How to Identify the Parts of the Cardiovascular System
The cardiovascular system is one of the most important in the entire body. It primarily includes the heart, the blood and the network of blood vessels that allow for circulation throughout the body. Through the cardiovascular system, oxygen and nutrients reach all cells in the body, and cells dispose of their metabolic wastes. The several organs of the cardiovascular system each contain individual parts that can be distinguished and identified.
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Instructions
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The Heart
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Enter the heart via the atria. The heart has two chambers called atria, which are responsible for receiving blood returning through the cardiovascular system through the veins. Blood that enters the right atrium has been depleted of oxygen from its trip through the body. The blood entering the left atrium is returning from the lungs freshly oxygenated and ready for recirculation.
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Pump with the ventricles. The most noticeable function of the heart is its pumping action. This is performed by the ventricles, which are chambers lined with strong cardiac muscles. The ventricles pump simultaneously, but the right ventricle is attached to the lungs via the pulmonary artery--it sends blood to the lungs to be enriched with oxygen. When the left ventricle pumps, it pushes blood out of the heart through the aorta and to the rest of the body.
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Keep them separated. The heart can only perform its functions as long as its four chambers remain completely separate. To make sure this is so, a thick wall of muscles sits between them, called the cardiac septum. The word "septum" comes from the Latin for a dividing wall. Where the septum divides the atria, it is called inter-atrial, and where it separates the ventricles it is called inter-ventricle.
Blood
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Deliver oxygen through red blood cells. One of the most important functions of the blood is to deliver oxygen to the body, and this is performed by the red blood cells, which give blood its distinct color. The red blood cells are only red, however, when they are carrying oxygen, which they do through a compound called hemoglobin. When hemoglobin binds with oxygen, it takes on a red tint. Red blood cells are produced mostly in the bone marrow.
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Defend the body with white blood cells. Another major function of the blood is to circulate the germ-fighting cells of the immune system. These are not literally white, but do not turn red because they do not contain hemoglobin. The official term for white blood cells is "leukocytes," of which there are five different types. All combat infection of the body in some way and increase their numbers in response to need.
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Go with the flow. The red and white blood cells wouldn't get very far if they weren't suspended in a liquid that allowed them to flow. Plasma can be separated from the other components of the blood through a centrifuge, which causes the more dense blood cells to settle to the bottom. Plasma is about 55 percent of total blood volume. Floating in the plasma are tiny blood cells called platelets. Though small, platelets are what cause blood to clot, transforming from a liquid to a solid and thus allowing wounds to heal.
Blood Vessels
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Pulse with the arteries. If you've ever taken someone's pulse, what you were using to feel the beat of her heart is an artery. These are the thick blood vessels that lead away from the heart. Arteries carry blood rich in nutrients and oxygen to the rest of the body and literally pulse with each beat of the heart. In order for the arteries to allow blood flow, they must be able to expand and contract. Serious cardiovascular disease results when the vessels become rigid or blocked with fatty tissue buildup.
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Bathe in the capillaries. As the arteries branch out from the aorta, they get smaller and smaller. Eventually, they give way to tiny blood vessels just one cell thick. These capillaries allow the blood to flow directly over the cells of the body, where nutrients and wastes can be exchanged through the cell walls.
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Re-collect with the veins. As blood washes over the cells, it is depleted of oxygen and nutrients. This spent blood collects in small vessels called veins. Because the hemoglobin of this blood is no longer bound to oxygen, it loses its red tint, which is why veins appear blue. Like a river gradually making its way to the ocean, small veins feed into larger veins, which pass the blood through the kidneys and liver, where the wastes are removed and sent to be excreted. Eventually, the veins come together in the superior vena cava, which enters the right atria so the process can begin again.
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