AP BIOLOGY

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.

Detailed explanation-2: -Pulmonary veins are blood vessels that carry oxygen-rich blood from your lungs to your heart. Your pulmonary veins are part of your body’s pulmonary circuit.

Detailed explanation-3: -In the lungs, the blood receives oxygen then leaves through the pulmonary veins. It returns to the heart and enters the left atrium. From there, blood is forced through the mitral valve into the left ventricle. This is the muscular pump that sends blood out to the rest of the body.

Detailed explanation-4: -Both the superior vena cava and inferior vena cava empty blood into the right atrium. Blood flows through the tricuspid valve into the right ventricle. It then flows through the pulmonic valve into the pulmonary artery before being delivered to the lungs.