4.4 Control systems: How do organisms react to their environment?
Explain nervous responses and negative-feedback control of body temperature and blood glucose.
How to study WJEC GCSE The Sciences
Move from a scientific model to a prediction or method, collect or interpret evidence, show quantitative working and finish with a conclusion whose limits match the data.
Core concepts
Concept 1
Trace stimuli through receptors, the nervous system and effectors.
Exam cue: Identify the unit, entered tier, supplied reference material, command word and relevant scientific enquiry skill.
Concept 2
Explain thermoregulation using negative feedback.
Exam cue: Name the detected change, coordination pathway and effector response, then show how the response reverses the change.
Concept 3
Explain insulin and glucagon control of blood glucose.
Exam cue: Use scientific terminology, show quantitative working with units, and connect conclusions to data and the stated model.
Concept 4
Official subtopics: 4.4.1 The nervous system; 4.4.2 Control of temperature in humans; 4.4.3 Control of blood glucose in humans.
Concept 5
Scientific enquiry and mathematical skills apply in this topic; bold amplification is Higher Tier only.
Risk pitfalls and guardrails
Describing a response without completing the negative-feedback loop.
Guardrail: Do not import outgoing 3430QD content, another science route, a fixed required-practical list or unsupported tier and connection assumptions.
Recalling a fact without applying it to the observation, data, practical method or unfamiliar context.
Guardrail: Use the live secure pack: Task A may use groups of up to three; Task B is individual and highly controlled. Two enquiries are selected by the centre from three.
Importing content, required practicals, tier rules or paper structure from the outgoing WJEC or another awarding-body route.
Guardrail: Bold amplification is Higher-only. Units 1-6 may mix tiers, but Unit 7 is untiered.
Memory anchors
Stimulus
A change detected by a receptor.
Receptor
A cell or organ that detects a stimulus.
Effector
A muscle or gland that produces a response.
Homeostasis
Regulation of internal conditions around suitable levels.
Negative feedback
A control response that counteracts a detected change.
Checkpoint rule
Do the check-up only after you can summarize each concept in one sentence and identify one dangerous pitfall from memory.
Knowledge Check (after reading)
Short check-up to confirm understanding of this module.
Check-up Questions
Which sequence correctly traces a nervous response? Trace the stimulus, coordination pathway and negative-feedback response in order. Keep the named system boundary fixed.
Why are reflex actions useful? Trace the stimulus, coordination pathway and negative-feedback response in order. Choose the claim with the strongest scientific support.
Answer all questions to submit.
Next step personalized recommendations
Continue learning
Move forward only after this module is stable.
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