The Heart

Essay by PaperNerd ContributorCollege, Undergraduate September 2001

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The heart is often associated with our emotions. The symbol of the heart is to show love. Once you know about this amazing organ you will realize why it symbolizes love, and be amazed with what it can do and is capable of.

The heart is often described as the human pump, this organ circulates blood throughout the body. This hollow muscular organ that contracts and squirts blood into the blood vessels, is about the size of a fist, and is situated in the chest cavity behind the sternum. The heart is the only organ that you can feel working.

Blood is the river of life, it gives essential supplies to every cell in your body, keeping things working and keeping you alive. Blood is also the universal garbage collector, which means that blood unloads and loads supplies into small vessels, and distributes fresh oxygen to every cell.

There is one and a half gallons of blood contained in each human body.

The length of blood vessels in miles, if they are placed end to end, is one hundred thousand miles. The speed of blood in the large vessels is one mile per hour, and in the capillaries it is one thousandth of that speed. It takes one minute for the relaxed heart muscle to transport blood around the systematic circuit. For a hard working heart to do the same job, it only takes ten seconds.

The heart walls are made out of special heart muscle called the cardiac muscle, and this is responsible for the hearts ability to contract and pump blood. The heart beats 100 000 times per day, it pumps 1/15 pints of blood. The pacemaker is a bundle of nerve cells that co "“ordinates the heartbeat and listens for messages from the body. The heart has two sides, the right and the left. These two sides have two chambers, the upper chamber is called the aorta, and the lower chambers are called the ventricles. In the lungs is where hemoglobin is filled with oxygen. The cardiac cycle comprises two circulations, once on the left side and once on the right. The cardiac cycles steps are first the blood flows into the ventricles, the ventricles then contract and blood flows into the arteries, then seventy percent of the blood flows into the ventricles from the veins and the atria. The purpose of the capillaries is to drain blood into the small veins. Arteries can change the size of capillaries to stop the blood flow or to slow it down.

The right side of the heart is the weaker side so it doesn't have as hard of a job to do. This side collects the blue colored blood. The time needed to get around the whole circuit is one minute. It pumps the blood to the lungs there the lungs discourge carbon dioxide and take fresh oxygen.

The heart is an amazing organ, it is self-regulating, self-repairing and also self powerful all in one. It is also symbolized as many things such as courage friendship and love. This is by far a very busy organ and also very amazing.