-reflexes: automatic responses to changes (stimuli) inside or outside of the body, that help maintain homeostasis
-reflexes control heart rate, blood pressure, etc. and carry out automatic responses such as vomiting, sneezing, swallowing, etc.
-patellar (knee-jerk) reflex=simple reflex
-withdrawal reflex:Occurs in response to touching something painful (or laying a hand on a hot stove)
-involves sensory neurons, interneurons, and motor neurons
-sensory receptors send pain messages along sensory neurons to the spinal cord
-sensory neurons send impulses to interneurons, where information is coordinated
-interneurons issue motor commands to motor neurons
-motor signals are sent to flexor muscles to contract