A doctor explains to a patient that their body constantly monitors and adjusts internal conditions. The doctor describes two systems that the body uses to communicate and respond to changes: the nervous system and the endocrine system. Compare how the nervous system and the endocrine system communicate information around the body.
Written & reviewed by James Millett — Biology (Imperial College London), PGCE Science (University of Cambridge).
The human body must maintain a stable internal environment despite changes in external conditions. Two major communication systems help achieve this: the nervous system, which uses electrical impulses, and the endocrine system, which uses chemical messengers released into the blood.
Model answer (5 marks)
The nervous system uses electrical impulses (nerve impulses) that travel along neurons and nerves, whereas the endocrine system uses hormones that are released into the bloodstream.
Nerve impulses move rapidly along a single neuron or a short chain of neurons, so the nervous system can transmit signals almost instantly.
Hormones travel through the blood to reach target cells, which takes longer, so the endocrine system produces a slower response.
Because nerve impulses are brief and terminate quickly, the nervous system generates a short‑lived response.
Hormones can act on many cells over a longer period, giving the endocrine system a longer‑lasting effect.
Nerve impulses usually act on a specific effector such as a single muscle or gland, giving a localised response, whereas hormones can affect many target organs throughout the body, producing a widespread response.
Nerve impulses move rapidly along a single neuron or a short chain of neurons, so the nervous system can transmit signals almost instantly.
Hormones travel through the blood to reach target cells, which takes longer, so the endocrine system produces a slower response.
Because nerve impulses are brief and terminate quickly, the nervous system generates a short‑lived response.
Hormones can act on many cells over a longer period, giving the endocrine system a longer‑lasting effect.
Nerve impulses usually act on a specific effector such as a single muscle or gland, giving a localised response, whereas hormones can affect many target organs throughout the body, producing a widespread response.
Examiner tips
- Use the exact terms ‘electrical impulses’, ‘hormones’, ‘neurons’, ‘bloodstream’; show the contrast in speed, duration and scope of action.
- Structure answer in five clear points matching the mark scheme.
- Include the word ‘fast’ vs ‘slow’ and ‘short‑lived’ vs ‘long‑lasting’ to hit the key descriptors.
Common mistakes
- Confusing the speed of the two systems (e.g. saying endocrine is fast).
- Using vague language such as ‘fast’ without specifying the nervous system, or ‘slow’ without specifying endocrine.
- Failing to mention the route of signal (neurons vs bloodstream).
Mark scheme (5 marks)
- The nervous system uses electrical impulses / nerve impulses, whereas the endocrine system uses hormones / chemical messengers
- Nervous system signals travel along neurones / nerves, whereas endocrine system hormones travel in the bloodstream
- The nervous system produces a fast response, whereas the endocrine system produces a slower response
- The nervous system produces a short-lived / brief response, whereas the endocrine system produces a longer-lasting response
- The nervous system produces a localised / specific response (acts on a specific effector / muscle or gland), whereas the endocrine system can produce a widespread response (hormones travel throughout the body / act on target organs)
Key terms in this question
nervous system · endocrine system
Related
- All OCR A-Level Biology B — Advancing Biology (H422) revision notes →
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