KIN202 Lecture 4: Unit 3 Skeletal Muscle Structure & Function Part 2
20 Jan 2019
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Unit 3 skeletal muscle structure and function part 2. Role of atp and atp-hydrolysis products during cross bridge cycle. Allows atp to rebind after completion of power-stroke. Membrane repolarization: k+ channels open and k+ leaves the cell must, the na+ & k+ concentration gradients must be restored (na+/k+-atpase) Cytosolic ca2+ concentration must be returned to normal: 50-100 nm at rest, accomplished by the sr ca2+-atpase or serca [sarco(endo)plasmic. The motor neuron and all of the fibres that it innervates. Smallest amount of muscle that can be activated voluntarily. Recruitment of motor units is the most important means of controlling muscle tension. Once recruited, all fibre in a motor unit will contract simultaneously. The nervous system controls force produced by controlling: Increase the frequency of action potential in the motor neuron: recruit more motor neurons (e. g. motor units) 1 motor neurons innervate type ii fibres. 2 motor neurons innervate type i fibres.
