This chapter 5 is a little bit different than the 6th edition so we work only with the 7th edition now because as of August 31st that transition time has passed.

So this chapter revolves around the nervous, muscular and skeletal systems.

You can see your learning objectives there but it's basically going through the structures, types of really just the main nuts and bolts of each one of those systems.

So 45 slides of very important material that will be very demanding on you to remember but also very important for you to understand as you're going through and taking your tests.

So again, as we go through, there's your learning objectives one more time.

So let's get into the human movement system.

Now the human movement system is basically, it's a bunch of components that are put together and structures that work together so that we can get you to take a step forward, to jump up in the air, to basically do whatever kind of movement you're talking about.

Now again, we talked about it in the intro slide but the nervous system, skeletal system, muscular system, they're all going to be what makes up the human movement system and they all work together in a really efficient and effective manner if you train your body to be in that way.

So again, if you don't though, like it says here, if you have one component that doesn't function correctly, it's going to move down what we would call the kinetic chain or all those links that you would see on the right-hand side and all of those links, if one of them starts to either break down, move in a different direction, or basically just has a faulty pattern to it, it'll affect the whole system.

So if something is going on in the ankles, that could affect anything all the way up into the cervical spine.

Hips, we know that hips really work in conjunction with the lumbar spine.

So you can see how if one is affected, the other could be as well and we always think about one above, one below, but at the same time, depending upon the situation, it could be more than one checkpoint above or below.

So just kind of something to think about, basically, again, human movement system is all about efficient movement of everything working together, but if that kinetic chain is broken down, then we're going to have to find a way to correct those imbalances and asymmetries so that we can get you to be functioning correctly.

So the nervous system, again, all based off of nerves, those neurons that we would talk about, like it says here, it's one of the main organ systems of the body and the central nervous system, if we want to be more specific, we're talking about the brain and the spinal cord, whereas the peripheral nervous system, the PNS, that is your peripheral nerves.

That's going to be what's more getting into the limbs outward.

So without neurons, we don't have that functioning of the nervous system.

We don't have that ability to make basically an electrical current turn into a chemical signal to then create a firing of a muscle.

So it's very, very important.

As we go through here, a couple of terms that we really want to pay attention to are these bottom ones down here, afferent or afferent and efferent or efferent, and both of those are very important because they are the specific signaling that occurs as we move through a specific muscle contraction or just in general.

The afferent information that's basically processed, it's a sensory information.

It could be, just say that you take your finger and touch it down on an oven.

When you do that, that basically creates a signal sent to the brain that, oh man, this is hot.

The brain processes that through inner neurons and the workings up there, and then basically sends an efferent signal to say, hey, you need to move your hand because you're going to get burnt, dummy, and then that's how it would basically work.

You sense it, process it, send the signal to do whatever movement or function that you're trying to do, and that's how that pathway kind of works.

So that's part of that whole nervous system functioning.

Here's your nerve, your neuron.

This is your true neuron.

Make sure that you understand each component.

You have your nucleus, and surrounding that nucleus, you do have the cell body.

That cell body is what has the attachments that come off of it, which we call dendrites.

Dendrites meaning that they are the transfer connections between one neuron and another.

Then you also have a terminal point, which is your axon.

That axon has basically the tail.

That tail can end in what we would call synaptic terminals.

Now at the ends of those synaptic terminals is where typically you would have those connection points to the sarcolema, or basically the muscle.

That's where, like we said in the previous slide, the electrical current turns into the chemical component at that point, and that's where muscle contraction can start happening.

Now, like other things, there are four primary ingredients that are needed for nervous systems to fire, sodium, potassium, magnesium, and you also need water.

So if you're dehydrated, that can also have an improper function for you.

So again, just kind of paying attention to the structure points for this, making sure you know what an axon is, what a dendrite is, and that'll help you to be able to kind of understand the main parts that we're looking at.

For the central nervous system, we said it's divided into that brain and spinal cord.

The peripheral nervous system, the PNS, that is the point where you have everything going out to the periphery.

So you have 12 cranial nerves, excuse me, 31 pairs of spinal nerves, and you also have sensory receptors that will detect changes in touch, changes in pressure, changes in tension so that you can have those sensory information sent back afferently to then relay information efferently to move as we need.

Then I spoke a couple slides ago about interneurons.

They are within the spinal cord, and basically when you look at it, it is a function where once you have that afferent signal, so follow the blue line.

The blue line you'll see is that sensory nerve.

It's sent into what we would call the horns of the spinal cord, and you'll see the blue part there.

It goes into the interneuron.

There's detection agencies there, and at that point, that interneuron processes, takes the process information and sends it out efferently to move your bicep, move your forearm to then be able to take your finger off of whatever the stimulus was of it.

So that's basically how you break down that whole process, afferent, efferent, and that's what we would call the reflex arc, and that's that whole process that we would talk about right down here on the bottom with the peripheral nerves and the interneurons and how they work all together to provide a reflex to move in the proper manner.

Also for the nervous system, we talked about touch and pressure.

We have mechanoreceptors for that.

Now mechanoreceptors are really big on, again, working with sensory nerves to be able to provide us with proper information to then either move correctly, react correctly, sit down, stand up, take a sip out of the water fountain, whatever it may be.

Again, mechanical force, nociceptors, which are for pain, chemoreceptors, we're going to be talking more about smell and taste, and then photoceptors for vision.

So all of those there, again, working within our senses, and all of them have a specific receptor that will be able to dictate what you sense to what you react to.

So as you look at the central nervous system, and you see on the right there the complete breakdown, your true nervous system is broke down to central and peripheral nervous systems.

The central nervous system is its own entity.

The peripheral system, you can see here, it gets broken down into those sensory nerves we talked about, and also the motor neurons for movement.

Now movement-based, we have two types, somatic and autonomic.

Autonomic, I'll start with that one first, even though it's the second one listed.

Autonomic is going to be the one that is really automatic.

You don't require, it's not voluntary, you don't tell it to.

It just naturally does it on its own.

But if you are stimulated in a certain way, whether relaxatively or excitedly, then basically you will end up with a change.

Now if you go down a little bit more onto the last two bullet points here, you'll see the autonomic nervous system is broken down into two other components there, which we call sympathetic and parasympathetic nervous systems.

The sympathetic nervous system, it reacts more to the heightened state, more fight or flight, where parasympathetic works with, again, more relaxative portions of everything.

On the inverse side of it, the somatic nervous system, we're talking here more about the basics to our movement, our motor movement.

How our nerves will provide that stimulus to move skeletal muscle because we tell it to.

If you need to reach up in a cupboard and reach up and grab a can of green beans, then you have to be able to tell your body the proper mechanism to be able to do that.

So you're not physically telling yourself, hey, now make sure you get up onto your tip toe.

You're not doing it in that manner, but you understand that your body is telling you what you need to do and your body is reacting in that way, but it has to be you that makes that conscious effort and movement.

So again, we talked about that sensory function with all five senses.

There's also something called proprioception, or basically just understanding where you are in your environment, where your body parts are located.

And that works a lot with balance and coordination, a little bit of agility.

It also works around your posture.

So with proper posture comes proper detecting agents of where you are in space, and that's what proprioception is really more about.

Also within your nervous system, you have what we call integrated functioning, and that's being able to basically take in information, analyze it, interpret it, and then send out the proper decision-making signal to then act accordingly.

That's really what it comes down to.

And then your motor function, again, is your true movement that we would talk about.

So again, the sensory function, more afferent, proprioception, integrated functioning.

That again is the afferent to the inner neuron, sensing, decision-making, and then the motor function is more of your output or your efferent, efferent pathway.

And that's really the main way that we go through each process.

And then once your motor function occurs, the sensory function may have to react in another manner so that we can then react in another way to do another task that we have in front of us.

When you're multitasking, you're always going through sensory function, motor function, sensory function, motor function, and everything in between, so you're doing a lot of decision-making.

So if you're a great multitasker and you're doing it second nature, then you're going through all four of these steps very handily without really worrying too much about it.

Definitely something that's going to be on your test, pay attention to it for sure, is the difference between what we call a muscle spindle and a Golgi tendon body or Golgi tendon organ.

We'll hit on the muscle spindle first.

Now, don't make it more difficult on yourself.

Make sure for your sake, muscle spindles are found in the muscle.

Their job is to detect changes in length or stretch and the rate that that happens.

So when we have muscle spindles, we're always, your body is basically preserving itself, meaning that when it's part of your sensory system, so when the muscle gets stretched in a manner, so, you know, and I know it's kind of far fetched here, but think about a person, a male in particular, and they slip a little bit and they get into that split position that, you know, males typically are not as flexible as females, but in this sense, a male who is not very flexible and he gets into that, you know, that position of a split.

Now he is going to feel that very handily and his muscle spindles are going to try to do whatever they can to avoid excessive stretching.

But when you, if you slip and fall too much, that's why, you know, you'll get injuries because muscle spindles weren't able to preserve and basically avoid that from happening.

Another way to kind of talk about a muscle spindle, and this goes along with what we call the stretch reflex.

If you were to have somebody lay down on the ground, have them put one leg straight, so just say the left leg straight, you take their right leg and you do a hamstring stretch.

So if they're lying on their back, you're going to try to bring the toes up into the air and try to flex the hip.

Well, as you start going up into that stretch, when a person hits that kind of max limit for themselves, what you're going to feel if you do it slow enough is when you feel that end range of motion, right when you hit that end range of motion for that person, you might feel the leg involuntarily kick back on you.

And that's the muscle spindle basically engaging to say, I'm sensing I don't like this length.

I've, I'm processing, I've processed it already and I've sent a signal to say, don't go anymore.

So what you do, you go to that point and then once it kicks back a little bit, you hold it right there and you stretch a person.

And what you can then tell them to do is, Hey, I want you to contract.

So push back against me.

Then you let it down, relax for a second, then do it again.

What you'll see is that the muscle spindle has been overpowered a little bit and it's going to be able to release a little bit more tension and you can stretch the person a little bit for farther.

Now that is the true advent of, of your, uh, PNF, um, uh, proprioceptive neuromuscular facilitation.

And that's a different type of stretch that we can work with and it helps with end range of motion.

Very, very important for that.

So again, we talked about the muscle spindle.

Let's talk about the Golgi tendon organ or the GTO.

Now again, like the muscle spindle, very, very simplistic here.

We are going to say that the Golgi tendon organ is found in the tendon, okay?

Its job is really to be, it's very sensitive to tension and that rate of tension.

So when we talk about, you know, tension, we're talking about like if you have that issue where you're, you know, feel like there's pressure being put down on a, on a 10 or there's a pull on that tendon, it'll feel that.

And when it feels that, it'll end up having a, again, a reverse effect where it's going to try to stop you from going any farther than where you are.

So if there's a lot of tension on that, you know, that muscle that provide, and then the

Golgi tendon receptors sense that, they'll send out a signal to the brain saying, stop what you're doing.

Um, uh, another example of that would be as if you get down into a squat, all right, and you go to push up out of the squat.

Well, you know that there's a lot of compression, there's a lot of tension being put onto the joint in particular being put onto the skeletal muscle of the quads.

So the body will shut you down if you're providing too much tension because maybe you're trying to do a one rep max or something like that.

So hopefully you have the pins set up in the rack so that all you do is just lower yourself back down to those pins and walk out without an injury.

Okay?

So again, you can overpower your muscle spindles and your Golgi tendon organs, but usually when you overpower them, it leads to injury on the back end of everything.

Okay?

So the other thing too, a couple more, you know, one more aspect here of mechanoreceptors, we're talking about joint receptors.

You're talking about nerve endings that you find inside of the joint capsule.

Um, they're found all around, you know, on the ligament components on the capsules themselves.