Nina studies an artificial heart model. The model has tubes that supply an electric current to the model. Nina switches on the current that provides an impulse to the heart. She observes that the heart contracts and relaxes. Compare this model with that of a human heart, and place the steps describing how blood flows through the human heart in order. signal transferred to the ventricles
the atria contract
electrical signal travels toward the heart
the ventricles contract
signal by the nodes in the atrium
signal received by the atrioventricular node