Describe the transmission of a nerve impulse across a synapse.

An action potential arrives at a presynaptic neurone, which causes calcium ion channels to open. Calcium ions enter the presynaptic knob, which causes synaptic vesicles containing neurotransmitter to detach from the cytoskeleton. These move towards the presynaptic membrane. The vesicles fuse with the membrane and release the neurotransmitter which diffuses across the synaptic cleft. The neurotransmitter binds to complementary receptors on the postsynaptic membrane, which opens sodium ion channels. This leads to depolarisation and if this reaches the threshold, an action potential will fire.

Answered by Biology tutor

5287 Views

See similar Biology A Level tutors

Related Biology A Level answers

All answers ▸

Describe how a protein molecule is produced from mRNA


What are two protein filaments that interact in the sarcomere to cause muscular contraction?


Effect of enzyme concentration in excess substrate on enzyme catalysed reaction


give two features of DNA that is important for DNA replication


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