November 5, 2020

Muscle contraction/relaxation

Muscle contraction

 usually stops when signaling from the motor neuron ends, which repolarizes the sarcolemma and T-tubules, and closes the voltage-gated calcium channels in the SR. Ca++ ions are then pumped back into the SR, which causes the tropomyosin to reshield (or re-cover) the binding sites on the actin strands.1

Magnesium has a strong interaction with calcium. It suspends and regulates calcium so calcium can function better.

  1. https://opentextbc.ca/anatomyandphysiology/chapter/10-3-muscle-fiber-contraction-and-relaxation/