The Synapse: Your Nervous System’s “Messenger Bridge” - Extended

What is a Synapse?

• A synapse is the small gap between two neurones. It acts as a bridge for signals to pass from one neurone to the next.
• Synapse signals travel in only one direction
• Instead of directly jumping across, signals are transmitted by chemicals called neurotransmitters. 
• As the synapse is the only place where the nervous system uses chemicals, drugs can affect this area, i.e heroin.

Analogy: Imagine two people passing a note. The space between them (synapse) requires someone (neurotransmitters) to deliver the message.

 

Structure of a Synapse

Part	Function
Synaptic Gap	The tiny space between two neurones where neurotransmitters are released.
Vesicles	Small sacs in the end of a neurone containing neurotransmitters.
Receptor Proteins	Found on the surface of the next neurone; they receive neurotransmitters.

 

 

How a Signal Travels Across a Synapse

1. Impulse Arrival:

   • An electrical impulse reaches the end of a neurone (axon terminal).

2. Release of Neurotransmitters:

   • Vesicles release neurotransmitters into the synaptic gap.

3. Diffusion Across the Gap:

   • Neurotransmitters diffuse across the synaptic gap.

4. Binding to Receptors:

   • Neurotransmitters bind to receptor molecules (proteins) on the next neurone.

5. New Impulse Generated:

   • A new electrical impulse is triggered in the next neurone.
6. Neurotransmitter destroyed:
   • Once the new impulse is generated the neurotransmitter is destroyed to stop more impulses being triggered.

 

Why Are Synapses Important?

Feature	Purpose
Ensures One-Way Travel	Signals only travel in one direction, maintaining order in the nervous system.
Control of Signals	Neurotransmitters ensure signals are sent only when needed.
Filter for Important Signals	Not all signals are passed on; some are stopped for efficiency.