Synaptic Transmission

Flussdiagrammknoten

• An impulse arrives at the presynaptic knob

• Post-synaptic membrane depolarised causing action potential

• Voltage-dependant calcium channels open, causing influx of Ca+ ions

• Synaptic vesicles contain acetylcholine bind to presynaptic membrane and releases neurotransmitter by exocytosis into synaptic cleft

• Neurotransmitter diffuses to receptor on a protein on post-synaptic membrane

• Co-operative binding on receptor: 2 receptor sites

• Threshold reached (-55mV)

• Channel opens and Na+ ions diffuse in

• Acetylcholine hydrolysed or destroyed by enzyme