Simple Reflex Arc Flashcards
All 6 cards in this deck
What are the steps of a reflex arc, from stimulus to response?
e.g. touching a hot object and pulling your hand away- A receptor detects the stimulus — heat receptor in the skin
- A sensory neurone transmits the impulse to a relay neurone in the spinal cord (CNS), then to a motor neurone
- The motor neurone transmits the impulse to the effector, which produces the response — arm muscle contracts and the hand is pulled away
What is the role of sensory neurones?
They transmit electrical impulses from receptors (sense organs) to the CNS (brain, spinal cord or relay neurone).
Why is a reflex action faster than a voluntary response?
The impulse bypasses the conscious parts of the brain, passing through the spinal cord with fewer neurones and synapses.
What does it mean to say a reflex action is involuntary?
It is automatic — the response happens without conscious thought.
Why are reflexes useful?
They protect the body: the response is fast and needs no conscious thought, so there is less chance of injury.
What is a reflex arc?
The pathway that impulses take in a reflex, from the receptor to the effector.