Medical Questions » Heart Questions » Question No. 484
| Question: | I need to know how the heart works for a school project. |
| Answer: | The heart is a hollow ball of muscle about the same size as your fist, and it acts as a very efficient pump. It is situated high in the chest behind the breast bone, and one corner extends out towards the left nipple.
The hollow heart is divided into four chambers by relatively thin walls made of muscle and fibrous tissue. The upper right chamber (right atrium) of the heart receives the blood returning through the veins from all parts of the body. With a gentle squeeze, it pushes the blood through a valve into the lower right chamber A split second later, the lower right chamber (right ventricle) contracts quite forcibly to push the blood into the lungs. There it loses the carbon dioxide it has picked up in the body and exchanges it for oxygen.
From the lungs, the blood flows into the upper left chamber of the heart (left atrium). This acts in the same way, and simultaneously with, the right atrium, and pushes the blood into the final chamber, the left lower one (left ventricle). This is the most powerful and important chamber of the four as it is responsible for pumping the blood out of the heart and around the body. The flow of blood to the head, ail organs and down to the toes is caused by the contraction of the left ventricle.
After passing through microscopic capillaries, the blood moves back through the veins to the heart' s right atrium, completing the cycle.
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