-Kumudinee, Subject Matter Expert at Edumarz
Solution: Reflex actions are sudden and spontaneous. It happens involuntarily without thought process in response to the stimuli. For example, blinking of eyelashes when some dust enters eyes.
Events that precede a stimulus in an organism:
At the very first receptor detects the stimulus from a sensory organ. The stimulus could be temperature, pressure, aroma, sound etc.
Then the relay neuron transmits the signal to the motor neuron.
The motor neuron then sends a signal to the effector organs or cells that act to the stimulus.
Finally the instantaneous response is given by the effector organ or cells.
Here connections where signals are detected by nerves and response is given quickly are known as reflex arcs.
The reflex arm is formed in the spinal cord by motor neurons and the information is still sent to the brain but the brain doesn’t have a significant response to it.
This is why reflex actions are involuntary in nature.