Chapter 13, Problem 1CC

List the general steps of a reflex pathway, including the anatomical structures in the nervous system that correspond to each step.

Summary Introduction

To determine: The general steps that involved in a reflex pathway along with the anatomical structures that are involved at each step.

Introduction: Reflex actions are generated involuntarily in the body against stimuli. Information about such actions is processed and accordingly the response action is done by the body in very short time. Reflex actions are generally seen in situations involving negative feedback.

Answer to Problem 1CC

Pictorial representation: Fig. 1 represents the general steps involved in a reflex pathway.

Fig. 1: Steps along with the organs involved in a reflex pathway

Explanation of Solution

In a reflex pathway different steps are involved for conduction of signals. Different anatomical structures are involved at each step.

• Step 1: Receiving of signals (stimulus) and activation of receptors

  Signals for different stimuli are received by the sensory receptors that are present on the different sensory organs of the body.

• Step 2: Conduction of input signals

  Signals received by the receptors are passed on to the sensory neurons. These signals pass through the afferent pathway towards the spinal cord.

• Step 3: Signal integration

  The incoming signal in case of reflex action is integrated and processed at the spinal cord itself which serves as integrating centre. Here the signals for the needed response is generated and passed on towards the target site. From the spinal cord, signal is also transferred to the brain for further processing.

• Step 4: Conduction of output signals

  Response signals generated in at the integration centre are sent back to the target site through the efferent neurons. These signals make the target organs to take the necessary action.

• Step 5: Response

  Response for the stimuli is done by the target organ. Signals for the response travel through the efferent neurons to the target site and the required action is performed.

It is important to note that in reflex pathway, although the incoming stimuli signals are transferred to the brain for complete processing but the response signal for the incoming stimuli is generated at the spinal cord itself for quick response action.