arterioles
A clot
Heart blood vessels is what collects blood and pumps it to the lower chamber. This is what keeps the heart in working function.
It means the boil keeps returning.
Arteries have no valves to prevent the blood from flowing backwards, but it is unnecessary when the heart keeps pumping. The blood pressure is highest when the blood is leaving the heart chamber into arteries -- the heart pumping keeps blood going one-way in the arteries.
The natural flow of the blood stream in the human body. (ie: pressure, resistance)
A boomerang (or a really bad relationship!)
A specific chamber? It's valves and each one has a different name. I'll list the chamber and the valve which stops 'backflow':- Right Atrium: Tricuspid valve Right Ventricle: Pulmonary valve Left Atrium: Mitral valve Left Ventricle: Aortic valve The valves basically open when the relevant chamber is pumped but when pressure goes back towards the chamber they snap shut, stopping blood from going back through the heart/circulatory system.
The pumping of the heart keeps the blood moving
Motive (alternate spelling: motif)
He does not rule, he guards the Gates and keeps the ghosts from returning to the Earth.
It is necessary for blood to pump through your body because it keeps you alive. It sends the blood to your organs and keeps them from failing.
blood donation