Heart
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The Heart |
| The heart is a hollow muscular organ that receives
and distributes blood. The heart is one point in the body
that collects the blood and pumps it out into the
circulatory system. The circulatory system is a closed
system, that continually allows blood to travel a
circulatory path through the heart, into the arteries,
then to the capillaries, into the veins, and then back to
the heart. The blood carries nutrients broken down by the
intestines to give the body it's energy and the oxygen
every cell must have to live. The blood also carries away
the used air to the lungs so the "bad air" can
be exchanged with "good air" which is full of
oxygen. Blood also carries the used water to the kidneys
where it is cleaned. The clean blood is recirculated
through the body, while the waste water is sent from the
kidneys down to the bladder where it is removed through
the body as urine. The heart is about the size of your closed fist. Look at the size of your fist, then imaging the size of an adult's fist. Now you can see why little kids hearts are smaller, and adults have bigger hearts. The heart receives the blood back from the body into the right atrium. At the bottom of the right atrium is a valve that only lets the blood flow down. The blood then goes into the right venticle , which pushes the blood out through a big artery into the lungs. While the blood is in the lungs it goes through the exchange process of removing the used air and getting good air. Then the blood is pumped back into the heart through the left atrium, where it goes through another one way valve to the left ventricle. The left ventricle is the strongest part of the heart because it has to push the blood out through a big vein and it has to push it hard enough that it can go all the way down to your toes! Then the process starts all over again. Your heart beats an average of 100-120 times a minute. Imagine that's 6000 times an hour or 144,000 times a day! Your heart slows down when you rest and speeds up when you run and play. Put your hand on your chest and feel your heart beat. Every time you feel it beat you can imagine that the blood is being pushed around and doing its job. |
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This page lasted edited on 03/31/98