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Science

Neuroscience: How the Brain Works

Overview

Students explore the cellular mechanisms of nervous system function, discovering how electrical signals travel along neurons and are transmitted chemically between them.

Learning Objective
Students understand how nerve impulses are transmitted along neurons and across synapses, and can connect this to learning and memory.

Resources needed

  • None

Lesson stages

0 / 7 done
  1. 1 Recap: the nervous system consists of neurons — specialised cells that transmit electrical signals.
  2. 2 Introduce the resting potential: at rest, the inside of a neuron is more negative than the outside (approximately -70 mV) due to the unequal distribution of ions.
  3. 3 Introduce the action potential: when a neuron is stimulated sufficiently, sodium ions rush in, reversing the charge. This electrical signal travels along the axon.
  4. 4 Introduce the all-or-nothing principle: a neuron either fires (action potential) or does not. The strength of the stimulus determines how many neurons fire and how often, not the size of each signal.
  5. 5 Introduce the synapse: the gap between two neurons. When the action potential reaches the end of the neuron, neurotransmitters are released into the synapse.
  6. 6 Neurotransmitters bind to receptor proteins on the next neuron, triggering (or inhibiting) a new action potential.
  7. 7 Introduce how drugs affect the synapse: stimulants increase neurotransmitter release or block their reuptake; depressants mimic inhibitory neurotransmitters or block excitatory ones.

Tap a step to mark it as done.

Variations

  • Discuss synaptic plasticity: repeated firing of a synapse strengthens it — the cellular basis of learning and memory.
  • Discuss neurodegenerative diseases: Parkinson's (too little dopamine) and Alzheimer's (loss of synaptic connections).
  • Model the action potential as a class: students stand in a line, each one fires (sits down then stands) after the one before — the wave travels along the line.
More information

Teach: neuron, action potential, resting potential, synapse, neurotransmitter, receptor, all-or-nothing, myelin. The key sequence: electrical signal along axon, chemical signal across synapse, electrical signal in next neuron.

Focus on the action potential and its propagation before introducing synaptic transmission.

Can students describe the sequence of events from stimulus to response, including both electrical and chemical transmission? Can they explain the all-or-nothing principle?

No resources needed. The class model of action potential propagation requires only space and students. This is a conceptual and discussion-based lesson.

Students often think the electrical signal jumps across the synapse. There is a gap between neurons — the signal crosses chemically via neurotransmitters, not electrically. The chemical-to-electrical conversion at the post-synaptic membrane is the critical step.

Neuroscience is one of the most rapidly advancing areas of biology. Understanding synaptic transmission is essential for pharmacology, psychiatry, and neurology — and for understanding how learning itself works at the cellular level.

Activity details
Secondary Challenging 25 minutes no prep Whole Class, Small Group Indoor & Outdoor
Topics
Neuroscience Synapses Action Potential