6)Excitation Contraction Coupling, Types of Muscular Contraction and Force-velocity Properties Part 1

Which structure ensures action potentials reach the interior of the muscle fibre?

T tubules

What receptor detects voltage change in the T tubule membrane?

Dihydropyridine (DHP) receptor

How is calcium moved back into the sarcoplasmic reticulum during relaxation?

Calcium ATPase (SERCA) pumps

Which molecule helps buffer calcium concentration inside the SR?

Calsequestrin

What allows the myosin head to detach from actin during the cross-bridge cycle?

ATP binding to the myosin head

What triggers the power stroke during muscle contraction?

Release of phosphate from the myosin head

What repositions the myosin head after detachment from actin?

Hydrolysis of ATP into ADP and phosphate

What causes the calcium channels in the SR to close during relaxation?

Repolarisation and return of DHP receptor to resting state

What maintains low intracellular sodium levels at rest in the muscle fibre?

Sodium ATPase pumps