The heart is the organ that keeps the blood flowing. Valves in the heart ensure the flow is only in one direction.
The heart acts as a pump. When the heart beats, it pumps the blood in one direction.
One directional valves keep blood in the heart flowing in the right direction. There are three valves: biscupid valve, semilunar valve and tricuspid valve. These open to let the blood flow through then close to prevent the blood flowing back in the wrong direction making the heart less efficient.
These are valves, and are found in veins to prevent blood from flowing backwards.
They ensure that the blood flows only in one direction (back toward the heart).
it keeps your blood flowing
Your heart keeps your blood "flowing"
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.
A clot
The heart has valves for to allow blood flow in one direction only. They close as the blood passes each. Hooweestik.
it keeps blood flowing
Valves