Diseases that can affect these airways include: Your airways branch into tiny tubes (bronchioles) that end in clusters of air sacs called alveoli. These air sacs make up most of your lung tissue.

It travels down the trachea – or windpipe – into one of two bronchi and into bronchioles before entering one of millions of alveoli, where gaseous exchange takes place. When we breathe out ...

The bronchi branch out into smaller tubes called bronchioles. At the ends of the bronchioles are little air sacs called alveoli. At the end of the alveoli are capillaries, which are tiny blood ...