Definition

1. Noun:
   • A specialized junction between two nerve cells (neurons), or between a neuron and a muscle or gland cell: A synapse is the tiny gap where the axon terminal of one neuron communicates with the dendrite or cell body of another neuron, or with an effector cell. Nerve signals cross this gap via chemical messengers called neurotransmitters.

Examples of Usage

• Noun:
  • The neurotransmitter dopamine is released into the synapse.
  • Learning and memory are believed to involve changes in the strength of synaptic connections.
  • The signal travels from one neuron to the next across a synapse.

Advanced Usage

• Synaptic transmission: The process by which a nerve impulse passes across a synapse.
  • Synaptic transmission can be excitatory or inhibitory.
• Synaptic cleft: The specific, narrow extracellular space that constitutes the gap within a synapse.
  • Neurotransmitters diffuse across the synaptic cleft.
• Synaptic plasticity: The ability of synapses to strengthen or weaken over time, fundamental to learning.
  • Researchers study synaptic plasticity to understand memory formation.

Variants and Related Words

• Synaptic (adjective): Of or relating to a synapse or synapses.
  • Synaptic vesicles store neurotransmitters.
• Synapsis (noun): In cell biology, the pairing of homologous chromosomes during meiosis. (Note: This is a different, specialized biological term and not a variant of the neural 'synapse', but they share a common etymological root meaning "connection").
• Postsynaptic (adjective): Referring to the cell (neuron, muscle) that receives the signal on the far side of the synapse.
  • The postsynaptic membrane contains receptor proteins.
• Presynaptic (adjective): Referring to the neuron that sends the signal from the axon terminal side of the synapse.
  • Calcium ions enter the presynaptic terminal to trigger neurotransmitter release.

Synonyms

• Neural junction: A less common but descriptive term for a synapse.
• Neuroeffector junction: Specifically refers to a synapse between a neuron and a muscle or gland cell.

Related Phrases

• To form a synapse: The process by which a neuronal connection is established.
  • The developing axon must find the correct target cell to form a synapse with.
• Synaptic integration: The process by which a neuron computes all the incoming signals from its many synapses.
  • A neuron's firing depends on the synaptic integration of excitatory and inhibitory inputs.

Related Idioms

• Given its technical, scientific nature, it is not commonly used in idiomatic expressions. However, it is sometimes used metaphorically in phrases like "a synaptic connection" to describe a sudden idea or mental link.
  • Reading that old letter created a synaptic connection to a forgotten memory.

Noun

1. the junction between two neurons (axon-to-dendrite) or between a neuron and a muscle
   • nerve impulses cross a synapse through the action of neurotransmitters