It forms these two bronchi. We have the right bronchus and our left bronchus. And each one of these bronchies essentially terminate within each one of our two lungs. Now, each of these bronchies subdivides into smaller structures called bronchioles. And these bronchioles eventually terminate in a specialized sac structure known as our alveoli. So if we zoom in on the smallest bronchio that terminates inside the lungs, we basically get the following diagram.