Okay, so I'm gonna share first web browser as always if you have a question, please put it in the chat function.
So this is what canvas looks like for you guys again,
a few due dates that are coming up that I want you to be aware of,
what are the assignments page so ones that you have coming up again,
your discussion questions for the week you need one one of them has to answer these questions.
Nervous system, questions, part two. The other one has to be the things you found interesting are confusing week two. So those are two discussion questions or discussion posts for this week. You have a worksheet about different types of Gloria.
That's gonna be due April tenth,
which is Friday at midnight and then next week we have homework five,
which is do it our class time at ninety five,
second round of discussion questions as well as the new things you find.
Interesting post. And then there is a case study that I want, you guys to do, we would have done in class next week, but we don't meet as class time.
So instead we'll do it out of class and then the cranium, the worksheet. And then we will start chapter eight, which is our senses.
So we're getting to the mid mid and part here of chapter seven.
Okay,
so with that people have any questions about what is due this week,
or next week another reminder that Friday is good Friday so we won't be having a WebEx class you have that Leo works,
you do in your discussion boards but otherwise it won't be any work for Friday,
any questions people have about what is coming up.
Okay, I'm gonna switch gears and we're gonna jump into the PowerPoint here. Okay.
So,
when we talked about last time,
our reflexes,
and then the different parts of the brain into what different parts of the brain do as a reminder,
you need to know where you can find a picture for Lopes of the brain.
It should be pretty straightforward. Because again, those four loves match with the bone so we have the frontal lobe, and we have the parietal lobe on top the occipital open the back and the temporal lobe are temples. Not only do you know where those four Lopes are each of the functions?
What functions are assigned to each of those Lopes. So if you see a list of functions, you need to be able to tell me what load of the brain.
They would go for the deeper brain structures that we talked about the midbrain, the diencephalon brainstem, those sorts of structures you Jessie to know what they do.
So you don't need to know where they are on a on a visual map. You need to know which grouping they go into, but you don't need to know where they are on a visual map of the brain. You just need to know the function.
So, we're gonna jump into part four here and answer your question that we've been. We've been thinking about this for a while. So we've been thinking about why we need to protect neurons. What makes neurons.
So,
specialized,
remember neurons are the signaling cells in the brain there,
there's electrical cells,
and they go throughout the body in our central and our peripheral nervous system and neurons are special because they're their post.
My ptoduct neurons are delicate. They cannot reproduce anymore. So, they can't replicate, they can't fix themselves by making more neurons.
So, if you have a brain injury or a spinal cord injury, you're not gonna be able to repair that by filling the gap via mitosis in the same way that you would with skin neurons or also, especially because they have a very high energy demand.
So, if you're looking at the action potential, there's a lot going on there. There are a lot of enzymes or receptors working, and all of that takes energy.
So, the, the steps of the action potential, the voltage gated sodium channels in the multitude of potassium channels, they use the energy that's stored in those gradients right?
The high amount of sodium that needs to present outside the sound on the high minute potassium that's present inside the cell those gradients. But to set up those gradients that takes the sodium potassium pump which uses.
So, neurons use a lot of in fact, when you're taking an exam, or you're studying hard, an hour of intensive focus will burn the same amount of calories as running a mile.
And that's because your brain is using all that glucose to make to keep these gradients up.
And so neurons are post metallic,
they have high energy demand and so they're also very important functionally because we know all of our decisions,
all of our actions are controlled by the nervous system this is where we integrate all of our stimuli.
So they have an important job they use on energy, they can't pair themselves and all of that leads to the body spending a lot of energy, and a lot of structures to help protect these delicate cells. So we protect them in a few different ways.
We use bone to protect our central nervous system in the form of our skull around our brain and the vertebrae around our spinal cord. We also cover them in layers of membranes called, which we'll talk about early. They're bathed in a fluid.
This is called the cerebral spinal fluid in the fluid also provide some questioning. The other way that we've talked about already are the form that blood brain barrier with the Astra sites.
They have cushioning and supporting walls themselves are another way that we protect our nervous system. That we've already discussed, let's dive into a few of these other other ways of protecting our nervous system.
And the focus is really on the central nervous system. Because it is the integration center has the most, most important function compared to the peripheral nervous system.
So, we're gonna focus on how we protect this crucial, crucial part of our nervous system, our brain and our spinal cord.
So, we cover them all in the Ninja bones. We've talked about when we talked about the bone chapter, but are layers of membranes, that cover the central nervous system.
So, if you start with your Scout, the skin, that you're Scout, then you're gonna have a periosteum layer. Which separates the skin from the bone, and you'll go into that protective bone this case we're talking about the brain so we have our skull.
We have all those facial bones make up this call and then you have three layers of that. Your dura mater your arachnoid mater. So you need to know those three layers.
They make the acronym depth going from outside in dura layer and then under that is where you're gonna have our sub,
Daryl,
several recognized space,
or additional layers under all that is really going to have your your cerebral spinal fluid,
which is when we bathing the the brain.
So the, for the cerebral spinal fluid acts, as a cushion, it's continually made and then a region of the coronoid plexus, and it's made from blood and it's gonna take the blood and they're going to make it into this this fluid.
That's gonna go through the roof of the ventricles. Remember the ventricles are these holes that you have in the middle of your brain to the cerebral spinal fluid is going to go from the roof of the ventricles and circulate through the ventricles.
And down to the spinal cord, and so if you were to look at the brain, it would appear like, it was just gently floating in fluid. And this again is a cushioning. So if you stop short and you hit your head on something, for example.
Your brain is going to move forward, but it's going to switch back in part because of all that fluid holding it around. So it adds an extra protective layer. And this is the lateral view the side view of the ventricles.
We've got lateral ventricles with third ventricle. And or fourth ventricle, and then the cerebral aqueduct, which is going to connect down into the spinal cord, and the fluid is going to move in a stereotypical pattern.
Remember, the ventricles are aligned with those epidermal cells have cilia. The cilia is a, and we're gonna move the fluid through our ventricles.
So if we follow that path,
we start with the coronoid PLEXes,
making the number one and that CSM is going to flow through our vegetables into the sub or acclimate space in between that layer.
And some of it is going to enter the central canal of our spinal cord and go down.
The rest of it will flow through the space and then be absorbed via the dural venous sinuses into the via villa of that arachnoid layer.
So little protrusions into the where we can absorb some CSF, and it will go back into circulation into the rest of the body. But the rest of continue to be.
The brain and CSF, the other thing to know about CSF is it will go down your spinal cord.
And so,
if you've ever heard of someone having to get spinal tap before or a lumbar puncture lumbar being a lumbar region and spine,
that's generally where they'll stick a needle in between the vertebrae and they'll remove some of that cerebral spinal fluid.
And so some reasons why they do that one is maybe they want to test and see what is in the cerebral spinal fluid again. They want to see what maybe what's circulating around in our central nervous system.
They might have to do a lumbar puncture or a spinal tap to get some of that fluid. They also might do it to relieve pressure. So this fluid is circulating around the brain.
But if the brain starts to swell all of that fluid has nowhere to go. Right into that might create an increase in intercranial pressure or brain pressure. And so what they can do is they can drain some of that fluid out from the spinal cord.
And that will relieve some of the pressure on the brain.
Okay, so the blood brain barrier, we talked about this before, but the blood brain barrier is our last protective measure. It is the ultimate gatekeeper.
So, again, this is made from the barrier between our blood vessels and Astro sites in the clear that help form those barrier between our brain and our body.
And again, we have blood vessels, capillary cells in there. They're connected with tight junction. So that means that things are not gonna flow through.
Okay so water glucose and amino acids are the only two usable water soluble substances, the majority of things, things like ions, for example, or large molecules toxins that's going to stay in the capillaries.
And we have special transporters that will instead just bring in what the brain needs to the brain needs glucose. The brain needs amino acids and the brain needs some water and.
The transport of glucose is especially important, because your brain can only use glucose. Whereas other parts of your body can undergo different processes to turn proteins or fat into energy. Rain can't do that.
Your brain only has glucose transporters and so it can only taken straight sugar.
Which is why, if you get hypoglycemic or you have low blood sugar, you're gonna start to feel kinda like headed and Rosie, because your brain isn't getting the glucose that it needs to do its functions. So you feel that way.
She usually just you sheet sneakers bar to eat Snickers bars, or remember that commercial tells you to do. That's valuable things as with all membranes flat fat soluble molecules are gonna easily diffuse in.
And then gasses also don't need a transporter. There isn't gonna go through things like oxygen, carbon dioxide, laughing gas very easy to get into the brain very quick to get into the brain again because of the gas.
And so, if you work, eventually, if you're working in the pharmaceutical industry, and you're interested in designing drugs for the brain, you have to keep in mind that the vast majority of things don't get into the brain.
And so it either needs to be fat soluble, or it needs to be gas, or it needs to be similar enough to an amino acid or glucose that it can be transported in. Because otherwise it's going to stay in the blood. And it's not going to get into the brain.
So this is a huge roadblock in the pharmaceutical industry when we're trying to get drugs that target the central nervous system. Okay. So question, you might see is describe ways you protect our central nervous system.
You talk about things like bones, fluid, blood brain barrier, forming that blood brain barrier. Okay all these, these key ways that we protect our central nervous system.
Are there any questions? So far you can take them in the chat a little water.
Okay, so we're gonna keep moving. We're talking about some diseases. So this is a picture of the Patriots playing some excellent football here.
And I'm trying this is because one of the more common brain dysfunctions,
or that's gotten a lot of media attention or traumatic brain injuries or TBS and again,
all of these issues that arise from from brain disorders are because neurons are.
So the reason we care about brain injury, so much is because the brain cannot repair itself in the same way.
A lot of other organs can and so traumatic brain injury repeated brain injuries can have really long term, lasting, lasting issues.
So we use words, like, concussion, which is going to be a brief loss of consciousness. There are all sorts of concussion protocols and standards to check to see a real concussion to create a concussion.
But generally, it involves a brief loss of consciousness and some confusion, some issues that arise right?
After the event and ten persist, depending on how bad the concussion are or weeks months at a time after a confusion is just a bruise.
So, confusion, when we're talking about brain injuries, a lot of times, it's the force of your brain hitting your skull.
So, if you dive and you hit the ground really hard, or if you're driving and you hit the brakes really hard, your brain is going to keep moving forward even as your skull has stopped. And so your brain will hit your skull.
And if it's bad, it can, cause a confusion or Bruce, and if it's really bad here, you can get a concussion, another term gets thrown around and another symptom of TBI, our intercranial hemorrhage. So this is a brain bleeds.
A bad a brain injuries can cause brain bleeds with a little blood vessel in your brains to leak blood. This is a problem again, because we keep the blood and our brain under very tight wraps. Right? It's in that.
It's sealed away with that blood brain barrier. And the fluid in your brain, it's not blood. It's and so bleeds are bad. Not just because there's what? That blood is pushing away the CSF and it's hard.
It's harder to clean up then in other areas of the body.
So, break leads are more serious in that regard and finally, we'll talk about cerebral edema, which is a swelling of the brain as I said before, brain is in a closed system CSF.
And so if the brain starts to swell, it can create this increase pressure. Because the, the fluid you see that has nowhere to go. So that needs to either be relieved. Usually the spinal tap otherwise known as a lumbar puncture.
We talked a little bit with a about stroke. Strokes are the third leading cause of death in the United States. The other name for stroke is cerebral vascular accident or CBA. So, in the medical field, you'll see strokes abbreviated as CPA.
And some of the main symptoms are paralysis, you can get the, which is half of the body could go and have no no motor function, which is the process. You can't move the half the body and again, it depends on your dominant side.
So you are right handed the left side of your brain is going to control. A lot of the left side will control the motor function on the right side of your body and the right side of your brain will control the motor function on the left side of your body.
So, depending on where the stroke is, that will determine the motor depth that you have, you also have language deficits. Again we call those ages. Those will vary, depending on where it is.
And this is all cost by what we call a transient ischemic attack. So usually, it's a blood clot that travels up into your brain and cuts off the oxygen supply to that region.
And if it's small, the body will just dislodge it itself. And the small strokes are not as big a deal.
If it's bad that can cause a rupture in that area, and it will kill off all of the brain tissue right around. When that happens. If it's really big, it will have a much.
Larger area of damage, so strokes, the severity depends on how bad the blood clot is small as big.
Are you able to get to a hospital in time if you suspect someone is having a stroke get immediate medical attention right away? Because they're drugs that they can be given that will help dislodge that blood clot before burst.
So they need to very quickly be brought to medical attention signs of a stroke, or again can be like, a drooping face on one side.
Usually confusion and then language deficits, slurred speech or nonsensical speech, or some of the major signs that a person having a stroke.
Okay, so we're gonna move in our central nervous system. We're focusing on the break spinal cord. So your spinal cord is the information highway of your body what connects your peripheral nervous system to your brain? It's about seventeen inches long.
It runs from your skull. It doesn't go all the way down. It stops in around L one L two and your lumbar region. It is also surrounded by a layer of or three layers of energies and coming out of your spine.
You have thirty one pairs of spinal nerves at the very end. The spinal cord becomes a region that stress nerves that we call the region.
This is named because I've never written a horse before people. Tell me, if you ride a horse, the inside of your legs can get sore those muscles inside of your legs. Your muscles especially can become sore.
Well, the very end of your spine, and the cottage point of region is what innervates, or give sensation and motor function to the inner part of your legs.
And so if you get damage to the end of your spine, if you get damaged in the region, you'll go numb and be unable to move the inner part of the.
So, that's where they came up with the name of the horse back riding what becomes sore inner part of the legs.
Okay, so this is a view of the spine you have spinal nerves, and they're named for the spinal region that they come out.
So the ones that are in the cervical region,
by your neck,
cervical spinal nerves in the chest,
or the rasikh nerves,
and then the end with the lumbar nerves,
and the very tail becomes quite a region,
which will shoot off a few sacral spinal nerves the spinal nerves are for the spinal cord is thicker in two regions,
and it's thicker,
because a lot of nerves come out of those two regions.
So it has a cervical enlargement and a lumbar enlargement. Cervical enlargement is because it's going to send up all of the nerves for your arms and the lumbar enlargement sends up all of the nerves for your legs, or the majority of nervous regulates.
And so those regions are bigger and your spinal cord, because it could fit. All of those narratives branching out to those larger areas in your body.
If we look at your spinal cord, we can break it if we do a slice, we look at it and we see that there are two different regions. There is gray matter. It looks gray versus white matter. The white.
We have a dorsal horn and eventual more dorsal being back the tripping front in the dorsal horn. We're gonna have the cell bodies of the entering sensory neurons.
The sensory information is gonna be the dorsal side and the ventral side. It's gonna be the motor and they will send out roots, which are gonna fuse and become spinal.
So in the spinal cord, we separate sensory and motor function. This is why some spinal cord injuries if it's not a full bisecting injury. So, it doesn't completely break the spinal cord.
The patient might have either sensory deficits or motor deficits. So, if they just damage the dorsal part of their spine, then they're gonna just have issues with sensory from that level.
And so they get lumbar damage, for example, in the dorsel part of their spinal cord, then they wouldn't be able to feel their legs. It would still, however be able to move their legs.
And this is really interesting because again that motor parties in the ventral part of the spine, so the sensory that's damage, they can no longer feel their legs with the motors intact. They can still move them and their versus true. So if they damage the ventral part.
It can still feel their legs, but they won't be able to move them. And so with spinal injuries, you need to pay attention to what is damaged or whether both are completely damage.
The game where it looks like, you see the gray matter, and the white matter, the sensory, and the motor neurons are gonna run off and then sometimes they come together. They form that spinal nerve.
So the spinal nerve is gonna have both sensory and motor input, sensory going up the spinal cord motor input, going out from the spinal cord. They'll come together in the spinal nerve, but the branch, when they enter into the spinal cord itself.
So again,
the white matter in the spinal cord is made of those fiber tracks via different columns,
the sensory tract is an Afro track it approaches the spinal cord and brain and the motor track is ether inter exiting.
It's gonna lead from the brain down the spinal cord and this is again what that looks like we're gonna get integration through the thalamus is that relaxation gonna go up to different parts of the cortex and decide what to do and send a response.
So, we can start the sensory receptor. We have an afferent or approaching sensory neuron that's gonna go into the spinal cord.
So, up into the brain, this decision was made movement will come down a front pathway and go out a motor questions to consider in general questions.
So, we're gonna with that we'll talk a little bit about peripheral, nervous system. For this part. We'll talk about the general structure of our peripheral nerves. We'll identify cranial nerves and lesser function. And then we'll talk about our sympathetic and parasympathetic system.
So, what I want you to know here again, can we start talking about the spinal nerves? Is that nerves are bundles of fibers and most of them are mixed. So mixed nerves are all of our spinal nerves.
So,
everything coming out of your spine has sensory fibers and motor sensory coming from the body up to the spinal cord motor fibers,
coming down from the spinal cord where you have some nerves in your body that are also just sensory or just motor that all of your spinal nerves have both,
but some of the other nerves in your body,
we'll just have one or the other.
Okay that is where we're gonna leave it for today.
Any questions people have any questions on what you need to be working on material. We just covered, we finished the central nervous system. We have to start the peripheral nervous system. Okay. I'm gonna stop the recording here.
