The Journey of Blood Through the Heart

Study Notes

You enter the heart through the superior or inferior vena cava, the largest veins in the body, and flow into the right atrium.
The right atrium contraction sends you down into the right ventricle, giving you less than half a second to admire the scenery.
You pass through the tricuspid valve, a one-way door that prevents backflow, to enter the right ventricle.
The ventricle contraction sends you upward through the pulmonary valve and into the pulmonary artery, which sends blood toward the lungs.
The pulmonary artery splits into many smaller tubes, eventually leading to the alveoli, the tiniest tubes in the lungs, where oxygen is loaded into red blood cells and carbon dioxide is removed.
You flow back to the heart through the pulmonary veins, which dump into the left atrium.
The left atrium contraction sends you down through the mitral valve and into the left ventricle.
From the left ventricle, the ventricular contraction sends you upward into the aorta, a large tube that branches into smaller tubes to distribute oxygenated blood throughout the body.
The oxygenated blood flows through a network of tiny blood vessels called capillaries, which connect tiny artery branches to small veins, delivering oxygen to cells and transforming oxygenated to deoxygenated blood.
The deoxygenated blood travels back to the heart, and the cycle starts again, taking approximately 30 seconds to complete.