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Viewed through a microscope, cardiac muscle cells are roughly rectangular, measuring 100–150μm by 30–40μm. [9] Individual cardiac muscle cells are joined at their ends by intercalated discs to form long fibers. Each cell contains myofibrils, specialized protein contractile fibers of actin and myosin that slide past each other
The main function of striated muscle tissue is to create force and contract. These contractions in cardiac muscle will pump blood throughout the body. In skeletal muscle the contractions enable breathing, movement, and posture maintenance. [1] Contractions in cardiac muscle tissue are due to a myogenic response of the heart's pacemaker cells ...
Myocardial perfusion imaging or scanning (also referred to as MPI or MPS) is a nuclear medicine procedure that illustrates the function of the heart muscle (). [1]It evaluates many heart conditions, such as coronary artery disease (CAD), [2] hypertrophic cardiomyopathy and heart wall motion abnormalities.
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 ...
All cardiac muscle cells are electrically linked to one another, by intercalated discs which allow the action potential to pass from one cell to the next. [1] [2] This means that all atrial cells can contract together, and then all ventricular cells. Different shapes of the cardiac action potential in various parts of the heart
Moreover, live-cell imaging often employs special optical system and detector specifications. For example, ideally the microscopes used in live-cell imaging would have high signal-to-noise ratios, fast image acquisition rates to capture time-lapse video of extracellular events, and maintaining the long-term viability of the cells. [26]
For example, clinical cardiac electrophysiology is the study of the electrical properties which govern heart rhythm and activity. Cardiac electrophysiology can be used to observe and treat disorders such as arrhythmia (irregular heartbeat). For example, a doctor may insert a catheter containing an electrode into the heart to record the heart ...
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.