Your heart is the only bodily organ in a closed cardiovascular system. It tends to its life-sustaining work aided by arteries, arterioles, capillaries, venules, and veins. A miracle of high-intensity performance, the heart beats between 60 and 70 times per minute, 93,000 times per day, 655,000 times per week, 34 million times per year, and 2.4 billion times in an average lifetime. It fuels itself, paces itself, repairs itself, and alters itself in response to lifestyle and environmental changes, with no conscious effort by you. Whether you’re a sprinter or couch potato, complex nervous and hormonal regulation maintains your heart’s optimal rate and output. At any particular time, the functioning organs of your body receive a share of blood in proportion to their need, and those that are resting quietly receive theirs in metered measure.
Your red blood cells, oval shaped to maximize their transportation of oxygen, are manufactured and destroyed at an alarming rate. Approximately ten million red blood cells are produced every hour, while an equal number self-destruct. Blood cell supply variations of as little as 1 percent can shut down your normal bodily functions. The imbalance created when your blood gets so thin that oxygen transport is insufficient (anemia) or so thick that it can no longer circulate (polycythemia) represent life threatening conditions. Blood clotting is similarly complex requiring the coordinated function of at least eleven chemical factors. Blood that clots too readily or too slowly is problematical; clots that fail to dissolve can prove fatal.
These additional facts highlight your cardiovascular system’s efficiency and resiliency:
- On average, the heart pumps between 430 to 460 gallons of blood every day.
- A baby’s body holds about a quart of blood at birth while an adult stores about 1.3 gallons.
- It only takes twenty seconds for blood to completely circulate through the human body.
- One drop of blood contains ten to thirteen thousand white blood cells and five million red blood cells.
- Some sources estimate that if all of the arteries, arterioles, capillaries, venules and veins were laid end to end, they would measure somewhere between fifty thousand to one hundred thousand miles in length.
- Most blood cells are produced in the bone marrow while plasma is manufactured in the liver.
Scientists agree that the human heart is a masterpiece of mechanical, chemical, and bioelectrical design. It continues to tick away, pumping vital nutrients and oxygen to every part of the body, with no visible source of power, no cord to plug into the wall. With all our technical knowhow, even the most sophisticated artificial hearts manufactured today can’t compete with the real thing in terms of performance or longevity. As a pump, regulator, and power generator, the heart has no rivals and would win any of today’s most prestigious design competitions.