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. Oxygen-rich blood then flows through the mitral valve (MV) into the left ventricle (LV), or the left lower chamber.

Detailed explanation-2: -The oxygenated blood is brought back to the heart by the pulmonary veins which enter the left atrium. From the left atrium blood flows into the left ventricle. The left ventricle pumps the blood to the aorta which will distribute the oxygenated blood to all parts of the body.

Detailed explanation-3: -Right atrium: Receives blood returning to the heart from the superior and inferior vena cava; transmits blood to the right ventricle, which pumps blood to the lungs for oxygenation.

Detailed explanation-4: -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.