🔬general biology i review

Synaptic cleft

Written by the Fiveable Content Team • Last updated September 2025
Written by the Fiveable Content Team • Last updated September 2025

Definition

The synaptic cleft is the small gap between the presynaptic neuron and the postsynaptic cell where neurotransmission occurs. It allows for the transfer of chemical signals via neurotransmitters to propagate nerve impulses.

5 Must Know Facts For Your Next Test

  1. The synaptic cleft typically measures about 20-40 nanometers in width.
  2. Neurotransmitters released from synaptic vesicles cross the synaptic cleft to bind with receptors on the postsynaptic cell membrane.
  3. Enzymes in the synaptic cleft can break down neurotransmitters to terminate the signal transmission.
  4. Calcium ions play a crucial role in triggering neurotransmitter release into the synaptic cleft.
  5. The efficiency and speed of neurotransmission across the synaptic cleft are essential for proper nervous system function.

Review Questions

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