Steps of the Heart:

From the Cranial or Caudal Vena Cava

to the Right Atrium

through the Tricuspid/ Right Atrio-Ventricular Valve

to the Right Ventricle

through the Pulmonary/ Right Semi-Lunar Valve

to the Pulmonary Artery (the only artery carrying de-oxygenated blood)

to the Right and Left Lungs (artery to arterioles to capillaries to venules to vein)

to the Pulmonary Vein (the only vein carrying oxygenated blood)

to the Left Atrium

through the Bicuspid/Mitral/Left Atrio-Ventricular Valve

to the Left Ventricle

through the Aortic/Right Semi-Lunar Valve

to the Aorta