Ed Golson Outdoor Education

Circulatory system

The circulatory system deals with the transportation of blood through the human body.  In an average human there are about 4-5 liters of blood.  During this process oxygen and nutrients are carried to the cells through the body and waste materials are taken away from them.  This system also moves hormones and antibodies through the body. 

There are several organs that make up the circulatory system. The heart is the organ that gets the whole process started.  The heart, which is about the size of your clenched fist, is made up of two pumps.  Each pump is divided into two chambers, the upper of which is called the atrium and the lower division is called the ventricles.  The function of the atrium is to receive the blood and make sure it flows in only one direction, and the ventricles purpose is to squeeze the blood away from the heart. Once the blood leaves your heart, it travels through a system of veins and arteries.  Veins and arteries are small tube-like tissues that extend through your entire body.  Arteries carry fresh blood away from the heart while veins carry used blood toward the heart. Veins and capillaries often separate off into smaller tubes called capillaries. Capillaries are very small blood vessels that get blood to and from individual cells.

Well you know what all these parts do; now how does this make a system?  Your heart acts as a double pump, one side is low in oxygen and the other side is rich in oxygen.  The side that is low in oxygen pumps blood through the arteries to the lungs where it receives oxygen. Then the blood goes through the veins and back to the other side of the heart.  The oxygen rich blood that was brought to the heart then gets pumped through the arteries, to the capillaries where the gas exchange occurs, and then it goes back to the veins and up to the heart where the whole process begins again!

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