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Contraction of smooth muscle is initiated by a Ca 2+-mediated change in the thick filaments, whereas in striated muscle Ca 2+ mediates contraction by changes in the thin filaments. In response to specific stimuli in smooth muscle, the intracellular concentration of Ca 2+ increases, and this activator Ca 2+ combines with the acidic protein ...
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Ca2-DEPENDENT CONTRACTION OF SMOOTH MUSCLE Contraction of...
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Chętnie wyświetlilibyśmy opis, ale witryna, którą oglądasz,...
- Vol. 27, No. 4
Contractile activity in smooth muscle is initiated by a Ca...
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Smooth muscle contraction (left) requires five steps to perform: After the increase of intracellular Ca 2+ concentrations from either the extracellular fluid or the sarcoplasmic reticulum (1), these ions bind to a protein called calmodulin (2).
14 sie 2023 · Smooth muscle contraction depends on calcium influx. Calcium increases within the smooth muscle cell through two different processes. First, depolarization, hormones, or neurotransmitters cause calcium to enter the cell through L-type channels located in the caveolae of the membrane.
Smooth muscle cells rapidly redifferentiate in culture, entering a so-called proliferative or synthetic state characterized by reduced expression of contractile proteins, changes in cytoskeletal architecture, loss of dense bodies and disappearance of excitability mechanisms.
To initiate muscle contraction, tropomyosin has to expose the myosin-binding site on an actin filament to allow cross-bridge formation between the actin and myosin microfilaments. The first step in the process of contraction is for Ca ++ to bind to troponin so that tropomyosin can slide away from the binding sites on the actin strands. This ...
The process of muscle contraction begins at the site where a motor neuron’s terminal meets the muscle fiber—called the neuromuscular junction (NMJ). Every skeletal muscle fiber in every skeletal muscle is innervated by a motor neuron at a NMJ.
Like that of cardiac muscle, smooth muscle contraction is regulated by both extracellular and intracellular (SR) Ca 2+ stores, which can be activated by mechanical stretch or by G-protein-coupled receptors (GPCRs; e.g., α1-adrenergic receptors of vascular smooth muscle).
