Explain the neuromuscular junction

Action potential causes depolarisation in the presynaptic bulb, this causes voltage-gated calcium channels to open. This causes vesicles containing the neurotransmitter acetycholine to move and fuse with the presynaptic membrane, hence acetylcholine is released into the synaptic cleft by exocytosis. Acetylcholine diffuses across the synapse and bind to acetylcholine receptors on the post-synaptic membrane. This causes voltage-gated sodium channels on the sarcolemma to open and sodium from the synaptic cleft to move into the sarcoplasm causing depolarisation. This depolarisation spreads across the sarcoplasm by T-tubules. This depolarisation causes the sarcoplasmic reticulum to release calcium into the sarcoplasm, which will then be used by the muscles for contraction.

ZO
Answered by Zahra O. Biology tutor

7913 Views

See similar Biology A Level tutors

Related Biology A Level answers

All answers ▸

What are the roles of the parasympathetic and sympathetic nervous systems?


Give one piece of evidence that supports the theory that mitochondria evolved from prokaryotic cells.


When do mutations not cause a change in amino acid sequence?


What is the difference between gene transcription and gene translation?


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