AQA · GCSE · Combined Science
Course version: 8464 · Version from Sept 2018
Cells called receptors, which detect stimuli (changes in the environment)
Full specification wording
Homeostasis: cells called receptors, which detect stimuli (changes in the environment)
Receptors are specialised cells that detect stimuli, which are changes in the environment.
Checked against the AQA 8464 specification (opens in a new tab) on .
- Point 9 of 11
- 2 key terms
Study notes
From the checked teaching notes for this specification point.
The idea
Receptors are specialised cells that detect stimuli, which are changes in the environment. A stimulus can be external, such as light intensity, or internal, such as a fall in blood glucose concentration. Each receptor is adapted to detect one particular type of stimulus: receptors in the eye respond to light, and receptors in the skin respond to temperature or touch. Detection works because the stimulus changes the receptor cell. In the nervous system, this generates electrical impulses sent along a neurone. In the endocrine system, such as the pancreas detecting glucose, it triggers hormone release. A useful method is to name the stimulus and the receptor that detects it.
What earns the marks
- Receptors are cells (or groups of cells) that detect stimuli.
- A stimulus is a change in the environment, which may be internal or external.
- Different receptors detect different stimuli, for example receptors in the eye detect light and receptors in the skin detect temperature.
- In nervous responses, detection involves the receptor generating electrical impulses that travel along neurones to a coordination centre.
- In chemical responses, receptors such as those in the pancreas detect changes in blood chemistry and trigger the release of hormones.
Common mistakes and how to put them right
Saying receptors detect 'the environment' without identifying a stimulus.
Put it right by naming the specific change, such as a rise in temperature.
Confusing receptors with effectors.
Put it right: Receptors detect stimuli, whereas effectors (muscles or glands) bring about responses.
Assuming all receptors send electrical impulses.
Put it right by noting that some, like those in the pancreas, respond to chemical changes by releasing hormones.
Exam tips
- Use the definition chain 'stimulus → receptor → coordination centre → effector → response' to organise answers about nervous control systems.
- Link each receptor to the specific stimulus it detects rather than writing a general statement about detecting change.
Try the lesson
The start of the Homeostasis: cells called receptors, which detect stimuli (changes in the environment) lesson, made from checked teaching notes for this specification point.
Have a go first
What name is given to the cells that detect changes in the environment?
Listen
Receptors are specialised cells that detect stimuli, which are changes in the environment. A stimulus can be external, such as light intensity, or internal, such as a fall in blood glucose concentration. Each receptor is adapted to detect one particular type of stimulus: receptors in the eye respond to light, and receptors in the skin respond to temperature or touch. Detection works because the stimulus changes the receptor cell. In the nervous system, this generates electrical impulses sent along a neurone. In the endocrine system, such as the pancreas detecting glucose, it triggers hormone release. A useful method is to name the stimulus and the receptor that detects it. A strong answer earns marks for these points. Receptors are cells (or groups of cells) that detect stimuli. A stimulus is a change in the environment, which may be internal or external. Different receptors detect different stimuli, for example receptors in the eye detect light and receptors in the skin detect temperature. In nervous responses, detection involves the receptor generating electrical impulses that travel along neurones to a coordination centre. A common slip: Saying receptors detect 'the environment' without identifying a stimulus. Instead, naming the specific change, such as a rise in temperature. Exam tip: Use the definition chain 'stimulus → receptor → coordination centre → effector → response' to organise answers about nervous control systems.
See it
Key words
Say what each word means before you turn the card.
Receptors
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Stimulus
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See every definition
- Receptors
- Cells that detect stimuli, which are changes in the environment.
- Stimulus
- A change in the environment, which may be internal or external.
Label the diagram
Some boxes have lost their names. Pick the right name for each number.
1Box 1
2Box 2
3Box 3
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