Question

A woman accidentally touched a hot pan without wearing a pair of mittens. On contact, she immediately yanks her hand away.
Select the CORRECT statement with respect to the above phenomenon.

• A. The signal received from the sensory organ is carried into the PNS.
• B. The efferent neuron receives the signal from the sensory organ.
• C. The impulse is transported via a dorsal nerve root to the spinal cord.
• D. The action is voluntary in nature which involves conscious effort and thought.

Answer 1

Answer: (C)

When a person comes in contact with an extremely hot object, he or she quickly remove themselves away from it. The entire process of response to a peripheral nervous stimulation, that occurs involuntarily, i.e., without conscious effort or thought and requires the involvment of a part of the central nervous system is called a reflex action. The reflex pathway comprises at least one afferent neuron (receptor) and one efferent (effector or excitor) neuron appropriately arranged in a series. The afferent neuron receives signal from a sensory organ and transmits the impulse via a dorsal nerve root into the CNS (at the level of spinal cord). The efferent nueuron then carries signals from CNS to the effector.