The heart is an essential body part responsible for pumping blood to all body parts through the circulatory system, providing nutrients and oxygen to the tissues while excreting carbon dioxide. The heart comprises several components, such as four chambers, heart layers, arteries, veins, and valves, to enhance the proper flow of blood.
The heart is a complex structure due to its pumping mechanism that provides blood distribution to body parts and receiving it back to the heart. The heart is also responsible for thermoregulation, maintenance of fluid balances in the body, and prevents blood loss and infections in the body. The heart walls comprise three layers; namely, a thin outer layer is known as epicardium, a thin inner layer referred to as endocardium, and a thick middle layer composed of cardiac muscle fibers, the myocardium.
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The heart comprises of four chambers, two ventricles, and two atria. The two atria chambers are positioned on the upper part of the heart featuring atrioventricular valves separating them. Atrioventricular valves comprise of mitral and tricuspid valves to the right and left, respectively. Alternatively, ventricles are located on the lower part of the heart and are responsible for pumping blood to body parts. Like the atria chambers, semilunar valves provide a separation between the two chambers, aortic and pulmonary valves.
Since the body tissues require a constant blood supply to function, a continuous flow of blood is enhanced by the blood vessels, including veins, arteries, and capillaries. These blood vessels are characterized according to their functions. Coronary veins are blood vessels responsible for carrying oxygen-free blood to the heart from body parts, excluding pulmonary veins that convey blood enriched with oxygen to the heart from the lungs. Coronary veins have valves, which enhances unidirectional blood flow to the heart. The blood in veins flow at a lower pressure; hence their walls are thin, providing a wide lumen.
On the other hand, arteries carry oxygen-rich blood to all body parts from the heart, except for the pulmonary artery that allows oxygen-free blood flow to the lungs ( Juan et al., 2019 ). The arteries' pressure is high; hence their walls are thick to withstand the high pressure, thereby providing a narrow lumen. Unlike veins, coronary arteries do not have valves.
Capillaries are the smallest blood vessels, one cell thick, joining venules and arterioles. They transfer nutrients and oxygen from arteries to all body tissues, while collecting waste products to veins. Capillaries are very numerous as compared to veins and arteries since they provide the respiration sites. Similar to arteries, capillaries do not have valves.
The cardiac cycle promotes blood distribution through the blood vessels to all body parts. Blood circulation starts once the right atrium receives deoxygenated blood, enters the right ventricle, and lungs through the pulmonary artery. In the lungs, carbon dioxide is excreted and blood refilled with oxygen, after which it flows to the heart into the left atrium and ventricle for redistribution. From there, any disorder in the heart can be easily monitored, affecting the heart's performance. For instance, tracking the heartbeat helps detect heart illnesses since the heartbeat is linked with reloading oxygen, which comprises two phases.
While systole is associated with the closure of mitral and tricuspid values for a short period, diastole occurs when the pulmonary and aortic valves close for a more extended period. Hence, the reference for determining blood pressure is the relationship between diastole and systole phases. Besides, determining the number of heartbeat per minute is another way of predicting if the heart's performance is normal or abnormal.
Based on the case study, atherosclerosis is a condition caused by the progressive accumulation of fats on the coronary arteries walls, causing narrowing the blood vessel ( Taleb, 2016 ). The accumulation of plaque eventually results in the hardening of the arteries, thereby becoming inelastic and inflexible. The accumulated fat on the coronary artery walls may rupture, and the platelets present in the blood form a blood clot as their role. The clot formed further leads to the blockage of the artery, where the total blockage blood is ultimately restricted to flow. Consequently, blood flow to a particular heart muscle is halted, thereby cutting down the nutrients and oxygen supply, leading to a heart attack. Heart attack stops the cardiovascular system, thereby creating a disconnect between other organ systems, leading to death.
Different animals employ different circulatory systems, namely; closed and open circulatory systems. All invertebrates use the open circulatory system, involving the pumping of blood by the heart to the body cavity; hence all tissues are bounded by blood ( Firdauzi & Masrifah, n.d ). On the other hand, a closed circulatory system involves pumping blood by the heart through blood vessels. Thus, no blood in cavities, for instance, vertebrates' circulatory system. In the closed circulatory system, blood circulation is fast; therefore, nutrients, oxygen, and waste products are transported faster than in an open circulatory system. Also, in a closed circulatory system, the distinction between tissue fluid and blood is easy than in a free circulatory system.
In conclusion, the cardiovascular system is an organ system composed of different parts working dependently. When one component fails to function, the whole system is paralyzed, causing failure to other organ systems. For instance, the cardiovascular system is linked with other organ systems such as the respiratory system and excretory system; hence its failure results in the disruption of the whole organizational unit. Therefore, all organ system works together to facilitate the functioning of essential processes, which sustains life.
References
Firdauzi, A. A. M., & Masrifah, S. CIRCULATORY SYSTEM.
Juan, A., Ince, L. M., Pick, R., Chen, C. S., Molica, F., Zuchtriegel, G. & Pelli, G. (2019). Artery-associated sympathetic innervation drives rhythmic vascular inflammation of arteries and veins. Circulation , 140 (13), 1100-1114.
Taleb, S. (2016). Inflammation in atherosclerosis. Archives of cardiovascular diseases , 109 (12), 708-715.
