Cardiovascular System

Schematic of the human circulatory system.

When I was writing my blog about flow through blood vessels I became mindful that you can you can describe the entire cardiovascular system as a piping system. There is conservation of mass throughout the system (unless you are injured and bleeding). There are no sharp-edged inlets and exits or abrupt turns in the cardiovascular system so you have minimal head loss due to loss coefficients. This minimizes the required pumping power of the heart. There are changes in blood vessel diameter as you move from arteries to arterioles to capillaries, but this is a gradual change to prevent the occurrence of turbulent flow and to minimize the head loss. Blood pressure is at a maximum right after the left ventricle pumps and before the right atrium receives blood. This is due to the fact that this is an increase in mass of blood in the vessel system that is absent in the heart. The flexibility of the vessel walls expands slightly and causes an increase in the blood pressure.