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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.
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.
English: This video is an example of a man and woman having penile-vaginal intercourse in the standing position, a relatively normal example of sexual intercourse. It begins with the insertion of a man's erect penis into a woman's vagina at 0:07, followed by pelvic thrusts, becoming faster, initially to stimulate the vagina as it continues to lengthen and become lubricated.
The heart is a muscular organ found in humans and other animals. This organ pumps blood through the blood vessels. [1] Heart and blood vessels together make the circulatory system. [2] The pumped blood carries oxygen and nutrients to the tissue, while carrying metabolic waste such as carbon dioxide to the lungs. [3]
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.
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.
This rate can be altered, however, by nerves that work to either increase heart rate (sympathetic nerves) or decrease it (parasympathetic nerves), as the body's oxygen demands change. Ultimately, muscle contraction revolves around a charged atom (ion) , calcium (Ca 2+ ) , [ 3 ] which is responsible for converting the electrical energy of the ...
Image showing the cardiac pacemaker or SA node, the primary pacemaker within the electrical conduction system of the heart The cardiac pacemaker is the heart 's natural rhythm generator. It employs pacemaker cells that produce electrical impulses, known as cardiac action potentials , which control the rate of contraction of the cardiac muscle ...