Final answer:
Diuretics and nitrate vasodilators are therapies used to reduce preload, which is the amount of blood returning to the heart. Diuretics increase urine volume, while nitrate vasodilators promote vasodilation and reduce blood flow and pressure.
Step-by-step explanation:
Diuretics and nitrate vasodilators are two types of therapies used to reduce preload, which is the amount of blood returning to the heart. Diuretics work by increasing urine volume, which leads to a reduction in blood volume and pressure. Nitrate vasodilators, such as nitroglycerine, relax the smooth muscle in the blood vessels, promoting vasodilation and reducing blood flow and pressure.