How the Cardiovascular System Works
As you inhale, air moves down the trachea into the bronchi, bronchioles and finally into the 600 million air sacs — called alveoli — in the lungs. Oxygen passes from the alveoli into the tiny blood cells called capillaries that cover them. The oxygen-rich blood from the lungs is transported to the left altrium of the heart. The heart contracts moving blood into the left ventricle. The next contraction pumps the blood into the aorta. From the aorta, oxygen-rich blood pumps into the body’s arteries, which branch into smaller arterioles, and then to the capillaries, which deliver oxygen and nutrients to the body’s cells and pick up carbon dioxide and other cellular waste. Capillaries, venules and veins return the oxygen-depleted blood to the heart, where it collects in the right ventricle and then to the lungs. The capillaries transfer carbon dioxide and cellular waste into the alveoli where they exit the body through the bronchioles, bronchi and trachea.
Fun Facts About The Heart
- The heart beats over 100,000 times every day
- During an average lifetime, the heart pumps nearly 1.5 million barrels of blood
- Your heart creates enough energy every day to drive a truck 20 miles
- It takes less than 60 seconds to pump blood to every cell in the body