Reflex actions are sudden responses. It is an involuntary action that does not involve thinking. For example, when we touch a hot object, we withdraw our hands immediately without thinking.
The sensory nerves that detect the heat are connected to the nerves that move the muscles of the hand. Such a connection of detecting the signal from the nerves (input) and responding to it quickly (output) is known as a reflex arc. Reflex arcs are formed in the spinal cord but the information is still sent to the brain. The brain doesn’t have a significant response to it.
Events that precede a stimulus in organisms.
- The first event begins with the receptor detecting a stimulus from a sensory organ. The stimulus could be in the form of pressure, temperature or chemicals.
- This is followed by the sensory neuron sending a signal to the relay neuron.
- The relay neuron then sends the signal to the motor neuron.
- The motor neuron sends a signal to the organ or a cell that acts to the stimuli, called the effector.
- Finally, the effector produces an instantaneous response, such as a knee-jerk reaction.
Check the video provided below for further reference.