The human circulatory system functions to transport blood and oxygen from the lungs to the various tissues of the body. The organs involved in the circulation of blood in the body form the circulatory system. Heart and blood vessels are the most important parts of our circulatory system. Heart is a muscular organ and it weighs about 300 Grams. It works like a pump and sends blood through a network of blood vessels known as arteries to different parts of the body. The blood returns to the heart for purification through veins. In this way, blood reaches every cell in the body to provide it with food and oxygen and to carry way waste products.
Our circulatory system is a fine network of arteries, arterioles, capillaries and veins.
Arteries and Veins:
Thecoronary arteries arise at the point of maximum blood pressure in the circulatory system. An artery is a large vessel that carries blood from the heart to the different parts of the body. It branches into the smaller arterioles which further divide into very small vessels called capillaries. Capillaries carry blood to the cells. Capillaries change to venal capillaries, venules and finally veins. Veins carry the blood back to the heart. Scientists guess there are about 100,000 kms of blood vessels in our bodies.