The Circulatory System MIT Self Work Made by: Vaisakh Murali Group 4B 2018 Introduction The circulatory system is centred on the Heart, a muscular organ that rhythmically pumps blood around a complex network of blood vessels extending to every part of the body. Blood carries the oxygen and nutrients needed to fuel the activities of the body’s tissues and organs, and it plays a vital role in removing the body’s waste products. An average-sized adult carries about 5 litres of blood. Parts of the System All the output of blood from the left side of the heart goes into the aorta, the body’s largest artery. Other arteries branch from the aorta to supply blood to the head, limbs, and internal organs. The blood is drained from all these parts by veins into two large vessels, the inferior and superior venae cava, which deliver the blood back to the right side of the heart. Heart The heart contracts tirelessly – more than 2.5 billion times ove