How does acetylcholine transmit the nervous impulse across a synapse?

An action potential from the axon arrives at the presynaptic neuron, stimulating voltage-gated calcium (Ca2+) ion channels to open. This allows calcium ions to diffuse into the synaptic knob, causing synaptic vesicles containing acetylcholine (the neurotransmitter) to fuse with the presynaptic membrane and release into the synaptic cleft: exocytosis. Acetylcholine then diffuses across the synaptic cleft and binds to cholinergic receptors on the postsynaptic membrane, causing ligand-gated sodium (Na+) channels to open. This results in the facilitated diffusion of sodium into the postsynaptic membrane - causing an action potential if threshold is reached. Acetylcholinesterase then breaks down the neurotransmitter to prevent continuous stimulation. 

Answered by Charlotte C. Biology tutor

4055 Views

See similar Biology A Level tutors

Related Biology A Level answers

All answers ▸

What are the four stages of aerobic respiration in humans?


Draw a genetic diagram to show how unaffected parents could have a son with Haemophilia but also other children who do not suffer from the disease.


Describe how phagocytosis of a virus leads to the secretion of an antibody against this virus antigen.


What is artificial life?


We're here to help

contact us iconContact usWhatsapp logoMessage us on Whatsapptelephone icon+44 (0) 203 773 6020
Facebook logoInstagram logoLinkedIn logo

© MyTutorWeb Ltd 2013–2025

Terms & Conditions|Privacy Policy
Cookie Preferences