 Hey everybody, Dr. O here, in this video I want to talk about reflexes. So when you think of reflexes, you generally do think of a rapid automatic pre-program response to a stimulus and that's absolutely what they are. We'll look at the steps in the reflex arc and how they work in this video. In a future video, we'll talk about different types of reflexes, like the withdrawal reflex that can pull you away from dangerous stimuli, the cross-extensor reflex that keeps you from falling over, these types of things, but I just want to talk about them in general. The reflexes, we'll talk about the types of reflexes later as well as far as some are innate, you're born with them, others have to be acquired, but why are reflexes so important? The way I like to look at it is reflexes buy your brain time to make good conscious decisions. So when they reflex, like if you touch this hot stove, you don't want to wait for your nervous system to send that signal all the way your brain, for your brain to perceive it as hot, say, you know, that's probably not a good idea, like, you know, my skin is melting off, I should probably do something about this and then remove the hand. A reflex will pull your hand off of this hot stove before your conscious mind even knows it was on there, so it buys you time to make smart decisions. Now as humans, we should use our conscious minds to number one, know we shouldn't have touched it in the first place, number two, hopefully never do it again, right? So you still need our higher order functions, but the reflexes will buy you the time to make those better long-term decisions. Another thing about reflexes, I think that, you know, it's, what do we define as a reflex? Like, you know, the knee jerk reflex and withdrawal reflex, these are typical reflexes, no one would argue that, but I would argue that the other thing about reflexes is you can learn, this is the idea of muscle memory, you can learn things so well that they almost become reflexes. So it's not a true reflex, but the nice thing about that is having more and more things kind of pre-programmed into your brain is it decreases how much conscious energy it takes to do something. So think about, like, walking. You basically just get up and you just levitate towards your destination and you just end up there, right? You're not thinking left foot, right foot, left foot, right foot. You're not thinking about how you're using the rest of your body to balance you so you don't topple over. Think about reflex, you know, chewing, like, chewing's basically become a reflex. You just start chewing. You don't even think about it and think about all those complex things that are going on in your mind. Or think about anything that you've learned really well, that you've just kind of programmed. It happens all the time, like, my stepson asked me to help him with a tie and I don't know how to tie a tie unless I just put it on and do it, right? My hands remember how to tie a tie. I don't consciously remember how to do so. So I think that's kind of a neat way to look at it, too, is so we have these actual reflexes, then we have things we get so good at that they become these unconscious, you know, on some level kind of like a reflex. Same thing with athletics, you know, I've worked with tons of athletes and think about, like, my favorite example is always a baseball player hitting a baseball, like, it's been proven that you can't consciously make all the decisions you need to hit a baseball in time if it's, you know, 94, 95 on our fastball, but you just see the ball and hit the ball. So all that pre the pre program responses are in there. So it's almost like hitting a baseball becomes a reflex. Playing piano becomes a reflex. I just wanted to talk about this because to me it's kind of cool, but now let's talk about an actual reflex that no one would argue about. So here we see just an example of a pretty straightforward reflex called the withdrawal reflex or reflex. So this is going to be that automatic response that will that will buy you time to make better decisions. So this, this entire wired circuit here would be called a reflex arc. It starts with a peripheral receptor, then a sensory nerve, then the information is going to be processed at the level of spinal cord here for a spinal reflex, then a motor nerve and then your peripheral effectors. So those are going to be the parts. So step one, we have a stimulus. So in this case that, you know, their hand is on a painful stimulus that's going to activate that receptor, which is going to trigger step two, the activation of a sensory neuron. Step three is going to be information processing. So in a reflex situation like this, it's going to be just an immediate response. We have to withdraw from this painful stimulus. So that's going to be the first immediate response. But notice that white interneuron is also sending information up to the brain. So you can, you can make more conscious decisions about this as well. Step four, you've now triggered the motor neuron and then step five is going to be the effector is now going to do its job, which in this case is to withdraw from the painful stimulus. So this can happen in milliseconds, right? Your simplest reflexes can occur in 20 milliseconds. So in a very short period of time, your body has responded with this pre-program response. Okay, so that's what a reflex is. And this is a typical reflex arc. We'll come back and talk about the types of reflexes next. I hope this helps. Have a wonderful day. Be blessed.