Synapses Flashcards

All 4 cards in this deck

What is a synapse?

A gap between two neurones.

What are the steps in transmitting an impulse across a synapse?
e.g. from a relay neurone to a motor neurone in a reflex arc

1. The electrical impulse arriving triggers the release of a chemical (neurotransmitter) — released by the relay neurone
2. The neurotransmitter diffuses across the synapse and binds to receptors on the next neurone — the motor neurone
3. A new electrical impulse is triggered in the next neurone — the motor neurone

Why is transmission across a synapse slower than transmission along an axon?

The neurotransmitter has to diffuse across the gap, which is slower than an electrical impulse travelling along an axon.

True or false? An impulse can cross a synapse in either direction.

False. Transmission is one-directional: only one neurone releases neurotransmitter and only the next neurone has the receptors for it.