The Blood Vessel forms an essential part of the blood circulatory system. This helps in transporting bloods to several parts of the body. The blood vessels are available in three essential types – the arteries, the heart and the capillaries. In this way there is a vital exchange of chemicals and water substances taking place between the tissues and the blood. The veins too have an important role to play here. They collect blood from the capillaries and bring them back to the heart.When talking about the anatomy of the Blood Vessel you will come to know that they appear in three different structures – the Tunica Intima, the Tunica Media and the Tunica Adventitia.