Circulatory System:
The Northern Fence lizard has a three-chambered heart. The heart consists of two aortas, two atria and a ventricle. Their heart allows for the blood to be redirected to the body or the lungs so that there is better thermoregulation. They also have a muscular septum that divides the ventricle. When the ventricle contracts, the septum opens and the ventricle divides into two chambers preventing the oxygenated blood and deoxygenated blood from mixing. The left side of the ventricle pumps oxygenated blood from the left atrium to the body. The right side of the ventricle pumps deoxygenated blood from the right atrium to the lungs.