Blood lines refer to the pathways of blood in the human body. The term is composed of five words: Aortae (6 letters), ARTERIES (8 letters), Aortas (6 letters), Veins (5 letters), and Vessels (7 letters). Aortae are the two main ARTERIES that carry oxygenated blood away from the heart. ARTERIES are the vessels that carry oxygenated blood away from the heart to the rest of the body. Aortas are the largest artery in the body, carrying oxygenated blood from the heart to the rest of the body. Veins are the vessels that carry deoxygenated blood back to the heart. Vessels are the general term for any type of blood vessel, including ARTERIES, veins, and capillaries. Together, these five words form the term 'blood lines, ' which refers to the pathways of blood in the human body.