BRAINCAKESummation
Each action potential triggers the release of the same amount of neurotransmitter into the synaptic cleft.
Only if the amount of neurotransmitter is sufficient will an action potential be triggered in the post-synaptic neurone so there is a threshold.
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Key terms in this lesson
- neurotransmitter
- A chemical released by a presynaptic neurone that diffuses across a synapse and binds to receptors on the postsynaptic cell, altering its membrane potential.
- synaptic cleft
- The narrow, fluid-filled gap between the presynaptic and postsynaptic membranes at a synapse, across which neurotransmitters diffuse.
- action potential
- A rapid, temporary reversal of the electrical charge across an axon membrane (depolarisation followed by repolarisation) that occurs when a stimulus exceeds the threshold value.
More in Neuronal Communication
- Synapses
- Neurotransmitters
- Transmission of Impulse across Synapse
- The Role of Synapses
- Structural Organisation of the Nervous System
- Functional Organisation of the Nervous System
- The Autonomic Nervous System
- Comparison of Neurones
All 38 lessons in Neuronal Communication · All AQA A-level Biology topics