How does acetylcholine transmit the nervous impulse across a synapse?

MYTUTOR SUBJECT ANSWERS

Answers / Biology / A Level / How does acetylcholine transmit the nervous impulse across a synapse?

378 views

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.

10 months ago

Answered by Charlotte, an A Level Biology tutor with MyTutor

Still stuck? Get one-to-one help from a personally interviewed subject specialist

263 SUBJECT SPECIALISTS

Bethany S. GCSE Chemistry tutor, A Level Chemistry tutor, GCSE Biolog...

View profile

£20 /hr

Bethany S.

Degree: Medicinal and biological chemistry (Integrated Masters) - Nottingham University

Subjects offered:Biology, Maths+ 1 more

“Hi! I'm a Chemistry student studying at the University of Nottingham with a passion for science that I'd love to pass on to my tutees!”

MyTutor guarantee

Save profile

Emma M. GCSE Biology tutor, IB Biology tutor, A Level Biology tutor, ...

View profile

£20 /hr

Emma M.

Degree: Bachelor of Medicine, Bachelor of Surgery (Bachelors) - Exeter University

Subjects offered:Biology, Spanish+ 2 more

“A friendly medical student with lots of experience in tutoring who would love to help you!”

MyTutor guarantee

Save profile

Christopher B. GCSE Biology tutor, A Level Biology tutor, GCSE Chemis...

View profile

£20 /hr

Christopher B.

Degree: Medicine (Bachelors) - St. Andrews University

Subjects offered:Biology, Maths+ 3 more

“I'm a straight A* medical student at the University of St Andrews. I have a patient and personal approach to tutoring. Let's arrange a free meeting!”

5.0