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. 

CC
Answered by Charlotte C. Biology tutor

4257 Views

See similar Biology A Level tutors

Related Biology A Level answers

All answers ▸

How is blood glucose controlled in homeostasis?


What are the events that lead to synaptic transmission between two neurons?


What's the difference between the cell wall and cell membrane?


What do I do with the Hardy-Weinberg equation?


We're here to help

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

© MyTutorWeb Ltd 2013–2025

Terms & Conditions|Privacy Policy
Cookie Preferences