How is a nervous impulse transmitted across a synapse?

An action potential (AP) reaches the pre-synaptic membrane. This causes the voltage-gated calcium channels to open, and calcium ions flow down their concentration gradient into the pre-synaptic terminal. This then causes vesicles containing neurotransmitter (NT) molecules to fuse their membrane with the pre-synaptic membrane. In this way, the NT is released into the synaptic cleft and diffuses across it. When it reaches the post-synaptic membrane, it binds to receptors on its surface, which in turn causes sodium ion channels to open, letting sodium ions to flow down their concentration gradient into the post-synaptic neuron. This generates a new AP in the post-synaptic neuron.

Answered by Teodora N. Biology tutor

1872 Views

See similar Biology A Level tutors

Related Biology A Level answers

All answers ▸

How should I revise?


Describe the key feature of stem cells and discuss their applications in research and medicine. Please provide examples.


Briefly describe the main differences between fast and slow twitch muscles and how does this relate to their specific functions.


How does cholera cause diarrhoea and dehydration?


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