On any given day, at any given moment, blood flows through bodies, flesh and viscera, shaping our world from the inside out. The process is rather simple, I have been told: in the human body, blood is propelled by the heart, repetitively flowing from the right atrium and right ventricle, through the pulmonary system, into the left atrium, left ventricle, and aorta. It then unfurls into the rest of the body and back to our starting point, the right heart. (read more...)