Key learning points

1. The human body has a nervous system that enables us to sense and respond quickly to changes outside and inside the body.
2. Examples of stimulus (e.g. increase in temperature) and response (e.g. sweating).
3. The structures that make up the central nervous system (CNS) and peripheral nervous system (PNS).
4. Receptors detect stimuli; they can be single cells (e.g. in the skin) or groups of cells in sense organs (e.g. the eye).
5. Sensory neurones join receptors to the CNS; motor neurones join the CNS to effectors that carry out the response.

Keywords

• Nervous system - Detects and coordinates a response to changes in internal or external environment.

• Receptor - Senses a change in the environment, such as a change in light or temperature.

• Stimulus - The change in the environment, such as a sound, touch or light.

• Neurone - A nerve cell which transmits electrical impulses between different parts of the body.

• Effector - A muscle or gland which carries out a response.

Common misconception