Explain the route and role of calcium ions in the Sliding Filament theory of muscle contraction

ROUTE: when an action potential arrives at the neuromuscular junction, Calcium ions are released from the sarcoplasmic reticulum, into the sarcoplasm, where they bind to the troponin molecules on the tropomyosin. After contraction of the muscle fibre, the calcium ions are taken up by the sarcoplasmic reticulum for relaxation of the muscle. ROLE: When the calcium ions bind to troponin, they cause the tropmyosin molecules to move out of the way to expose the myosin binding sites on the actin filament. The abundance of calcium ions in the sarcoplasm regulates the contraction and relaxation of the muscle fibre.

EC
Answered by Erin C. Biology tutor

16903 Views

See similar Biology A Level tutors

Related Biology A Level answers

All answers ▸

Describe the structure of proteins


In a population of 1000 lemmings there are two alleles for skin colour, the dominant colour being cream (C) and the recessive being white (c). 350 individuals have white skin. Use Hardy-Weinberg to predict the number of homozygous recessive individuals.


Outline how a heartbeat is initiated and controlled


state 3 difference between DNA replication and transcription of DNA


We're here to help

contact us iconContact ustelephone icon+44 (0) 203 773 6020
Facebook logoInstagram logoLinkedIn logo

MyTutor is part of the IXL family of brands:

© 2025 by IXL Learning