Cambridge O Level Biology · Syllabus 5090 · Coordination and Control
Reflex Action
What is Reflex Action?
A rapid and automatic response to a stimulus. A reflex action begins without a conscious decision being made, which is why it can protect the body from damage faster than a deliberate movement could. The brain is usually informed shortly afterwards, but it does not have to act before the response begins.
This definition is part of the Coordination and Control chapter in Cambridge O Level Biology.
Questions students ask about Reflex Action
What is a reflex action?
A reflex action is a rapid and automatic response to a stimulus. The response begins without a conscious decision being made, which is why it can protect the body from harm faster than a deliberate movement could.
Last reviewed Syllabus 2026-2028