Answers.com > Wiki Answers > Categories > Science > Biology > Human Physiology > Circulatory System > Heart > What prevents blood from flowing back into ... wiki.answers.com |
supercool73, There is no valve, as such, but backflow is prevented by the opening of the tricuspid valve, thereby lowering the pressure in the right ... answers.yahoo.com |
Like everything else, blood is subject to the forces of gravity. Yet blood sometimes must circulate against gravity -- moving "uphill" from your legs to your heart, ... www.sharecare.com |