Biology / Unit 12 Bio 2853 short lesson, about 20 seconds
The Spinal Reflex Arc
Captions available
The idea
A spinal reflex arc produces a fast, unconscious motor response through as few as one synapse between a sensory and a motor neuron, without the brain's involvement.
In practice
The knee-jerk reflex a doctor tests runs through a single synapse in the spinal cord.
Where people slip
A reflex can still send information to the brain afterward, through interneurons, though the response does not wait for it.
Your place on the trail
Every lesson rests on earlier ones and opens later ones. Tap any to jump.
Something wrong in this lesson? Flag it · Sources for Biology