This topic summary covers Knowledge Organiser within Nervous System for GCSE Biology. Topic 2: Nervous System It is section 16 of 17 in this topic. Use this topic summary to connect the idea to the wider topic before moving on to questions and flashcards.
Topic position
Section 16 of 17
Practice
15 questions
Recall
20 flashcards
📊 Knowledge Organiser
Key Terms
- CNS — brain + spinal cord; coordination centre
- Sensory neurone — receptor to CNS
- Relay neurone — within CNS; connects sensory to motor
- Motor neurone — CNS to effector
- Synapse — gap crossed by neurotransmitters
- Cerebrum — consciousness, memory, language
- Cerebellum — coordination, balance
- Medulla — heart rate, breathing rate
- Accommodation — lens shape change for focus
- Retina — rods (dim light) and cones (colour)
Must-Know Facts
- Pathway: stimulus → receptor → sensory → CNS (relay) → motor → effector → response
- Nervous: fast, short-lived, precise. Hormonal: slower, long-lasting, widespread
- Synapse: release → diffuse → bind → trigger new impulse (RDBT)
- Near focus: ciliary muscles contract → ligaments loosen → lens thick
- Far focus: ciliary muscles relax → ligaments tight → lens thin
- Myopia: concave lens. Hyperopia: convex lens
- RPA7: ruler-drop, repeat 5+ times, calculate mean
Common Marks Lost
- Writing "nerve" instead of "neurone" (a nerve is a bundle of neurones)
- Not naming all three neurone types in pathway questions
- Getting ciliary muscle contraction/relaxation wrong for accommodation
- Saying reflexes don't involve the CNS (they do — via the spinal cord)
- Forgetting to compare BOTH systems in nervous vs hormonal questions