where does gas exchange occur in the lungs

gas exchange occurs in the alveolus of the lungs. Alveoli provide a good surface for gas exchange to take place.They provide a large surface area to volume ratio which increases the amount of gas that can be exchanged at a time. gases move between the alveoli and the blood through a process called diffusion. Oxygen moves from the alveoli in the lungs to the capillaries where it enters the bloodstream. Carbon dioxide diffuses from the capillaries to the alveoli. I would talk about the process of breathing, getting air into the lungs. I would talk about the importance of surface area to volume ratio and how this changes in smaller organisms. I would explain about the surface of the alveoli and how this helps with gas exchange.I would explain how O2 is carried by red blood cells and how these cells are adapted for gas exchange. I would aid their learning by getting them to draw a diagram of lungs and where alveoli are in the lungs and then an alveoli zoomed in to understand the structure of alveoli and how gases pass from here into the blood.