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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.
Cardiac muscle (also called heart muscle or myocardium) is one of three types of vertebrate muscle tissues, the others being skeletal muscle and smooth muscle. It is an involuntary, striated muscle that constitutes the main tissue of the wall of the heart.
In both cardiac and skeletal muscles, muscular force production is controlled primarily by changes in intracellular calcium concentration. In general, when calcium rises, the muscles contract and, when calcium falls, the muscles relax. [citation needed] Troponin is a component of thin filaments (along with actin and tropomyosin), and is the protein complex to which calcium binds to trigger the ...
Cav1.2 is widely expressed in the smooth muscle, pancreatic cells, fibroblasts, and neurons. [9][10] However, it is particularly important and well known for its expression in the heart where it mediates L-type currents, which causes calcium-induced calcium release from the ER Stores via ryanodine receptors.
The main role of a sinoatrial node cell is to initiate action potentials of the heart that can pass through cardiac muscle cells and cause contraction. An action potential is a rapid change in membrane potential, produced by the movement of charged atoms (ions).
T-tubules within the heart are closely associated with the intracellular calcium store known as the sarcoplasmic reticulum in specific regions referred to as terminal cisternae. The association of the T-tubule with a terminal cisterna is known as a diad. [6]
A calcium spark is the microscopic release of calcium (Ca 2+) from a store known as the sarcoplasmic reticulum (SR), located within muscle cells. [1] This release occurs through an ion channel within the membrane of the SR, known as a ryanodine receptor (RyR), which opens upon activation. [2] This process is important as it helps to maintain Ca ...
Ryanodine receptor. Ryanodine receptors (RyR for short) form a class of intracellular calcium channels in various forms of excitable animal tissue like muscles and neurons. [1] There are three major isoforms of the ryanodine receptor, which are found in different tissues and participate in different signaling pathways involving calcium release ...