Nerve Impulses, Synapses & Neurotransmitters

Explaining how messages travel

What is a nerve impulse?

An electrical message that travels along a neuron

What is the pathway of a nerve impulse?

Stimulus > Receptor > Sensory neuron > CNS > Interneuron > Motor neuron > Effector > Response

What is a stimulus?

A change in the environment detected by receptors eg. light, sound, heat, pressure

What is a receptor?

A specialised cell that detects a stimulus

What is an effector?

A muscle or gland that creates a response

What is a synapse?

The small gap between two neurons

Why don’t neurons directly touch each other?

Because there is a small gap called the synapse where chemical messages pass

What are neurotransmitters?

Chemicals that carry messages across the synapse between neurons

How does a message cross a synapse?

Electrical impulse reaches axon terminal, neurotransmitters are released, they cross the synapse, another neuron receives the message and the impulse continues