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calcium channel

a voltage-gated ion channel in the presynaptic membrane of a neuron that is involved in the release of neurotransmitter (and, therefore, passage of a neural signal) at a synapse. The arrival of an action potential at the terminal buttons (see axon) of the neuron is accompanied by depolarization of the presynaptic membrane, which results in opening of the calcium channels and influx of calcium ions into the terminal buttons. This triggers fusion of the synaptic vesicles (which contain neurotransmitter) with the presynaptic membrane and the release of neurotransmitter into the synaptic cleft.

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Psychology term of the day

January 30th 2025

vowel

vowel

n.

1. a voiced speech sound that is produced when the breath stream vibrating the vocal cords has unobstructed passage through the vocal tract.

2. one of the letters of the alphabet used to represent these sounds in writing. Compare consonant.