When a nerve impulse arrives at a synapse, it causes the release of neurotransmitter from vesicles in the presynaptic knob. Describe how.
Membrane depolarisation arrives at the pre-synpase and causes Ca2+ voltage-gated channels to open. This allows Ca2+ ions to diffuse in the presynapse via the activated Ca2+ channels. Ca2+ influx in the presynapse induces vesicles carrying the neurotransmitter to fuse with the presynaptic membrane and release their content in the synaptic knob.
GM
Related Biology A Level answers
All answers ▸Describe the ionic basis of an action potential, and how this is reflected on the cell's membrane potential (6 marks)
Describe the cardiac cycle, including the role that valves and pressure differences play in this process.
What is the purpose and structure of a cell membrane?
Describe the way in which the normal heart beat is initiated and controlled