ANATOMY

Detailed explanation-1: -Oxygen-rich blood flows from the lungs back into the left atrium (LA), or the left upper chamber of the heart, through four pulmonary veins. Oxygen-rich blood then flows through the mitral valve (MV) into the left ventricle (LV), or the left lower chamber.

Detailed explanation-2: -Left atrium: one of the four chambers of the heart. The left atrium receives blood full of oxygen from the lungs and then empties the blood into the left ventricle.

Detailed explanation-3: -Blood flows from the right atrium into the right ventricle through the bicuspid valve. From the left ventricle, blood is pumped into the aorta, through the aortic semilunar valve.

Detailed explanation-4: -The mitral valve separates the left ventricle from the left atrium. Blood travels through the bicuspid valve to the left atrium.

Detailed explanation-5: -When the ventricular walls contract (specifically, the walls of the left ventricle), the bicuspid/mitral valve closes to prevent blood from flowing into the left ventricle from the left atrium, when the left ventricle relaxes, the bicuspid valve opens to allow blood to flow from the left atrium into the left ventricle.