Exam Focus

The nervous system is a high-frequency topic in Unit 6 / Topic 7, appearing across all exam boards. Expect 4-8 marks, often combined with the reflex arc or reaction time practical.

How it is tested:

• Describe the pathway (2-3 marks): Sequence from stimulus to response — name each neurone type.
• Explain synapse transmission (3-4 marks): Four steps: impulse arrives → neurotransmitter released → diffuses and binds → new impulse.
• Compare nervous and hormonal systems (4 marks): Speed, duration, specificity — give BOTH sides for each comparison point.
• RPA7 reaction time (3-4 marks): Variables, controls, why repeat and average.
• Higher tier — Brain regions (2-3 marks): Name and state the function of cerebrum, cerebellum, medulla.
• Higher tier — Eye and accommodation (4-6 marks): Label eye parts, explain how the lens changes shape for near/far objects, describe myopia/hyperopia correction.

Edexcel 1BI0 — Paper 2 (1BI0/2) Notes

On Edexcel Paper 2, the nervous system appears in Topic 7: Animal Coordination, Control and Homeostasis. Edexcel-specific points to note:

• Stimulus-based synapse questions: Edexcel commonly provides a diagram of a synapse or an electron micrograph and asks you to "explain the sequence of events" at the synapse. Your answer must include: (1) impulse arrives at pre-synaptic membrane, (2) neurotransmitter released from vesicles by exocytosis, (3) diffuses across the gap, (4) binds to receptors on post-synaptic membrane, (5) new electrical impulse generated. Missing the exocytosis step or the receptor-binding step costs marks.
• Drug and toxin application ("Suggest"): Edexcel frequently asks "Suggest how a drug that blocks neurotransmitter receptors would affect nerve transmission." Follow the chain: no binding → no new impulse generated → pathway blocked → no response. This is a standard "Suggest" application question.
• RPA7 scenario questions: Edexcel presents the ruler-drop experiment as a scenario with student data, then asks you to identify anomalous results, explain why repeats are needed, and suggest one variable that was not controlled. Practise spotting anomalies in data tables.
• Extended writing: Edexcel 6-mark questions on the nervous system often ask you to compare nervous and hormonal coordination "using the information and your own knowledge." Structure your answer: speed (fast vs slow), duration (short vs long-lasting), target (specific effector vs widespread), and chemical messenger type (neurotransmitter vs hormone).