In humans, ventilation includes a coordinated effort of a number of muscles and buildings to move air into and out in the lungs. The principal muscle mass driving this process would be the diaphragm, a dome-formed muscle mass at The bottom from the lungs, separating the chest and abdominal cavities. https://andersonewlcr.humor-blog.com/36243762/the-basic-principles-of-ventilation-ductwork