How can you trace the flow of a drop of blood through the circulatory system?

Deoxygenated blood from the body enters the right atrium. It flows through the tricuspid valve into the right ventricle. Contraction of the ventricle then closes the tricuspid valve and forces open the pulmonary valve. Blood flows into the pulmonary artery. This branches immediately, carrying blood to the right and left lungs. Here the blood gives up carbon dioxide and takes on a fresh supply of oxygen. The capillary beds of the lungs are drained by venules that are the tributaries of the pulmonary veins. Four pulmonary veins, two draining each lung, carry oxygenated blood to the left atrium of the heart

From the left atrium, Blood flows through the mitral valve into the left ventricle. Contraction of the ventricle closes the mitral valve and opens the aortic valve at the entrance to the aorta. The first branches from the aorta occur just beyond the aortic valve still within the heart. Two openings lead to the right and left coronary arteries, which supply blood to the heart itself.