Respiratory system (lungs, bronchi, trachea) on the left side, alveoli and their cellular components on the right side

The lungs supply oxygen to the rest of the body and remove carbon dioxide.

The lungs are made up of millions of tiny air sacs called alveoli.

Oxygen passes through the walls of these air sacs and is absorbed into the bloodstream. Carbon dioxide passes out of the alveoli to be released from the blood into the airways.

Each lung is divided into lobes and smaller subdivisions called segments.

The right lung consists of three lobes: upper, middle and lower, The left lung has only two: upper and lower.

Below you'll find tutorials and quizzes on the anatomy and physiology of the lungs, using interactive animations and diagrams. Learn more about the respiratory system with this quiz study guide.