BRAINCAKETransmission of Impulse across Synapse
When an action potential reaches the pre-synaptic bulb, calcium ion channels open.
Ca2+ ions diffuse into the pre-synaptic neurone.
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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
- Nerve Impulse
- Saltatory Conduction
- Synapses
- Neurotransmitters
- The Role of Synapses
- Summation
- Structural Organisation of the Nervous System
- Functional Organisation of the Nervous System
All 38 lessons in Neuronal Communication · All AQA A-level Biology topics