6. One-way blood flow through the heart

The right side sends _, and the left side sends _.

deoxygenated blood to the lung, oxygenated blood to the systemic circulation

The venae cavae _.

returns systemic blood to the right atrium

Blood passes through the right AV valve into the _.

right ventricle

Right-ventricular contraction sends blood through the _.

pulmonary valve into the pulmonary artery and to the lungs.

Oxygenated blood returns from the lungs to the _.

left atrium through the pulmonary veins

Blood passes through the left AV valve into the _.

left ventricle

Left-ventricular contraction sends blood through the _.

aortic valve into the aorta and the systemic circulation

Valves open and close because of _.

pressure differences

When a ventricle contracts, pressure closes its _ and opens the _.

AV valve, aortic or pulmonary valve

Elastic recoil of the aorta can _, but the aortic valve _.

push blood toward the heart, prevents that blood from reentering the ventricle