Biology GCSE Edexcel: The Nervous
System
What is a stimulus? - correct answer A change in the environment to which an
organism responds to.
What is a response? - correct answer A change in behaviour in response to a
stimulus.
What is the central nervous system (CNS) made of? - correct answer The brain
and the spinal cord.
What makes up the nervous system? - correct answer The brain and spinal
cord (for the CNS) and trillions of nerve cells called neurones.
What is the nervous system for? - correct answer It is an organ system that
allows allows your body to communicate, using electrical signals called impulses.
What is a sense organ? Give an example. - correct answer An organ that
contains receptor cells to detect stimuli. E.g. eyes, ears, skin.
How does the body create a response to a stimulus? - correct answer
Receptor cells in a sense organ detect a stimulus, they create impulses which usually travels to the brain.
The brain then processes this information and can send impulses to other parts of the body to cause a
response.
What are different steps to get from a stimulus to a response for a reflex action? - correct answer
Stimulus ---> Sensory receptor ---> Sensory neurone ---> Relay neurone ---> Motor neurone ---> Effector
---> Response
