How the human body is truly remarkable
Have you ever asked yourself, how can the heart pump blood throughout our body, especially when fighting against such a powerful force like gravity? If you have you’re not alone. The heart isn’t strong enough to perform this task on its own, but with the reliance of small valves found within veins and muscle contractions it aids in the completion of this task. Muscle contractions occur from
skeletal muscles when a person is walking or moving about. The valves close when blood begins to flow in one direction, this makes sure that the blood can only flow back to our heart, meaning the blood can travel up the legs.
Blood gets moving
Blood is forced to move when “you squeeze your leg muscles to walk, stand, kick, and move about, the muscles squeeze the veins…” thus enabling the circulation of blood to take place. Due to valves in the heart, “ the blood can only move in one direction as it gets squeezed along. So it is a combination of blood pressure from the heart’s pumping action, the valves, and muscle movement that gets the blood up the legs against gravity.”
Caution: Malfunctioning Veins
“If the valves malfunction, then the blood falls back down to some extent after every muscle contraction and begins to pool in the veins. This causes the veins to swell with blood, which can be painful and unsightly, and is known as varicose veins.” A study done based on astronauts in NASA shows how the cardiovascular system can get lazy when in space. Every time we stand up, gravity is able to pull blood into parts of our body that are below our heart. However, in space there is no gravity, hence blood can’t be pulled into different parts of the body that are below the heart. “Instead, blood goes to the chest and head, causing astronauts to have puffy faces and bulging blood vessels in their necks. And appearance isn’t the only ugly side effect. The lack of blood flowing to and from the brain can cause astronauts to feel dizzy and sometimes even faint when they return to Earth’s gravity.” That is why the International Space Station has conducted an experiment on how “ long-duration exposure to microgravity affects crew members’ heart functions, blood pressure and blood vessels that supply the brain.” Varicose veins occur when superficial veins become dilated and irregular. This happens due to abnormally high pressures from deep veins. Some less invasive treatments to fix this dilemma can be elastic support stockings which “compress the varicose veins and reduce the flow down them improving the circulation (NB do not use stockings if you have bad arterial disease in the legs). Elevation of the legs whenever possible and avoiding long
periods of standing will also help relieve the symptoms of varicose veins. Being overweight raises the pressure in the leg veins so losing weight can also be very beneficial.” On the other hand, if these treatments don’t work procedures done on the veins can help significantly, particularly when the problem comes from superficial veins.
As one can tell the human body goes through a lot to get blood flowing throughout its entirety. Despite it seeming as if gravity would slow down this process it actually helps speed it up. Without the effects of gravity on our bodies, it’s easy to see the catastrophic effects it can have. Although our heart doesn’t do all the work, it’s essential in keeping us alive and keeping our blood pumping. It’s clear to see the human body is truly extraordinary, this is just one example of what the body is capable of.