Skip to main content
. 2021 Nov 23;17:739–769. doi: 10.2147/VHRM.S328096

Figure 1.

Figure 1

Parts of the cardiovascular system and their functions. The upper two (or atria) chambers operate mainly as chambers for collection, while the lower two chambers (ventricles) are considerably stronger and are used to provide blood. The right atrium and ventricle are responsible for collecting blood from the body and pumping it to the lungs. Blood is collected from the lungs and pumped throughout the body by the left atrium and ventricle. The heart has a one-way flow of blood, which is maintained by a series of four valves. The tricuspid and bicuspid atrioventricular valves allow blood to pass only from the atria to the ventricles. Only blood from the ventricles can flow out of the heart through the semilunar valves (pulmonary and semilunar).3 In other side, it should be noted that in addition to pumping oxygen-rich blood into body tissues, the blood also circulates many other important substances for oxygen exchange for carbon dioxide. As example, digestive nutrients are collected from the small intestine and pumped into all the cells in the body by the circulatory system. The circulatory system transports waste materials from cells into the kidneys, extracted and transmitted into the bladder. An important function of the heart in this matter is the pumping of interstitial blood fluid into the extracellular space. The circulatory system then returns excess interstitial fluid through the lymphatic system.3 The heart is a rhythmic electromechanical pump as its performance is dependent on the formation and propagation of action potentials, followed by relaxation and a period of refractoriness before the next impulse is created. The inward of Na+ current and outward of K+ current carrying ion channels are sequentially activated and inactivated in myocardial action potentials. Due to variances in Na+, Ca2+, and K+ channel expression in different parts of the heart, action potential waveforms are diverse, and these differences contribute to the normal, unidirectional transmission of activity and the formation of normal cardiac rhythms.154