This deep dive covers The Reflex Arc Pathway within Reflex Arc for GCSE Biology. Topic 3: Reflex Arc It is section 4 of 15 in this topic. Use this deep dive to connect the idea to the wider topic before moving on to questions and flashcards.
The Reflex Arc Pathway
The reflex arc pathway is the sequence of events that occurs when a stimulus triggers a reflex. It consists of:
- Receptor: A specialised cell (or nerve ending) that detects a stimulus such as pain, pressure, light, or heat.
- Sensory neurone: Carries the electrical impulse from the receptor to the spinal cord.
- Relay neurone: Located within the spinal cord; connects the sensory neurone to the motor neurone and coordinates the reflex response within the CNS.
- Motor neurone: Carries the impulse from the spinal cord back out to the effector.
- Effector: A muscle or gland that responds — for example, a muscle contracts to withdraw from the stimulus.
Practice questions for Reflex Arc
Which word best describes a reflex action?
State the correct order of the reflex arc pathway from stimulus to response. Name each component.
Quick recall flashcards
What is the reflex arc pathway?
Stimulus → Receptor → Sensory neurone → Relay neurone (in spinal cord) → Motor neurone → Effector → Response.
What is a reflex action?
A reflex is a rapid, automatic response to a stimulus that does not involve conscious thought. Reflexes protect the body from harm.