Ascending Tracts | Spinothalamic Tract

iein engineers in this video we are going to talk about the anterolateral system or the spinothalamic tract okay so this is gonna be a very very interesting track very in-depth I'm not gonna lie it's gonna we're gonna cover a lot of stuff so once you guys just stay focused with me and hang in there out so it's good let's get started guys so when we talk about this system and again which system when we talking about we're talking about the ante row that's a couple different names okay just so that you guys know we're talking about the anterolateral system another name for it is also referred to as what's called the spinothalamic tract okay and it's actually broken up into two parts and we'll discuss that on the anterior or ventral and the lateral spinothalamic tract well we'll talk about this I promise and we'll get there alright so now first things first before we even start going into the tracks we have to know what is the function of this anterior lateral system what is its function so now what I want to do is let's come over here in the middle and let's write down the basic components this the spinothalamic tract and again you can call the anterolateral system or the spinothalamic tract but you have to understand there's two divisions here of the spinothalamic tract okay there's the ventral or anterior and then there's a lateral spinothalamic tract now earlier studies revealed that these two carried separate types of information and we're going to stick to that but I want you to keep your your minds open because they're finding now more research that these two aren't as clear-cut as we thought they were what do I mean the anterior is believed to only carry sensations with respect to crude touch or very very light touch in other words you can't discriminate this type of touch okay and another type of sensation called pressure but specifically more around long like the superficial pressure okay that's what they believed was a responsibility of the anterior spinal thalmic tract or another word is ventral spinothalamic tract okay the lateral it is believed to carry specifically pain and temperature sensations okay and there's two different types of pain there's fast or pinprick pain and then there's slow pain and we'll talk about that and then there's tempers temperature sensations right so the extreme temps cold or hot and we'll talk about that again but I want you to keep your minds open they're finding that this isn't always the case they're finding that some of these sensations are kind of mixed and intertwined so that they actually that's why they treat it as the entire anterolateral system because the entire anterolateral system carries crew touch pressure pain and temperature but just for the sake of simplicity I will we're going to keep it separate in this situation okay it's very simplicity sake okay so we know that the spinothalamic tract has anterior and lateral we know the anterior carries crew touch and pressure laterals pain and temperature now the next thing that we have to discuss is how do we cuz this is going to be the main focus here's the pain and temperature pathway how do we stimulate this pathway what is the way that we can stimulate this pathway so the next thing you need to know is in order for us to be able to sense pain or sense extreme temperatures we have to have some type of receptor to pick up that stimulus so now we have to have some type of receptor okay now what kind of receptor is this that actually picks up pain and temperature you know there's different types of receptors there's noise acceptors there's Meccano receptors there's thermo receptors there's so many different types inteiro receptors this type of receptor that we're going to discuss here is going to be of what's called the noise acceptors okay noise acceptors these are basically going to be the ones that are picking up tissue damage or extreme temperatures okay so these noise acceptors are picking up two different types of stimuli right what is that it's going to be picking up tissue damage maybe this tissue damage is because of chemical burns or because of some type of mechanical situation like you freaking slam your finger and the pliers or something like that or it can respond to extreme temperatures okay you're outside you know with no gloves on throwing around snowballs or you stick your hand and you know really hot water whatever it's it's responding to those types of situations so we know the receptors that are responding to it we know what they're responding to it but we have to dive in a little bit more into that we have to understand how does tissue damage how does extreme temperatures activate these noise acceptors okay so now we have to understand that there's three different ways that we can stimulate these noise acceptors but before we do that we have to have two different types okay so here this blue one this is going to be one that we're going to refer to as a delta okay these are a delta fibers a delta fibers are specifically for what's called fast pain or pinprick pain okay so like I take a needle and I stab your hand right I just stab the epidermis these guys right there are located within the epidermis they're found in many different places epidermis dermis you can find them even in your cornea you can find these suckers everywhere alright so now these a delta fibers are going to respond to that pinprick pain well what types of things really stimulate these guys let me tell you there's only two main things that stimulate these guys one is temperature and the other one is thermal sensations so let's say that I want to stimulate this guy and if I want to stimulate him I need to activate him by mechanical stimuli in other words take that example I smashed my finger with pliers on accident all right so there's mechanical stimuli because this one mainly responds to that another one is really cold temperatures okay so really really cold temperatures the way these things work is let's pretend for a second I kind of zoom in on this receptor here let's say I zoom in this receptor right here here's the receptor here's like the bulb of it right you have different types of little channels on this receptor let's pretend I put a channel right here here's a channel and here's another Channel let's say I smash my finger right once I smash my finger there's certain types of channels that are mechanically activated that they can deform them alright so let's say that you give you smash your finger with the pliers that mechanically changes the shape of this protein if it mechanically changes the shape of this protein what can enter in maybe sodium ion scanner area if sodium ions enter and what is it going to do to this guy it's gonna stimulate him and send these action potentials down this actual peripheral process or this a delta fiber what about temperature how does that do it you know there's different types of channels here that are very sensitive to cold temperatures or even hot temperatures you know there's different types of thermal receptors here you know they're under a category like TRP V receptors or transient cation receptors channels and their permeability changes due to the fluctuations in temperature so there's extreme cold temperature it might change the permeability of this channel and then guess what maybe some sodium lines start flowing in alright because of the extreme cold and what does it do cause the cell to become more positive and triggers action potential so that's really cool so now we know that a delta fibers or fast pain are activated by cold temperature and mechanical stimuli we have another one because if we have these a delta we're gonna have another one called C fibers okay and this is our slow pain this is for the slow pain now how would you describe the slow pain it's more of your burning pain the aching pain the dull pain and you're not able to localize this pain as well as you could and prick pain or fast pain so what can stimulate these guys so pretty much similar to whatever the a delta is so for example let's say that there's actually going to be really hot temperatures so we're taking the opposite here so hot temperatures alright if there's hot temperatures that could stimulate the C fibers or mechanical stimuli again mechanical stimuli this also can cause the activation of these receptors these noises scepters but there's one more this one's a little bit more prominent and that's chemical factors the chemical stimuli so whenever there's tissue damage you know how they've found that out there let's say that I slap my hand right I slap my hand there's gonna be a little bit of tissue damage there that tissue damage is gonna cause a lot of inflammatory chemicals to be released they found that because if you go and you take a sample of that to find a lot of different chemicals what are some of those chemicals for example well some of them the most important one one of the big ones is protons so you're gonna have a lot of protons in this area protons are basically coming from the metabolic acids which are inside of your cells what else you know 97% of our cells are rich in potassium so potassium is also going to be released out in that area what else another chemical called bratty Kynan this is another one what else histamines histamines are also another important one and these guys are going to be released and they're going to stimulate this actual pain fibers these C fibers the slow pain fibers so if you have to remember remember the chemical factors see chemical are pretty much the entire stimulation for the C fibers they do respond to some mechanical and hot temperature but their main stimulation is through chemical factors a delta respond to cold temple stimuli not very much of it responds to chemical all right now since we're kind of grouping this together we also have other types of receptors which are going to be picking up crude touch and pressure what are those you know you have different types of receptors over here which are called you have what's called murk anyhow it was called Merkel's disks Merkel's disks these are for kind of your superficial pressure and your fine touch and then there's another one which is your peri tracheal nerve endings these are basically surrounding hair follicles and then another one which are pretty much the most important ones is your free nerve endings okay your free nerve endings can also respond to touch and pressure so you have free nerve endings which is the big ones the peri tracheal nerve endings which are around your hair follicles they respond to bending of the hair and then Merkel's disk which kind of responds to more of the superficial pressure and some of the touch so now that these fibers they can also pick up that crew touch so what can they respond to they can respond to crude touch and they can respond to pressure these can be stimulatory factors for these guys so now we know what is actually going to be picking up we know how we're actually picking up this tissue damage or these extreme temperatures and then for the last situation we know how we're picking up crude touch and some superficial pressure we know these big points here the C fibers the a delta fibers very very quickly why do they call them a delta why do they call them C and if you really want to know because I know you guys are always interested in learning more these are generally again they can be a delta and c fibers also you can have a mixture of these but now why do they really quickly why they call an a delta and C it's dependent upon the myelination so you know when you talk about myelination let me get this out of the way here guys so myelination axons can be myelinated to varying degrees so when we talk about nerve fibers there is of three types we're mainly only going to focus on a and C but there's a B and C we're mainly gonna be focusing on a a is highly myelinated B is moderately myelinated this is more for the sympathetic motor neurons here and parasympathetic C are going to be not myelinated so myelination determines the speed of the actual action potential so a would be the fastest B would be next and C would be the slowest thus the fact of slow pain they're not very heavily myelinated so they don't move very fast for the action potentials hey there's a many different types we'll talk about this more in the dorsal column but there's a alpha a beta and a Delta a delta is the one that's picking up the actual fast pain or the cold temperatures C is the one that's actually going to be the slow pain so that's why I just wanted to mention that really quickly where this a delta and where this C is coming from cuz I don't want just throw that out there and just accept that you guys know it all right so again a heavily myelinated C lightly mounted it's really really important because it determines the speed of the action potential okay cool so now we know what this tract is responding to we know the receptors that are picking it up now we have to talk about how is it going into the spinal cord so I wanted to before because it's gonna get kind of messy so I want to blow up a big cross section of the spinal cord so we can see how these fibers are coming in and so it's not too messy so if you look at the cross section on the spinal cord here we're not going to talk about it in great detail but there's they kind of section it out into different like what's called lamina they call them rex lamina if you really want to know it's called rex lamina we're not going to talk about that in great detail we're gonna talk about a couple of them that are really important but if it goes like this you have rex lamina 1 2 3 4 and it just keeps going what's important here is mainly actually let me put one more here five the only really thing that's important about this is kind of remembering where these actual fiber synapse in this point for the pain pathway okay so let's say we take for example the c fibers and let me get this out of the way here okay let me get that there so now let's say here we had the c fibers right and the c fibers here was the endings right that was the one that was responding to the chemical stimuli or the hot temperatures or the mechanical stimuli and what happens is this is the peripheral process this part here pick the stimulus this is the pseudo unipolar neuron right the cell body there and then it has the central process which is going into the central nervous system what happens is it goes in alright and we're going to talk about this in a second and it actually ascends and descends we'll talk about that in a second it's called the tract of Lister onlus our sorry so attractive less our but when it does when it ascends or descends it synapse is on specific points for the C fibers it mainly sign APS's in Rex lamina too and in Rex lamina 3 and then from there it goes through kind of a cascade of different types of neurons here throughout this entire process it kind of goes through a cascade of multiple different sign apses and then eventually what happens is these fibers cross they go to the contralateral side and when they do that they go through what's called the anterior commissure and then go up so right here where these fibers cross over it's called the anterior commissure so that's for the C fiber so if you really had to remember the important ones remember - for the C fibers and then remember three for the C fibers okay if you really want to know they call - they call it the substantiality Nosa of rolando and they call three they call it a part of the nucleus Pro Prius all right so that's for the C fibers now the next one is the a Delta where is a delta going in a delta is actually going to be here's again receptor part picking up the stimulus peripheral process pseudo unipolar neuron central process and again trakula sir let's our sorry and then that can go into specific parts here mainly one Rex lamina one and Rex lamina five and then from here these guys again they crossover through the anterior white commissure come over here into the anterior lateral system and move upwards and that's what we're going to talk about but I want you guys to get an idea of where these things are moving what parts they're going into so now remember for this one for the fast pain it's one in five okay one if you really want to know is the marginal nucleus and five is referred to as the reticular nucleus okay or that that lamina area okay so now we know that the last one here and this is again this blue one here let me mark this down this is for a delta the last one here that I want to finish off with is for these actual crew touch again it's not not a super big one here but again same concept here peripheral process pseudo unipolar neuron central process comes in here they not it's not specifically that important where they go in here they believe it could go two three four maybe five but just know that it comes in here and again it could go two three four five and then what happens is it crosses over now it does cross goes to the contralateral side of the spinal cord and it goes through the anterior white commissure but it comes a little bit more anterior so you know over here we have the lateral white column and then over here we have the ventral or the anterior white column this one mainly kind of goes situated within the ventral or the anterior white column and then goes up okay so just remember that so now this is for this pathway is for the crude touch and pressure sweet deal so now we know the pathway we know what it's carrying we know the receptors we know how it's entering into the spinal cord but we have to do one more little touch really really important point super important point is that ascending and descending system I was telling you about and the only reason it's super super important is because of its relationship with like certain types of lesions let's use this marker here so let's pretend I take that pain fiber right there okay here was its peripheral process which is picking up the stimulus when it does that it goes in to the post the post our great horn or right when it goes into the post check right horn it gives off ascending branches and it gives off descending branches and what these do is they can go down they can actually go down maybe one two tops three spinal cord segments or they can go up one two tops three spinal cord segments and they can sign apps on the nuclei in this area that crossover and go up again let's pretend that this one's coming over here this one can come up this one comes over here goes up goes down stimulates here crosses over moves up so it develops this tract if you get an idea of this if I were to draw it at every single section it starts making this tract that's kind of going up and down you see that that tract right there is called the tract of the sour okay it's called the tractor let's our why is this important it really briefly let's pretend that you have a lesion in the spinal cord around t6 t6 the area that's actually going to be affected is maybe two or three spinal cord segments below that on the contralateral side that's why this is important it's important for clinical aspects because of its ascending and descending fibers if there's a lesion at t6 the actual if there's a lesion at t6 right the problem is gonna be two segments maybe three down and on the contralateral side because of this tract okay I think we got it down for this part so now let's come over here and see how this ascending pathway moves up and the different nuclei that it's I naps is on right so let's start here first with that eventual let's do the crude touch let's get that one out of the way so here let's put crude touch right here here's that pseudo unipolar neuron it's responding to what type of stimulus here crude touch which can be coming from the Merkel's disk tu'pari tricky owner of endings the free nerve endings and it's also responding to a little bit of pressure and again what happens here comes in and it goes to this actual cell body this is your first order neuron the first point goes into the dorsal gray Horn sign apps is on the cell bodies of a nucleus somewhere that within the dorsal horn and then does what crosses over through the anterior commissure and goes up alright and this right here they refer to this as the I'm gonna abbreviate it the ventral spinothalamic tract okay we're gonna bring it as the ventral spinothalamic tract and just remember this thing right here this pseudo unipolar neuron it's actually located within the dorsal root ganglion which is kind of located outside of the spinal cord okay so we have the first order neuron which is this pseudo unipolar neuron which is located within the dorsal root ganglion we have the second order neuron which is located within the dorsal gray horn and then the axons crossover anti-white commissure ventral white matter here and then goes up and then a sins okay now let's do the next one let's do this one let's doing that baby blue okay and we're gonna keep this pretty much the same here let's say here we have the pain pathway here right let's say this is our a delta okay our a delta does what picks up pain in cold temperatures so we'll put cold temp okay and that pain could be through cold temperatures mechanical stimuli right sends the information inwards and again it can have that tracklist or where I can go down or it can ascend so I can ascend and descend one to two to three segments synapse is here on the cell bodies right of the dorsal gray horn then from here it crosses over through the anterior white commissure and then goes upwards and specifically where is it going it's going into the lateral white column so this is going to be a component of what's called the lateral spinothalamic tract so you have the ventral spinothalamic tract the lateral spinothalamic tract alright one more thing though we need to read my red marker okay this last one here is the C fibers and the C fibers these are the ones remember they're responding to slow pain that dull pain achy pain they're going to be coming in synaptic on cell bodies in the dorsal root ganglion I'm sorry dorsal gray horn and then doing one crossing over via the anterior white commissure and then moving upwards now the lateral spinothalamic tract let me actually do this is actually both of these things right so the lateral spinothalamic tract is really both of these things but I got to give us one more thing because the a the a Delta right this pinprick pain it's more of a newer kind of more modern concept so because of that they believe that this a delta is a part of they believe it's more specifically what's called the Neo spine o thalmic Hathway that's specifically for the a delta and they refer to the c fibers because they're more of a primitive kind of concept here they're called the paleo spine o salivic pathway if you don't really want to remember that that's fine it's just giving you an idea of the origins the concepts of this okay so see is mainly carrying fibers into the anterior lateral system specifically lateral spinothalamic tract at lateral white column and if it's see it's more of the older concept the older aspect of they believe it the Paleo spinothalamic pathway whereas the a Delta it's more of a newer concept of pain right that's the Neo spinal down the pathway now what happens is is all of these guys come together they all come as one big system that's why we call it the anterolateral system so now let's bring this guy together like this for the crew touch and the pressure will bring this red guy right here and we'll bring the blue one right there smack-dab in the middle okay so now we have this whole thing here this whole antara lateral system some books they even refer to this group of structure here as what's called the spinal lemon niska's okay there's other fibers that are moving up in this and we'll talk about those like spinal tech tools by enemies in cephalic spinal hypothalamic spinal reticular there's so many of these darn things but for right now let's keep it with just this part the ventral spinothalamic tract and the lateral spinothalamic tract which is broken up into two different types of pathways paleo spinothalamic which is the C neo spinothalamic which is the a delta as they come up words they're going to give off certain types of structures so this ventral spinothalamic tract it's mainly going to go up to a specific nucleus within the thalamus and that is called the ventral posterior lateral nucleus and there's another one called the ventral posterior inferior nucleus but these these crew touch and temperature sensations these are mainly going to be going to a structure a lot of them are going to be going to a structure and the thalamus which is called the ventral posterior lateral and there's another one called the ventral posterior inferior nucleus okay you'll see as we talked that there's gonna be a lot of collaterals okay now the C fibers here's the important thing the see fibers are really interesting as they're moving upwards some of them make it up to the thalamus but about 85% of them terminate in this big blue I'm sorry this big orange structure here what is this big orange structure here call this big orange structure right here is called the reticular formation so this big red straw orange structure here is called the reticular formation and it's a piece of gray matter that extends throughout all parts of the brainstem midbrain pons and medulla so a good portion how much of it again about 85% of the fibers terminating the reticular formation only about 15% of these fibers go up to the thalamus here's the thing though these fibers here these red fibers which are coming from the C fibers right the slow pain they go to specific nuclei nonspecific nuclei in the thalamus the thalamus just a brief thing here say I draw a little alamos here there's different parts of the thalamus all right so you have different parts but this structure right here this Y shaped structure it's called the inter medullary sound instrument intermediary lamina right and there's a whole bunch of nuclei that are located within this lamina okay they're called intra laminar nuclei and I have that pink representing that so you're gonna have some nuclei which are lodged in this lamina and these nuclei here are called your intra laminar nuclei and these are really important there's a bunch of them but the main ones that we're gonna be focusing on here if you really like to know that is the Centro median nucleus and another one called the para fasciculus okay so these are the two big ones that are actually a part of the interlaminar nuclei is the central media nucleus and the pair of vesicular a pair fasciculus nucleus and again they're nonspecific what does that mean from here they do a lot of different things they go to different parts from this structure here so from the inter lamina nuclei they can actually kind of go out and supply different areas they can supply the the cortex like the primary somatosensory cortex but they go to two really important structures one of them I'm going to do it like this to represent its significance is it can go to a part of the actual cortex which is associated with the emotional aspect of pain okay this right here let's say that this structure here is called the cingulate gyrus there's another one that I could go to there's another part here which is kind of tucked deep within the temporal lobe and that one is called the anterior this one is called the anterior insular cortex okay so some of these fibers can go out to different parts like the press so Madison sorry cortex the primary and the secondary Association of this secondary so Association cortex but two big ones is it goes to the cingulate gyrus and it goes to the anterior insular cortex and the reason why this is important is because they play a role within the emotional aspects of pain holy crap okay well we're gonna come back to the C fibers because there's a lot more that we got to talk about yet but let's go to this a delta so he's a delta fibers they're also coming up right some of them very little of them give off some collaterals to the reticular formation most of them ascend upwards and go to this nucleus here within the thalamus and again what is that nucleus they're called it's called the ventral posterior lateral this is the main one and some of them can go to the ventral posterior inferior nucleus from there what happens these fibers can radiate so we're taking with us fast pain and we're taking crew touch and pressure to this ventral posterior inferior and ventral posterior lateral from here they're gonna radiate they're gonna go you know you hear you have the internal capsule and you have the anterior limb in the posterior limb there's a part here the posterior limb which is the posterior one-third of the internal capsule it can actually hop on that and then go to the corona radiata and supply large parts of the cortex what is that part of the cortex that is supply I'm going to breve es1 and it goes to what's called s2 okay and these areas of the cerebral cortex they're actually located on specific port part of the brain anyhow what's called the central sulcus so let's imagine here I draw a small little diagram here's the central sulcus here I'm going to draw like this here's your central sulcus behind the central sulcus you're gonna have this gyrus here which is called the post central gyrus the post central gyrus there's another area just a little bit behind it which is called the secondary you know a secondary Association cortex right the secondary somatosensory cortex so this right here is s2 this right here is s1 what I'm doing is is we're taking a slice we're taking a coronal section here and if I take a coronal section right here we're gonna see that we're focusing on all this part right here this is all parietal lobe okay so it's going to be supplying a large part of the parietal lobe and taking this actual information these sensations to different parts of the cortex s1 and s2 mainly to help us to become consciously aware and to understand the concept of that pain all right okay so we got the information going to the cerebral cortex primary somatosensory cortex secondary somatosensory cortex we got branches off to the cingulate gyrus and the anterior insular cortex sweet stinking deal now we have to come back to this over here the C fibers along the way there's other components right well we're good with the C virus we have to talk about one more thing along the way there's other fibers that are associated with this entire anterolateral system so if we talk about that let me add these ones in so in the anterolateral system so again we are going to go ALS okay this is not a myopic ladder score so we're talking about the anterolateral system there's different fibers right we're going to be carrying with us the lateral spinothalamic tract the anterior spinal thalmic tract and there's some other ones right another one is we're carrying with us what's called the spine Oh tactile tract we're also carrying with this anti ladder system the spine Oh knees and cephalic which is really important tract and these are just fibers that are part of this whole system here and there's another one and this one is actually gonna be called the spinal hypothalamic tract and there's actually one more here and this one is actually going to be called the spine Oh reticular tract we've already kind of covered that though these little branches these collaterals that are coming off from the anterior lateral system but now we have to cover the spinal tectal and the spinal meas and cephalic really quickly so coming up through this you have let's do the spinal tectile first so where is the tectum you know if you look here you take like a different type of section here of the brain we take like a sagittal section we can look at the central nervous system like this and on the back of the midbrain you know these two little swellings okay they call it the Kapur quadrigemina which is made up of the superior colliculus and the infant colliculus we're gonna take information to the superior colliculus specifically so it can help to move our eyes or head to wherever or this actual stimulus is maybe I stepped on a Lego or something like that I move my head my eyes towards that area so now coming up through here here's the midbrain we have to give off collaterals in these collaterals that we're going to give off is gonna go to this structure right here look at this structure right here this structure right there we're gonna call this right here the superior colliculus but it's a part of it's a part of the tectum but we're gonna put the superior colliculus so this tract right there these fibers that are giving off these little collaterals that are going to the superior colliculus or the tectum is called the spinal tactile fibers then we have some other ones we have the spinal Me's and cephalic so you see these nuclei right here there are the pons this is called the para brachial nucleus of the pons right so the pair break heel nucleus this is gonna give off some little collaterals right so we're gonna give off these fibers these collaterals are gonna come off to the para brachial nucleus why is this important remember I told you peih-gee's is emotional sometimes it's it's really sad you know so what happens with these guys these pair brachial fibers they can send axons upwards let's use this one for example since we're it's kind of crowded over here these guys can send axons upwards and they can go to a special structure located within the actual cerebral cortex I'm sorry within the cerebrum deep within this treatment so deep it's a piece of gray matter deep within the cerebrum there's a special structure up here let's do this one in this green right here there's a special structure right here that's associated with the fear and the emotional aspects of pain right and this is called the amygdala okay this is called the amygdala so we have a connection between the pair brachial nucleus and the pons and the amygdala and what is this little track that's coming off here these fibers that are coming off to supply the pair of brachial nucleus and another structure that's gonna be called the spinal mise encephalic tract so two structures the spinal reasons value is going to supply what is the parent brachial nucleus and the pons which will go up to the amygdala which is controlling the fear and the anger and the painful aspects with within right the other one we said is the superior colliculus is giving all fibers to that which is called the spinal tectal now the parrot there's another structure here that this actual anterior lateral system is going to give - it's right here you see this right here in the midbrain you have what's called the cerebral aqueduct and there's a piece of gray matter that wraps around it that piece of green matter that's wrapping around the cerebral aqueduct is called the peri a quid ductile it's actually a do it like this peri it was 2p AG periaqueductal gray matter let's do that peri Eiko ductile grey matter it's a piece of grey matter surrounding cerebral adduct what happens is some of these fibers via fibers from the spinal meas in cephalic right spinal me since of phallic fibers can give off collaterals to the periaqueductal gray matter why is this important we'll talk about this in another video but the periaqueductal gray matter controls your descending pain modulation pathways they can control the pain it has different descending fibers that can go down and release norepinephrine and serotonin that can help to modulate the pain by releasing different types of in Kathleen's and orphans and dine orphans we'll talk about that after okay so we've covered that now one more you know right up here you're gonna have another structure and that structure is called the hypothalamus let's just say that as we're going up here as we're going up we give off some collaterals here from this anterior lateral system to another structure right here and let's say that this structure here we're talking about is the hypothalamus so this right here is called the hypothalamus so that's called the hypothalamus so let's say that you get kicked in the nads right what happens it can cause you to maybe become nauseous it can cause you to increase your heart rate maybe in change your respiratory rate and depth why because these collaterals that are coming off and going to the hypothalamus the spinal hypothalamic fibers the hypothalamus controls our autonomic nervous system so these spinal hypothalamic fibers that are coming here and supplying the hypothalamus controls our autonomic responses to pain changes in our blood pressure changes in our heart rate changes in our respiration right so different things like that or think about a woman giving birth it's gonna do what it could actually trigger oxytocin release and he controls our hormones right or even the suckling reflex so the hypothalamus controls a lot of the aspects the autonomic effects of pain okay one last thing guys and we are done is this last part here we didn't finish up on this we've said that 85% of the fibers from the 85% of these C fibers go to where the reticular formation the reticular formation is so so so important what is the function of your reticular formation it controls the alerting the arousal the wakefulness of the entire central nervous system so when every year awake or if someone screams right our reticular formation can sift through all the nonspecific not really important information and help us to become aware of the most important the most recognized situation or whatever sensation it might be whenever you go to sleep though what happens to your reticular formation it shuts off and think about this let's think about me saying something out loud and the impulses gets to travel down the vestibular cochlear nerve right you don't hear that sound when you're in deep deep sleep why because your reticular formation is not alerting your central nervous system of that or if you touch somebody and they're really really deep sleep and they don't wake up does that mean that they're not able to pick up those touch sensations and send it up to the central nervous system no it just means that their reticular formation is not going to be alerting the cerebral cortex of that touch that's the beauty of the reticular formation so in certain types of pain like think about this it's really simplistic if you think about it and you have arthritis or you have a lot of achy pain right that dull or burning pain what's it doing to your reticular formation activating it a lot of them 85% of fibers well what does the reticular formation what did we just say it does it pretty much sends these fibers upwards okay and these fibers go to these interlaminar nuclei the inter laminar nuclei what do they do they supply the primary somatosensory cortex the secondary somatosensory cortex and it's gonna go to main areas which is the anterior insular cortex and the cingulate gyrus but the big thing with this is is the reticular formation is alerting almost your entire cerebral cortex why is that important think about it when you're trying to sleep but you're in pain because of arthritis or achy or dull pain why is that it's because it's alerting your reticular formation your reticular formation is telling your entire cerebral cortex hey I'm in pain so that's one of the crazy things about this okay one last thing I want to talk about guys so remember how we said that with these C fibers right they come over to the dorsal root ganglia they cross over to the contralateral side and then ascend right as this lateral spinothalamic tract but particularly the Paleo spinothalamic pathway of it we'll just remember that it's not always contralateral some of the fibers some of them not all of them but some of them can also stay oopsey lateral it can stay tipsy lateral and then give off collaterals to the reticular formation right and some of them can actually reach the intra laminar nuclei and then go to different parts of the actual cortex so it's really important to remember that these C fibers cannot only go contralateral but they can also go hip C lateral via this is called the spinal reticular fibers right it's the ones that are going to the particular formation 85% very little maybe 15% of them goes up to the inter laminar nuclei an engineer's we covered so much information if you guys stuck in throughout the whole video I can't say thank you enough I hope you guys really enjoyed I hope you learned something if you did please hit that like button comment down the comments section please 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Channel: Ninja Nerd

Views: 470,411

Rating: 4.9684205 out of 5

Keywords: ascending tracts, spinothalamic tract

Id: Xy2J_zzRjDI

Length: 45min 36sec (2736 seconds)

Published: Mon Jan 08 2018