Blood vessels have valves that act like doors really. Also blood is pumped (pushed) out and around your body by each pump of your heart, each pump pushes more blood through, there is nowhere else to go but forward. It doesn't suck it back .
veins contain valves that prevents blood flowing backwards between heartbeats.There are valves in the veins that stop the blood from flowing backwards.
Blood veins have valves that prevent blood from flowing backwards.
Veins have valves which stop the blood from flowing backwards
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.
Valves
no
There are valves in the heart - and the larger blood vessels that stop the blood flowing backwards.
yes with valves
valve
Pressure There are also one way valves in the circulatory system.
it keeps your blood flowing
Your heart keeps your blood "flowing"