Now the trachea ultimately bifurcates, it divides into two bronchi. And each one of these bronchies subdivides into very tiny bronchioles that permeate through our lungs. And of each bronchio at the end of this very tiny air passageway are the alveolar sacs. And this is shown by this diagram. So structure number two is the bronchio that is shown in brown. It basically extends all the way into this space, number seven.