Final answer:
Resistance to flow or impedance to ventricular ejection is referred to as afterload.
Step-by-step explanation:
The resistance to flow or impedance to ventricular ejection is referred to as afterload. Afterload is the tension that the ventricles must develop to pump blood effectively against the resistance in the vascular system. Any condition that increases resistance requires a greater afterload to force open the semilunar valves and pump the blood. Damage to the valves, such as stenosis, which makes them harder to open, will also increase afterload.