What is the term for EC coupling in cardiac muscle?
Cardiac excitation-contraction coupling (Cardiac EC coupling) describes the series of events, from the production of an electrical impulse (action potential) to the contraction of muscles in the heart.
What triggers excitation contraction coupling?
In summary, acetylcholine initiates the excitation-contraction coupling, and calcium binding to troponin initiates muscle contraction. A muscle twitch is synonymous to a single contraction-relaxation cycle in a skeletal muscle fiber.
What regulates myocyte relaxation?
The predominant mechanism for lowering calcium to promote relaxation (see also Figure 2-7) is the ATP-dependent reuptake of calcium into the longitudinal sarcoplasmic reticulum via the actions of sarcoplasmic reticulum calcium pumps, which are in turn regulated by the phosphorylation state of phospholamban.
What do we mean by excitation contraction coupling?
First coined by Alexander Sandow in 1952, the term excitation-contraction coupling (ECC) describes the rapid communication between electrical events occurring in the plasma membrane of skeletal muscle fibres and Ca2+ release from the SR, which leads to contraction.
Why is excitation contraction coupling important?
Much of the Ca needed for contraction comes from the sarcoplasmic reticulum and is released by the process of calcium-induced calcium release. The process of excitation–contraction (E–C) coupling links the electric excitation of the surface membrane (action potential) to contraction.
What is excitation-contraction coupling in anatomy?
Excitation–contraction coupling is the physiological process of converting an electrical stimulus to a mechanical response. It is the link (transduction) between the action potential generated in the sarcolemma and the start of a muscle contraction.
What does the term cardiac excitation-contraction coupling mean?
Cardiac excitation-contraction coupling (Cardiac EC coupling) describes the series of events, from the production of an electrical impulse (action potential) to the contraction of muscles in the heart.
How is ECC impaired in systolic heart failure?
In systolic heart failure, ECC can be impaired at several different sites. First, there can be decreased influx of calcium into the cell through L-type calcium channels (resulting from impaired signal transduction ), which decreases subsequent calcium release by the SR.
How is ECC related to cardiomyocyte contraction?
ECC translates electrical signals originating from pacemaker cells and distributed through the heart wall by Purkinje fibers, to cardiomyocyte contraction. Judith A. Heiny, Gerhard Meissner, in Cell Physiology Source Book (Fourth Edition), 2012 EC coupling can be modulated in response to different demands of muscle use.
What happens at the end of the cardiac excitation cycle?
At the end of the cycle, a new ATP binds to the myosin head, displacing the ADP, and the initial sarcomere length is restored. Mechanisms that enhance the concentration of cytosolic calcium increase the amount of ATP hydrolyzed and the force generated by the actin and myosin interactions, as well as the velocity of shortening.