Smart Doctor on Instagram: "All 4 Heart Valves in Action 🫀 - - In this 3D animation, we go inside the left side of the human heart and follow oxygenated blood coming back from the lungs. The red blood enters the left atrium through the pulmonary veins, then passes through the mitral valve into the left ventricle. When the ventricle contracts, the aortic valve opens and the blood is powerfully ejected into the aorta, sending oxygen to the entire body. The valves act like one-way doors, making su