over again (bronchioles), ending in tiny leaves (alveoli) that perform the ...

To understand COPD’s pathophysiology, it’s important to understand the structure of the lungs and how they work: When you inhale, air moves down your trachea and then through two tubes called ...