lesson
A response follows a pathway
1 · Learn
A reflex response involves receptors, neurones and an effector, with signals passing through a coordinated pathway. Receptors detect a stimulus; effectors such as muscles or glands produce a response. Synapses connect neurones through chemical signalling.
A reflex can occur without a conscious decision first, but information can still reach the brain. Avoid describing every response as an identical pathway or implying the nervous system is a single wire.
2 · Worked example
In a simplified withdrawal reflex, detecting a harmful stimulus can lead to muscle contraction through the reflex pathway before a conscious decision is made.
3 · Your turn
What is the role of an effector?
Check your answer
To produce the response, such as a muscle contracting or a gland secreting.
4 · Apply your learning
Sequence a supplied pathway diagram; do not create painful or hazardous stimuli to demonstrate it.
Adult guidance and safety
Use supplied evidence and approved models. Practical work needs qualified supervision, risk assessment and suitable equipment. No independent chemical, mains-electricity, radiation or biological-culture experiments. Human biology is general education, not personal medical advice; do not request intimate or health disclosures.
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Check a calculation · Year 5 onward
Use this only when your teacher or adult allows a calculator for the task. Show your thinking first. It does not replace mental or written arithmetic and does not mark your lesson answer.
Powers, roots and trigonometry · Year 7 onward
Use only when the task allows a calculator. Choose one operation at a time and record your working. Trigonometry here always uses degrees (DEG), not radians. Inverse sine, cosine and tangent return an angle, not a reciprocal. Keep exact fractions and π in answers when requested.
Approximate numerical results use up to 12 significant digits. Inverse sine returns −90° to 90°, inverse cosine 0° to 180°, and inverse tangent −90° to 90°; these are principal values, not every possible solution of a trigonometric equation.
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