What is the Spinal Reflex Arc?

Answer 1

A spinal reflex is an automatic, rapid response to a stimulus. The action is involuntary and occurs without any involvement of thought or the brain. In humans, this action occurs through a neural pathway called the reflex arc. To allow reflexes to occur very quickly, signals come directly from motor neurons in the spine, instead of being delayed by going through the brain.

The arc works as follows:

1. A receptor at the point of stimulus relays the message that there is an adverse stimulus to a sensory neuron

2. The sensory neuron carries the message from the receptor at the point of the stimulus to the spinal cord (part of the central nervous system)

3. In the spinal cord, a relay neuron, or inter-neuron, carries the message from the sensory neuron to a motor neuron

4. The motor neuron then carries the message to the appropriate effector, at which point, the reflex occurs.

After this spinal reflex occurs, sensory neurons send messages to the brain. The brain then relays this information and the messages are consciously interpreted. It is only at this point that you will begin to feel pain.

Though this seems like a complicated process, spinal reflexes occur in under one second. Within that same second, the brain will consciously interpret the information and the person will feel pain.