Reflex Actions

A reflex is a rapid and involuntary response to a stimulus, resulting from a simple signalling pathway called a reflex arc

  • Reflex actions do not involve the brain – instead sensory information is directly relayed to motor neurons within the spine 
  • This results in a faster response, but one that does not involve conscious thought or deliberation

Reflex actions are particularly beneficial in survival situations, when quick reactions are necessary to avoid permanent damage

  • A common example of a reflex action is the patellar reflex (‘knee jerk’ response) that occurs when the patellar tendon is tapped
  • The patellar reflex is a common test employed by doctors to determine the presence of spinal lesions 

Example of a Reflex Arc