What are the differences between reflex (involuntary) actions, and voluntary actions in terms of the way nerve impulses are transmitted through the neurones?
For instance, i know that in a reflex action, say, a prick of the needle on your hand, will stimulate the nerve endings in the skin. Then, nerve impulses are produced, and nerve impulses travel along the sensory neurone to the spinal cord. In the spinal cord, the nerve impulses are transmitted first across a synapse to the relay neurone, and then across another synapse to the motor neurone. At the same time, nerve impulses are transmitted to the brain. Nerve impulses leave the spinal cord long the motor neurone to the effector, and the effector takes action. So i end up moving first before i feel the pain in my hand.
But in what ways is it different in a voluntary action?
I know that there are some relay neurones that lie parallel to the length of the spinal cord. Why is it different from relay neurones that lie in the middle of the spinal cord in the grey matter?
Please tell me how is reflex action different from voluntary action in terms of the way chemical signals travel.
Thanks.
sorry it's electrical signals
In both reflex (involuntary) and voluntary actions, nerve impulses are transmitted through neurons to coordinate a response. However, there are some differences in the way these actions occur and how nerve impulses travel through neurons.
In a reflex action, such as pulling your hand away from a prick, the process begins with stimulation of the nerve endings in the skin. This stimulates sensory neurons, which transmit nerve impulses along their axons to the spinal cord. Along the way, the impulses pass through synapses, which are junctions between neurons. They first cross a synapse to relay neurons, which are located within the spinal cord. Then, the impulses cross another synapse to motor neurons, which transmit the signals to the effector, such as muscles, causing a rapid involuntary response. Simultaneously, nerve impulses are also transmitted to the brain, allowing you to become aware of the sensation.
In contrast, voluntary actions involve a more complex pathway. When you consciously decide to move, the nerve impulses start in the brain and travel through the motor neurons. The impulses travel down the spinal cord and synapse with motor neurons located in the ventral horn of the gray matter. These motor neurons then transmit the signals to the effector, resulting in the desired movement. Unlike reflex actions, voluntary actions involve conscious decision-making in the brain.
Regarding the relay neurons (also known as interneurons), they can be found throughout the nervous system. In the spinal cord, there are relay neurons both in the gray matter (central portion) and along the length of the cord (white matter). The relay neurons in the gray matter are involved in processing reflex arcs, allowing quick involuntary responses. The relay neurons in the white matter serve as connectors, transmitting signals between different parts of the spinal cord, brain, and peripheral nervous system.
In terms of how chemical signals travel, both reflex and voluntary actions rely on the transmission of nerve impulses, which are electrical signals. These impulses travel along the length of the axons of neurons. When the impulses reach the end of an axon, they trigger the release of chemical neurotransmitters, which cross the synapse to transmit the signals to the next neuron in the pathway. This sequence of electrical and chemical signals allows for the communication and coordination of actions throughout the nervous system.
In summary, reflex actions are rapid involuntary responses that start with stimulation in the periphery and involve a simple pathway within the spinal cord. Voluntary actions, on the other hand, are conscious decisions that begin in the brain and involve a more complex pathway throughout the nervous system. Both reflex and voluntary actions rely on the transmission of nerve impulses and the release of neurotransmitters at synapses to coordinate a response.