The Nervous System

This lesson covers the structure and function of the nervous system as required by the Edexcel GCSE Combined Science specification (1SC0). You need to understand the components of the nervous system, the types of neurones, how stimuli are detected and how the body produces a response.

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Why Do We Need a Nervous System?

The environment around us is constantly changing. Organisms need to detect changes and respond to them in order to survive. The nervous system allows the body to:

• Detect stimuli (changes in the environment).
• Process information and make decisions.
• Coordinate rapid responses.

The nervous system uses electrical impulses to transmit information, making responses very fast (typically occurring in milliseconds).

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Components of the Nervous System

The human nervous system consists of two main parts:

1. Central Nervous System (CNS)

The CNS is made up of the brain and the spinal cord. It acts as the coordination centre — it receives information from receptors, processes it and sends instructions to effectors.

2. Peripheral Nervous System (PNS)