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A Wiggers diagram modified from [1]. A Wiggers diagram, named after its developer, Carl Wiggers, is a unique diagram that has been used in teaching cardiac physiology for more than a century.
The isovolumetric contraction phase lasts about 0.05 seconds, [1] but this short period of time is enough to build up a sufficiently high pressure that eventually overcomes that of the aorta and the pulmonary artery upon opening of the semilunar valves. This process, therefore, helps maintain the correct unidirectional flow of blood through the ...
The semilunar valves (the pulmonary and aortic valves) are formed from four thickenings at the cardiac end of the truncus arteriosus. [9] These thickenings are called endocardial cushions . [ citation needed ] The truncus arteriosus is originally a single outflow tract from the embryonic heart that will later split to become the ascending aorta ...
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 ...
Aneurysm of the aortic sinus, also known as the sinus of Valsalva, is a rare abnormality of the aorta, the largest artery in the body.The aorta normally has three small pouches that sit directly above the aortic valve (the sinuses of Valsalva), and an aneurysm of one of these sinuses is a thin-walled swelling.
Mitral valve prolapse: This is the most common cause of late systolic murmurs. It can be heard best over the apex of the heart, usually preceded by clicks. The most common cause of mitral valve prolapse is "floppy" valve (Barlow's) syndrome. If the prolapse becomes severe enough, mitral regurgitation may occur.
Heart sounds result from reverberation within the blood associated with the sudden block of flow reversal by the valves closing. Because of this, auscultation to determine function of a valve is usually not performed at the position of the valve, but at the position to where the sound waves reverberate. [citation needed]
The aortic and pulmonary valves known as the semilunar valves open, and a defined fraction of blood within the heart is ejected into the aorta and pulmonary trunk. Ejection of blood from the heart is known as systole. Ejection causes pressure within the ventricles to fall, and, simultaneously, the atria begin to refill (atrial diastole).