C12 - The Respiratory System

Gas exchange occurs at the site of the

Lungs contract and expand and are controlled by the

Energy comes from __________, which is a simple sugar we get from food. Glucose is taken into the bloodstream and into cells to produce ATP by the mitochondria.

Diffusion is when gas particles, like oxygen or carbon dioxide, move from

Diffusion can occur through a membrane if the particles are ______ to get through it.