We sat down after the training dive and Justin Wheeler and American Sports TV producer and I asked a few questions. My new understanding is that as peripheral vaso constriction increases with the surrounding water pressure, blood is forced to the thorax, feeding the heart and thence the brain. Residual gas volume in the lungs is drastically minimised, protecting them from damage. Here's what Gray's Anatomy says about the ravioli and their role. The human lungs are paired organs, located on either side of the heart and occupying a large portion of the chest cavity from the collarbone to the diaphragm.
Air enters the body through a series of passages, beginning with the nose or mouth.
It travels to the chest cavity through the trachea, which divides into two bronchi, each of which enters a lung. The bronchi divide and subdivide into a network of countless tubules. The smallest tubules, or bronchioles, enter cup-shaped air sacs known as alveoli, which number about 700 million in both lungs. Each alveolus is surrounded by a net of capillaries. As blood flows through these vessels, carbon dioxide passes into the alveoli, and oxygen diffuses into the bloodstream.