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The cardiac cycle is the performance of the human heart from the beginning of one heartbeat to the beginning of the next. It consists of two periods: one during which the heart muscle relaxes and refills with blood, called diastole, following a period of robust contraction and pumping of blood, dubbed systole. After emptying, the heart ...
Within the muscle tissue of animals and humans, contraction and relaxation of the muscle cells is a highly regulated and rhythmic process. In cardiomyocytes, or cardiac muscle cells, muscular contraction takes place due to movement at a structure referred to as the diad , sometimes spelled "dyad."
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 ]
Cardiac muscle tissue has autorhythmicity, the unique ability to initiate a cardiac action potential at a fixed rate – spreading the impulse rapidly from cell to cell to trigger the contraction of the entire heart. This autorhythmicity is still modulated by the endocrine and nervous systems. [1]
The trabeculae carneae and the papillary muscles make up a significant percentage of the ventricular mass in the heart (12-17% in normal human adult hearts), and are correlated with ventricular end diastolic volume. [5] Trabeculae ratios of capillary-to myocyte differ between the walls of the right and left ventricle.
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 ...
The muscular system is an organ system consisting of skeletal, smooth, and cardiac muscle. It permits movement of the body, maintains posture, and circulates blood throughout the body. [1] The muscular systems in vertebrates are controlled through the nervous system although some muscles (such as the cardiac muscle) can be
T-tubules (transverse tubules) are extensions of the cell membrane that penetrate into the center of skeletal and cardiac muscle cells.With membranes that contain large concentrations of ion channels, transporters, and pumps, T-tubules permit rapid transmission of the action potential into the cell, and also play an important role in regulating cellular calcium concentration.