The heart of a lizard has three chambers: two atria and a single ventricle. The lizard's heart, therefore, mixes oxygenated and deoxygenated blood indiscriminately, and have a pair of aortas to distribute blood more efficiently. The two atria can funnel blood either to the lungs or the limbs and body, allowing the effective processing of deoxygenated blood and more precise thermoregulation.