There are valves in the heart which open and close that allow the blood to be pumped in one direction only. See the related link for more information.
diastole
gravity for those above your heart and valves for those below
Your heart keeps your blood "flowing"
The heart is the organ that keeps the blood flowing. Valves in the heart ensure the flow is only in one direction.
A clot
Valves
The heart valves keep blood from flowing backward. This increases the efficiency of the pumping of the heart.
The heart acts as a pump. When the heart beats, it pumps the blood in one direction.
I think that its important to exercise for your heart because it keeps the blood flowing throughout your body.
The bicuspid valve allows blood to pass from the heart to the aorta but then keeps it from flowing back into the heart.
They ensure that the blood flows only in one direction (back toward the heart).
No. Dancing gets your blood flowing and keeps your heart pumping at a healthy rate.