Amazing Heart Facts
Let's get straight to the heart of the
matter--the heart's job is to move blood.
Day and night, the muscles of your heart
contract and relax to pump blood throughout your
body. When blood returns to the heart, it
follows a complicated pathway. If you were in
the bloodstream, you would follow the steps
below one by one.
1.Oxygen-poor blood (shown in blue) flows from
the body into the right atrium.
2.Blood flows through the right atrium into the
3.The right ventricle pumps the blood to the
lungs, where the blood releases waste gases and
picks up oxygen.
4.The newly oxygen-rich blood (shown in red)
returns to the heart and enters the left atrium.
5.Blood flows through the left atrium into the
6.The left ventricle pumps the oxygen-rich blood
to all parts of the body.
Do right and left seem backward? That's because
you're looking at an illustration of somebody
else's heart. To think about how your own heart
works, imagine wearing this illustration on your
Sure, you know how to steal hearts, win hearts,
and break hearts. But how much do you really
know about your heart and how it works? Read on
to your heart's content!
Put your hand on your heart. Did you place your
hand on the left side of your chest? Many people
do, but the heart is actually located almost in
the center of the chest, between the lungs. It's
tipped slightly so that a part of it sticks out
and taps against the left side of the chest,
which is what makes it seem as though it is
Hold out your hand and make a fist. If you're a
kid, your heart is about the same size as your
fist, and if you're an adult, it's about the
same size as two fists.
Your heart beats about 100,000 times in one day
and about 35 million times in a year. During an
average lifetime, the human heart will beat more
than 2.5 billion times.
Give a tennis ball a good, hard squeeze. You're
using about the same amount of force your heart
uses to pump blood out to the body. Even at
rest, the muscles of the heart work hard--twice
as hard as the leg muscles of a person
Feel your pulse by placing two fingers at pulse
points on your neck or wrists. The pulse you
feel is blood stopping and starting as it moves
through your arteries. As a kid, your resting
pulse might range from 90 to 120 beats per
minute. As an adult, your pulse rate slows to an
average of 72 beats per minute.
The aorta, the largest artery in the body, is
almost the diameter of a garden hose.
Capillaries, on the other hand, are so small
that it takes ten of them to equal the thickness
of a human hair.
Your body has about 5.6 liters (6 quarts) of
blood. This 5.6 liters of blood circulates
through the body three times every minute. In
one day, the blood travels a total of 19,000 km
(12,000 miles)-- that's four times the distance
across the US from coast to coast.
The heart pumps about 1 million barrels of blood
during an average lifetime--that's enough to
fill more than 3 super tankers.
lub-DUB, lub-DUB, lub-DUB. Sound familiar? If
you listen to your heart beat, you'll hear two
sounds. These "lub" and "DUB" sounds are made bythe heart valves as they open and close.