Chapter 34.4, Problem 11SAQ

Summary Introduction

To draw:

A simple circuit that includes a sensory neuron that synapses with a motor neuron to produce a reflex. Also indicate where in the nervous system this synapse is found.

Introduction:

A response to a stimulus is usually produced by the transmission of signals to the brain where it is processed and sent to the motor neurons of the effector organ or muscle.

But sometimes a fast response or action is generated by simple reflex circuits. The sensory signals passing through simple reflex circuits do not pass through the brain. These circuits connect sensory neurons that receive the signals directly to the motor neurons that provide response. Knee-jerk extension reflex is an example of simple reflex circuit.