In addition, a 17 monitor uses another 80 watts. That comes to 150 watts in an hour, or .15 kWh. If you have the same computer on for only 4 minutes (say, to check your e-mail), that would come to .01 kWh.
A Dr. Mehmet Oz, MD , Cardiology (Cardiovascular Disease), answered. The heart gets its own supply of blood from the coronary arteries. The two main coronary arteries (right and left) and their branches supply blood throughout the heart muscle. This animation explains how these arteries transport blood.
There are three different things that help blood get back to the heart. The three mechanisms are: venous valves, muscular pumps, and the respiratory pump. The blood in veins is at a lower pressure than it is in the arteries. The lower pressure makes for challenges getting that blood back to the heart. As there is less force (pressure) in the veins, blood would pool in the lower parts of the body if there were not mechanisms to prevent that.