Why is a spinal reflex more rapid than a voluntary movement?

Answer 1

Because it doesn't have to travel as far. Voluntary movements originate in the brain. Reflex movements originate in the spinal cord.

Evolutionarily, it's a safety thing. If you touch something harmful, you don't want to have to think about it. When you touch a hot stove, for example, you pull back before you realize that you've been burned.

Answer 2

In spinal reflexes, the sensory neurons synapse in the spinal cord rather than go through the brain directly. This lets the reflex action to occur rapidly. Voluntary movement is controlled by the substantia nigra which is located in the midbrain region which is why I think it'd be slower than the spinal reflex where the neurons just synapse in the spinal cord.

Answer 3

ill give you your answer short and sweet. Your periphery nervous system recieves a stimuli which sends a message to the spinal cord which sends a message to the brain and then back to produce a behavior. However, a spinal reflex only goes from the periphery to the spin and back. Shorter distance, means shorter time. V= velocity d= distance t=time, using the equationg V=d/t you can not only prove its faster by observation, but by mathematical law. For instance, say the impulse travels through the body at 10 k/s and has to go a distance (through the bodies nerves) of .1 k we can solve for "t" 10k/s=.1k/t... t=(.1)(10)..."t=1 second" now lets shorten the distance to see if it shortens the time 10k/s=.01/t...t=(.01)(10)..."t=.1 second" So, since point one second is less than one second we can conclude that the shorter distance inevitably results in less time of travel as long as the velocity stays the same. which it does.

Answer 4

That's because reflexes depend solely on the reflex arc, which consists of:
-A receptor, which on most cases is a neuron's dendrite.
- A sensitive neuron,that sends the info directly to the posterior horn. It may synapse directly with a motor neuron (monosynaptic reflexes) or with one or many interneurons (polysynaptic reflexes) that will ultimately synapse with the motorneuron. The interneuron may also inhibit the motor neuron of the antagonist muscle for the reflex
- A motor neuron, that sends a signal to the muscle that will enter into action.