Modeling And Simulation Of Skeletal Muscle Rapid Fiber Excitation Contraction

Fast fiber of skeletal muscle is a kind of muscle fiber.Compared with slow fiber,fast fibers have physiological characteristics of a higher density of ion channel,faster2Ca+release and uptake,more rapid cross-bridge cycling and quicker twitch response and more easy fatigue of fast fibers.Therefore,based on the physical properties of skeletal muscle fast fiber,the corresponding model is established to simulate skeletal muscle fast excitation contraction of muscle physiological process,for healing,muscle related disease diagnosis and sports provide theoretical guidance is of great significance.Firstly,the action potential of the fast muscle fiber film and the transverse membrane were established according to the two-compartment model.Using the Hodgkin-Huxley electrophysiological model,the Na+ current,delayed rectifier K+ current,inward rectifier K+ current,Cl-current and Na+-K+ pump current on the fast muscle fiber membranes and transverse membranes are described.The Goldman-Hodgkin-Katz driving force equation was used as the power of ions to pass through the membrane.The membrane fatigue due to the slow inactivation of Na+? K+ channels and the accumulation of K+ in the horizontal tubes was analyzed.Secondly,a 10-state model was established to simulate the coupling between the dihydropyridine voltage receptor(DHPR)on the lateral tube membrane and the Reynold's channel(RYR)in the final cell to control the Ca2+ release in the final cell.According to the symmetrical physiological geometry of muscle segments,the half muscle segment was divided into six regions to simulate the change of Ca2+ concentration in each region.Thirdly,according to the relative position of the thick and thin filaments,a 6-state model was established in the completely non-overlapping region to simulate the binding of Ca2+ and troponin,and the 6-state and 8-state models were established in the completely overlapping region and the partially overlapping region to simulate Ca2+ and muscle Calmodulin binding and cross-bridge cycling.Establish a model of fatigue caused by metabolism during the cross-bridge circulation.Finally,Simulink in MATLAB was used to simulate and verify the model of excitability and contraction of skeletal muscle fast muscle fibers.Analysis of Ca2+ circulation,transverse bridge force and fatigue in three different relative positions of the slender muscle filaments under the single contraction and different frequency stimulating contractions.