What happens to the heart tendons when a ventricle contracts?
When the heart is relaxed blood flows from the atria down through the valves and start filling up the ventricles. The atria then contract pushing the last volume of blood through into the ventricles and closing off the vessels that bring blood into the atria. The ventricles then contract and push the blood upwards but, since the valve flaps are hanging downwards, they get pushed up and close so that the blood has to exit via the aorta or the pulmonary artery. The heart tendons are long enough to allow the valve flaps to close but not long enough to let them pass that point where they would open up an entry into the atrium again. Imagine a swing door that can close to the point where the door is completely shut or can pass that point so that the door is open again. What the valve tendons do is prevent the “door” from passing that point. Sometimes the tendons can weaken and the flaps “invert” so that blood can backflow into the atrium. This obviously causes difficulties depending upon ho
