How is an action potential (AP) transmitted across a synapse?

As an action potential (AP) arrives at the synaptic knob and depolarises the presynaptic membrane, voltage-gated Ca2+ channels open, allowing the entry of Ca2+ ions, This caues vesicles (membrane-bound organelle within cytoplasm) containing various neurotransmitters (e.g. acetylcholine) to move towards and fuse with the presynaptic membrane. The neurotransmitters are released, they diffuse across the syanptic cleft and bind to the corresponding receptors on the postsynaptic membrane. This then causes Na+ channels to open, allowing influx of Na+ ions. The postsynaptic membrane depolarises, and an AP is sent down the axon following the synapse once the threshold for AP is reached. When the presynaptic membrane is no longer depolarised, neurotransmitters bound to receptors are broken down by a specific enzyme (e.g. acetylcholinesterase) and the products are recycled. 

YC
Answered by Young C. Biology tutor

6026 Views

See similar Biology A Level tutors

Related Biology A Level answers

All answers ▸

Why does putting honey on a cut kill the bacteria within it?


Describe how carbohydrates are broken down.


What is the difference between transcription and translation?


How do synapses work?


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