Blood vessels are an important part of the circulatory system, responsible for transporting blood throughout the body. The term 'blood vessel' can refer to a variety of different structures, including capillaries (9 letters), which are the smallest and most numerous of the vessels; arterioles (9 letters), which are small arteries; veins (4 letters), which carry deoxygenated blood back to the heart; VENA (4 letters), which is another name for veins; AORTA (5 letters), which is the largest ARTERY in the body; CAVA (4 letters), which is a large VEIN; arteriole (6 letters), which is a small ARTERY; and angio (5 letters), which is a prefix meaning 'blood vessel'. Additionally, VIAL (4 letters) is a term used to describe a small container, often used to store blood samples.