The term 'circulatory vessel' refers to the vessels that transport blood throughout the body. The two most common types of circulatory vessels are the AORTA and the ARTERY. The AORTA is the largest ARTERY in the body, and it carries oxygenated blood from the heart to the rest of the body. The ARTERY is a smaller vessel that carries oxygenated blood away from the heart to the organs and tissues. Both the AORTA and the ARTERY are essential for the proper functioning of the circulatory system.