How does the circulatory system work? There are obviously main arteries taking blood at pressure to the limbs & capillaries taking it to the extremities, but how does the blood get back once it’s there? Why don’t we have giant blood balloon hands & feet?

We need a VR app that does for the human body what google earth VR does for geography. I learned more in a few hours on google earth than I did my entire time in school.