The circulatory system is a complex arrangement of tubes that transport blood as well as waste products throughout the entire body. The system depends on a complex series of events. We however are going to look at a simple overview of this system.
The heart is the main pump. The heart is divided into four chambers. The top two chambers are the atriums and the bottom two chambers are the ventricles. The atriums both contract at the same time as do the two ventricles. Blood enters the heart via the superior and the inferior vena cava. These are the two largest veins in the body. The right atrium receives the blood first. The right atrium contracts and forces the blood into the right ventricle.
When the right ventricle contracts the blood is pumped into both lungs via the pulmonary artery. This portion of the circulatory system is sometimes referred to as pulmonary circulation or lesser circulation. The pulmonary artery is the only artery in the body that carries deoxygenated blood. Blood is returned from the lungs via the pulmonary veins.
These are the only veins in the body that carry oxygenated blood. The oxygenated blood is returned to the left atrium. When the atrium contracts the blood is forced into the left ventricle. The left ventricle is the strongest and most muscular portion of a healthy heart.
This is due to the fact that the left ventricle works the hardest. It must force blood throughout the body. When the left ventricle contracts, blood is forced into the aorta. The aorta is the main artery leaving the heart.
The oxygenated blood is now forced throughout the body through a series of arteries that gradually become smaller and smaller. Blood flows from arteries into arterioles. From arterioles into capillaries. At this point, the blood is able to make close contact with individual cells. Here is where waste products are picked up and oxygen is delivered.
The blood now starts its return trip to the heart. From the capillaries the blood flows into venules. These are very small veins. (About the same size as capillaries) From the venules the blood is forced into veins These veins all return blood either into the superior or the inferior vena cava. As stated earlier, the inferior and the superior vena cava return the deoxygenated blood to the right atrium of the heart.
Always bear in mind that although the heart is the main pump of the circulatory system, there is a secondary sort of minor pump. As we move about our daily lives our muscles help circulate blood. As we move our muscles contract and squeeze against our veins. Our veins have tiny valves that allow blood to only flow towards the heart. These valves and the contraction of muscles assist the heart in its efforts to circulate blood throughout the body.
As the deoxygenated blood makes its way back to the heart it is cleaned of waste products that occur as a result of cellular activity. This is accomplished via the liver and the kidneys. Deoxygenated blood is heavy with carbon dioxide. ( CO2) Carbon dioxide is vented by the body with every breath we exhale. It is oxygenated with every breath we inhale.
Next time you take a breath or feel your heartbeat you will now understand a portion of the miracle that takes place within our bodies.