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In a healthy heart all activities and rests during each individual cardiac cycle, or heartbeat, are initiated and orchestrated by signals of the heart's electrical conduction system, which is the "wiring" of the heart that carries electrical impulses throughout the body of cardiomyocytes, the specialized muscle cells of the heart.
Heart sounds are the noises generated by the beating heart and the resultant flow of blood through it. Specifically, the sounds reflect the turbulence created when the heart valves snap shut. In cardiac auscultation , an examiner may use a stethoscope to listen for these unique and distinct sounds that provide important auditory data regarding ...
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 first heart sound S1, is the sound created by the closing of the atrioventricular valves during ventricular contraction and is normally described as "lub". The second heart sound, S2, is the sound of the semilunar valves closing during ventricular diastole and is described as "dub". [8]
At the peak of arousal (0:57), orgasm occurs and semen is ejaculated from the penis in a series of rhythmic contractions. (In this demonstration, there are 15 strong contractions followed by 10 weaker contractions). Once arousal has peaked (1:35), the penis returns to its flaccid state, the scrotum loosens, and the testicles descend.
In order to maximize efficiency of contractions and cardiac output, the conduction system of the heart has: Substantial atrial to ventricular delay. This will allow the atria to completely empty their contents into the ventricles; simultaneous contraction would cause inefficient filling and backflow.
Electrical waves track a systole (a contraction) of the heart. The end-point of the P wave depolarization is the start-point of the atrial stage of systole. The ventricular stage of systole begins at the R peak of the QRS wave complex; the T wave indicates the end of ventricular contraction, after which ventricular relaxation (ventricular diastole) begins.
A transthoracic echocardiogram (TTE) is the most common type of echocardiogram, which is a still or moving image of the internal parts of the heart using ultrasound.In this case, the probe (or ultrasonic transducer) is placed on the chest or abdomen of the subject to get various views of the heart.