First, the blood moves from the right atrium to the right ventricle through the tricuspid valve. The ventricle then pumps the blood to the pulmonary arteries to travel through to the lungs through the pulmonary valve. The blood goes from arteries to arterioles, and finally to capillaries on the alveoli in the lungs, where through the process of diffusion, gas exchange happens, and the blood becomes oxygenated, and gets rid of carbon dioxide. Then, the blood travels back through the heart through the pulmonary veins back to the heart. There, the blood enters the left atrium. From there, it enters the left ventricle through the mitral valve. The left ventricle then pumps the blood throughout the body. The left ventricle pumps the blood through
