Physics is known to be a natural science. It primarily involves the study of matter and its movement through time and space, as well as related concepts such as force and energy. Does the circulatory system apply physics concepts as blood circulates throughout the system? The main purpose of the circulatory system is to transport blood to all the necessary parts of the body. This is because the blood carries nutrients and oxygen to these parts of the body and wastes them to the organs that excrete them out of the body. The heart is the nerve center of the circulatory system. Indeed, it is this organ that pumps blood 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 overall flow. The equation of the global flow law is given by: Q = P / R where Q is the flow, R the resistance and P the pressure gradient. These fluids, like blood, flow along pressure gradients. There is a physical relationship between the radius of blood vessels and the resistance to fluid flow. 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 above two laws, total blood flow also follows the principle of the law of conservation of mass. This is true for the fluid that circulates in the circulatory system; there must be equality of flow through each segment of the entire circulation...... middle of paper ......function to transport deoxygenated blood from the tissues to the heart and oxygenated blood from the heart to the fabrics. 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 vast subject that can take days to explain. This is evident since the circulatory system obeys physical laws such as the Poiseuille equation, mass flow, Bernoulli's principle and the principle of the law of conservation of mass. Diffusion, series and parallel arrangement of blood flow, gravitational force and single or double circuits are all physical concepts applied to the circulatory system. The circulatory system assumes that blood is incompressible, the vessels are rigid, and there is no loss or transfusion of blood in the system..