The human circulatory system is based upon two main components: the vessels and the heart. Both components circulate blood and provide oxygen, hormones, body temperature management, chemicals, gases, lymph and the necessary nutrients to the bodies cells. They also remove waste and carbon dioxide products from within the body.
The human heart has four chambers which are the left ventricle, right ventricle, left atrium and right atrium. De-oxygenated blood returns to the right sided chambers of the heart and passes through to be re-oxygenated to once again flow through the bodies circulatory system. Blood which returns to the heart which still contains oxygen delivers itself the the left atrium, usually from the lungs and waits there until it is time to be cleansed and re-circulated.
Once the blood has past through the heart, it then flows through the arteries, capillaries and arterioles completing the path of the circulatory system as it returns back to the heart. The arteries of the circulatory system (not including the umbilical and pulmonary arteries) carry the blood flow away from the chambers of the heart to the arterioles. The blood then flows from the arterioles to the capillaries which are the smallest blood vessels of the human body, before passing through the veins and venules and returning back to the heart for another cycle.
The human circulatory system does not only rely on internal sources of the body. As you breath in fresh air, the oxygen received within the body is directed directly to the circulatory system and provides a dissolved carbon dioxide in the lungs and oxygen to the bodies cells.
Every organ and system within the human body is connected to the circulatory system. The human body has 12 very important systems. The Circulatory system aids the digestive system, endocrine system, respiratory system, muscular system, skeletal system, immune system, excretory system, urinary system, reproductive system, nervous system and digestive system which all require nutrients, oxygen, cleansing and more.