Cardiac function: overview of the cardiovascular system. The cardiovascular system has three components: the heart, The heart performs sensory and endocrine functions that help. The ability of cells to exchange materials with their immediate environment is an absolute requirement in life. Diffusion works well for short distance transport but for humans, diffusion cannot provide cells with all that they need as quickly as they need it since diffusion is efficient but is a slow process. Our body needs a much faster mechanism of transport. The cardiovascular system can deliver materials throughout the body faster than diffusion could because molecules in the blood move by bulk flow. The most important function of the cardiovascular system is to efficiently transport materials to and from places. blood and blood vessels. The heart is a muscular pump that drives the blood through the blood vessels. The blood is the fluid that circulates around the body carrying materials to and from the cells.