Anatomy and Physiology of the Lungs
The lungs consist of right and left sides (see illustration).
The right lung has three lobes:
The left lung has two lobes:
The heart sits in the mid chest extending into the left side
Starting from the trachea (windpipe), two large tubes known as bronchi (airways) separate and distribute air to the left and right sides of the lungs.
Bronchi gradually form from more generations, like a tree branch, and become smaller and smaller.
As they spread to the ends of the lungs they eventually form a grape-like structure known as the alveoli. (shown to the left)
The diaphragm is the large dome shaped muscle that contracts and relaxes during breathing. It also separates the chest and abdominal cavity. Muscles near our ribs also help expand our chest for breathing.