Cambridge O Level Biology · Syllabus 5090 · Coordination and Control
Peripheral Nervous System
What is Peripheral Nervous System?
All the nerves outside the brain and the spinal cord. The peripheral nervous system carries impulses from receptors towards the central nervous system along sensory neurones, and from the central nervous system out to effectors along motor neurones.
This definition is part of the Coordination and Control chapter in Cambridge O Level Biology.
Common mistakes with Peripheral Nervous System
- Nerve or neurone? These are not synonyms and the exam distinguishes them. A neurone is a single nerve cell. A nerve is a bundle containing the fibres of many neurones, wrapped together in connective tissue. So the peripheral nervous system is made of nerves, and each nerve contains many neurones. Writing "a nerve carries an impulse to the CNS" is loose; "a sensory neurone carries an impulse to the CNS" is precise, and precise is what gets the mark.
Questions students ask about Peripheral Nervous System
What is the difference between a nerve and a neurone?
A neurone is a single nerve cell. A nerve is a bundle containing the fibres of many neurones. The peripheral nervous system is made of nerves, and each nerve contains many neurones.
Last reviewed Syllabus 2026-2028