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Explain the cardiac cycle in detail. |
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Answer» The cardiac cycle is the series of electrical impulses and muscle contractions that pressurizes different chambers of the heart, causing blood to flood in one direction. The cardiac cycle varies in different organisms, due to changes in the structure of the heart. Some organisms have a three-chambered heart, which consists of the sinus venosus, atrium, and ventricle. Most tetrapods have developed a more efficient heart, which can supply a greater pressure of blood to the organisms. The “four-chambered heart”, is actually just a modification of the three chambered heart. The sinus venosus is reduced to the sinoatrial node, located on the right atrium. The atrium and ventricles are divided in the four-chambered heart, allowing a separate pathway to be established to the lungs, allowing for greater oxygenation of the blood. The separate circulations pathways are known as pulmonary (lungs) and systemic (body) circulation. |
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