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EC coupling results in the sequential contraction of the heart muscles that allows blood to be pumped, first to the lungs (pulmonary circulation) and then around the rest of the body (systemic circulation) at a rate between 60 and 100 beats every minute, when the body is at rest. [2]
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. [1] [2] These ...
Modalities applied to measurement of ejection fraction is an emerging field of medical mathematics and subsequent computational applications. The first common measurement method is echocardiography, [7] [8] although cardiac magnetic resonance imaging (MRI), [8] [9] cardiac computed tomography, [8] [9] ventriculography and nuclear medicine (gated SPECT and radionuclide angiography) [8] [10 ...
The work loop technique is used in muscle physiology to evaluate the mechanical work and power output of skeletal or cardiac muscle contractions via in vitro muscle testing of whole muscles, fiber bundles or single muscle fibers.
[1] Heart murmurs are abnormal heart sounds which can be either pathological or benign and there are numerous kinds. [10] Murmurs are graded by volume, from 1) the quietest, to 6) the loudest, and evaluated by their relationship to the heart sounds and position in the cardiac cycle. [9] Phonocardiograms can record these sounds. [1]
An increase in sympathetic stimulation to the heart increases contractility and heart rate. An increase in contractility tends to increase stroke volume and thus a secondary increase in preload. An increase in preload results in an increased force of contraction by Starling's law of the heart; this does not require a change in contractility.
First, atrial contraction feeds blood into the ventricles, then ventricular contraction pumps blood out of the heart to the body systems, including the lungs for resupply of oxygen. Cardiac systole is the contraction of the cardiac muscle in response to an electrochemical stimulus to the heart's cells ( cardiomyocytes ).
By contrast, skeletal muscle consists of multinucleated muscle fibers and exhibits no intercalated discs. Intercalated discs support synchronized contraction of cardiac tissue in a wave-like pattern so that the heart can work like a pump. [ 1 ]