Physics is known to be a natural science. It primarily involves the study of matter and the movement of matter through time and space, along with related concepts such as force and energy. Does the circulatory system apply physical concepts as blood circulates through the entire system? The main goal of the circulatory system is to transport blood to all necessary parts of the body. The blood actually carries nutrients and oxygen to these parts of the body and wastes are transported from these parts of the body to the organs that expel them from the body. The heart is the nerve center of the circulatory system. This is because it is the blood-pumping organ that transports both nutrients and waste to the appropriate parts of the body. The flow of fluids in the circulatory system obeys the law of mass flow. The equation for the mass flow law is given by: Q = P / R where Q is the flow rate, R is the resistance, and P is the pressure gradient. These fluids, like blood, flow along pressure gradients. There is a physical relationship between blood vessel radius and fluid flow resistance. According to Poiseuille's equation, the relationship between resistance and radius is inversely proportional. This means that a small change in radius would result in large changes in flow resistance. The body uses this concept to control the flow of fluids in the circulatory system through vasodilation and vasoconstriction. In addition to the two laws above, total blood flow also follows the principle of the law of conservation of mass. This is true regarding fluid flow in the circulatory system; there must be equality of flow through each segment of the entire circulation…half of the paper…has the function of carrying deoxygenated blood from the tissues to the heart and oxygenated blood from the heart to the tissues. The pulmonary system, on the other hand, transports deoxygenated blood from the heart to the lungs and oxygenated blood from the lungs to the heart. In summary, the physics of the circulatory system is a broad topic that can take days to explain. This is evident since the circulatory system obeys physical laws such as Poiseuille's equation, mass flow, Bernoulli's principle, and the principle of the law of conservation of mass. Diffusion, serial and parallel arrangement of blood flow, gravitational force, and single or double circuit are all physical concepts applied to the circulatory system. The circulatory system works under the assumption that the blood is incompressible, that the blood vessels are rigid, and that there is no leakage or transfusion of blood into the system.