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The heart is a muscular organ situated in the mediastinum.It consists of four chambers, four valves, two main arteries (the coronary arteries), and the conduction system. The left and right sides of the heart have different functions: the right side receives de-oxygenated blood through the superior and inferior venae cavae and pumps blood to the lungs through the pulmonary artery, and the left ...
Because the contraction starts near the base of the left ventricle and spreads toward the apex most of the longitudinal fibers of the left ventricle have shortened before the apex. The rapidly increasing pressure developed by the shortening of these fibers causes the aortic valve to open and the apex to move outward causing the PMI.
The papillary muscles are muscles located in the ventricles of the heart. They attach to the cusps of the atrioventricular valves (also known as the mitral and tricuspid valves) via the chordae tendineae and contract to prevent inversion or prolapse of these valves on systole (or ventricular contraction).
A left-sided S3 is best heard in the left lateral decubitus position and at the apex of the heart, which is normally located in the 5th left intercostal space at the midclavicular line. A right-sided S3 is best heard at the lower left sternal border.
The left atrium is connected to the left ventricle by the mitral valve. [8] The left ventricle is much thicker as compared with the right, due to the greater force needed to pump blood to the entire body. Like the right ventricle, the left also has trabeculae carneae, but there is no moderator band. The left ventricle pumps blood to the body ...
Mitral valve or bicuspid valve, between the left atrium and left ventricle; Two semilunar valves to prevent the backflow of blood into the ventricle: Pulmonary valve, located at the opening between the right ventricle and the pulmonary trunk; Aortic valve, located at the opening between the left ventricle and the aorta.
When the action potential triggers the muscles in the atria to contract (atrial systole), the pressure within the atria rises further, pumping blood into the ventricles. During ventricular systole, pressure rises in the ventricles, pumping blood into the pulmonary trunk from the right ventricle and into the aorta from the left ventricle. [1]
Structures within the thoracic cavity include: structures of the cardiovascular system, including the heart and great vessels, which include the thoracic aorta, the pulmonary artery and all its branches, the superior and inferior vena cava, the pulmonary veins, and the azygos vein