Reflex Arc

by Jason Amores Sumpter
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We've all experienced that moment of the doctor's office, where they tap our knee and our leg just shoots out completely in voluntarily. This is an example of a reflects. These are neural pathways that are going to control involuntary, instantaneous movements to some type of stimulus. Often you'll hear this referred to as a reflex arc. Now the sensory neurons will actually carry information from the stimulus into the dorsal side of the spine. So here we have the dorsal side. This is the ventral side me. Pop my head out of the way so you can see what I've written. Ventral dorsal basically think dorsal like the thin, which is on the back of dolphins. So the sensory neuron is going to carry information towards the spine, and it's going to enter the dorsal side, and its cell body will be part of that dorsal root ganglion. We talked about a little while ago, and it's either going Thio synapse directly on a motor neuron or a new Interneuron that will, in turn, synapse on a motor neuron. So basically some type of stimulus is going to, uh, signal it, and it's going to intern signal either The Interneuron or Motor Neuron. In this case, we have an Interneuron right here before the motor neuron, and it's essentially going thio downstream. Result in the motor neuron sending a signal to a muscle and causing some type of movement in response. So motor neurons will leave the ventral side of the spine, as you can see, and they'll synapse on a muscle right neuromuscular junction to create some type of movement. The basic outcome of all this is, uh, you know, a very fast response to a potentially damaging stimulus. This is your body's way of protecting itself. And what's important to note is that none of this involves the brain. It does go into the spine, so it does involve the central nervous system. But no processing occurs in the brain with these reflects arcs. So here, in our example, you can see this guy's touching a hot flame, which is not a good idea. Don't recommend it, and that's going to cause a reflex arc, which will result in him pulling his hand away from the flame very quickly. You know, this is like if you step on a sharp object, you just shoot your foot up before you even have a chance to realize what happened. And again, these reflex arcs are just very simple neural pathways that allow free, quick response to some type of stimulus, generally a stimulus that signals some type of potential damage or injury. So with that, let's flip the page.