1. Arteries - These vessels carry oxygen-rich blood away from the heart to the tissues. They have thick, muscular walls to withstand high pressure. 2. Veins - Veins return oxygen-depleted blood back to the heart. They have thinner walls and often contain valves to prevent backflow. 3. Capillaries - These are the smallest blood vessels where the exchange of gases, nutrients, and waste products occurs between blood and tissues.
