The cardiovascular system of the human body has one distinct job; that is to pump the blood to the different parts of the body.  The central organ in this
system is the heart. It is made up of cardiac tissue and its job is to pump
the blood. It first pumps the blood to the lungs to get oxygen, and then to
the various parts of the body for distribution.  The blood travels through a
series of arteries and veins.  The difference between the two is that
arteries carry oxygenated blood from the heart to the body, and the veins
return the oxygen-free blood back to the heart.  The circulatory is not
complex, but it does an imperative job for the body.