In class, we briefly discussed the physiology of the respiratory system within animals. I decided to look into some papers that involved the respiratory system. I eventually came across an old paper that talked about how exposing the lungs to different forms of silica can lead to increase tissue production. Originally this was thought to have been a possible therapeutic, however, when the authors decided to run these experiments on mice, most died. However, some rats did experience increase tissue production. If you are curious about this topic, I have provided a link.