hi ninja NES in this video we're going to talk about the structure of the eyeball all right so let's go ahead and get started with this because it's important before we start going into all the photo transduction and going into the retina and looking at all the cells layers of the retina and how these optic pathways are even occurring going to the central nervous system we really need to just get a good idea about the anatomy of the eye right so if you guys have watched some of our Anatomy videos we have a model that we actually go through the eye but this is just going to go to a little bit more detail and apply some physiology to it okay so let's go and get started so the what are we going to try to cover in this video let's come over here and let's get our little outline set up first thing we're going to talk about is the tunics of the eye okay then I want to talk about these things called segments like anterior segments and posterior segments and what separates them and what's in them then after that we're going to talk talk about the flow of this substance called aquous humor and you know we might even throw in another thing called the lacrimal flow okay we might even talk about the lacrimal flow and then we'll throw in a tiny little tidbit in there about clinical correlations nothing really insane all right so let's go ahead and start about tunics so there's actually going to be three main tunics of the eye three main tunics what are those three main tunics okay one tunic that we're going to talk about is actually called the fibrous tunic that's the first one we'll start with the fibrous tunic and this this is made up of two things okay so the fiberous tunic is made up of two things one of them is going to be the Scara and we'll talk about the Scara and the other big component is actually going to be the cornea okay the other one's going to be the cornea so the fibrous tunic we're going to talk about is actually going to be made up of two things one is the Scara and the other one is the cornea then after that we'll talk about what's called the vascular tunic or the uvia okay the vascular tunic sometimes they even call it the uvia uvia all right we'll talk about that and this is made up of three different components right so this is made up of What's called the choroid which is a nice dark pigmented membrane that is important for basically preventing the scattering and of Light by absorbing that because it contains a lot of melanin in that area also has a lot of blood vessels so it gives a nice good vascular Supply to some of the layers of the retina okay then there's going to be What's called the iris and the iris is important for being being a to control specifically the pupil hole size all right and what's called the ciliary body which is made up of two things the ciliary body if you guys know is made up of two components one of the components is called the ciliary muscles so we're just going to call it the ciliaris right and the other one is called the ciliary processes which are the structures that actually make the aqueous humor and then we'll talk about one more tunic and we're actually going to have another video specifically digging into that into more detail but then the last one we're going to talk about is actually going to be the sensory tunic the sensory tunic and this is basically the retina okay so we'll talk about that one and they even include into the sensory tunic we actually throw into this not only the retina we also throw into this a little bit of the vitous humor because it's it's kind of in that area but it's more of what's called in a segment but we're going to kind of throw it in there a little bit with the sensory tunic okay all right so what do we have here we have the fibbr tunic which is made up of the Scara and the Cornet let's start with that first where would you find the Scara in here and what is the Scara made of all right so if you look here we're going to have this outer part of the eye and the outer part of the eye is actually made up of this nice you know there's actually three layers of this Clara so if we actually kind of I'm not going to go through every single uh component of each one but I'm going to say that they're is three layers to the Scara so if we actually have the Scara here there's actually three layers of the Scara one is called the episclera so that's the outermost part of the scar and it's made up of a really nice dense uh fibrous connective tissue right very uh rich and dense fibrous irregular connective tissue then underneath that you're actually going to have another one it's called the Scara proper and the Scara proper is also important because the Scara proper is actually going to be made of a lot of collagen so a lot of collagen fiber so it makes it very tough right very very um resilient and the last one is actually going to be What's called the lamina fusa and this is basically very pigmented so it's pigmented so it actually is going to have a nice color to it okay so we have the lamin fusa and then you're going to have the episclera the Scaro proper and the lusco right so there's three layers Ty Scar and it's a really really important layer and again it's made of like an opaque connective tissue there is clinical correlation to this because sometimes in certain situations like jaundice certain Billy ribon types of molecules can accumulate within the Scara and it can actually cause off like a nice little jaundice like color they say right so you can actually see that in Scara uh and also very very prevalent in people who have what's called Gilbert's Disease which is basically they produce too much Billy ruin and accumulates there all right anyway that's the scare then what's the other part we said it was the cornea this big old orange sucker here right so the cornea is also important so let's write over here the cornea so the other super super important component here is going to be the cornea now the cornea is important because it's actually made up of you never you never believe it uh it's actually made up of five layers it's five layers uh just to make it really simple there's one 2 3 4 five there's an epithelial layer and this is actually probably of the most important one so it's a very very thin epithelial layer okay so there's an epithelial layer and this is the outermost so we're actually going from the outer all the way to the inner layer okay so this is going from Outer to the inner part of the cornea this is the epithelial layer the epithelial is actually rich in a lot of what's called No acceptors or pain receptors okay so it's also rich in a lot of what's called No acceptors or pain receptors why is this important because you know whenever you have something irritating the cornea what are you going to want to do there's irritation of the coret that's going to be sending signals to cause you to want to Blink right so we have pain receptors there to help us to let us know if there's any type of irritation to the cornea also you're going to have other layers underneath you know not super super simp U important but there's What's called the Bowman's membrane there's three layers of connective tissue the Bowman's membrane then after that there's actually What's called the stromal layer this is a very thick layer this is made up with some connective tissue here and there's also going to be another one called the Desmond's membrane and this is another connective tissue layer here so you have What's called the epithelial layer the Bowman's membrane the stromal layer the Desmond's membrane and there's also one more layer called the endothelial layer okay all righty now what's interesting about the coin is that it doesn't really have a lot of blood supply okay it doesn't really have a lot of blood supply specifically the epithelial layer too so because of that that's kind of interesting that's why you whenever you can do cornal transplants you can actually do a Coral transplant from one person to another without having any type of rejection because there is no immune um molecules in that vicinity really okay so again the corny is made up of five layers epithelial layer Bowman's membrane stromal layer Desmond's membrane and the endothelial layer and this is where a lot of the blood flow is actually coming in through to give Supply to some of the other structures okay so I did a little bit of blood supply coming here near the endothelial lay okay to give a little bit of nutrition to the actual layers around this area okay all right that's the cornea what is important about the cornea you know the cornea is important for doing what's called it's helping to actually allow for the light to pass through here so it allows for the movement of light so let's say here is actually going to be light it allows for light to pass through the cornea so it's very very good at allowing for light rats to pass through okay so that's one function of the cornea it allows for light rays to pass through all right sweet so we've gotten a a part of the Fibber tunic which is made up of the Scara and the cornea let's move on to the next part the next part we said is the vascular tunic and the vascular tunic is made up of what three components the choid the iris and the ciliary body which is made up of the ciliaris and the ciliary process let's talk about that okay so let's start here first with this big old maroon uh structure right there okay what is that big old maroon structure right here called this one coming down this way this one coming down this way that's called the iris okay so it's called the iris so if you guys have seen it like looking at from an anterior view you can kind of imagine it like this let's say here's the pupil which is the hole between Iris like this right here this is actually the pupil right here it's a little hole between the iris right around it you're going to have all of these actual muscles so this right here that I'm drawing with these lines is supposed to represent the iris and that's made up of a lot of muscles you know there's two muscles that make up this right here so again what is this structure here called this structure here is called the iris and the iris is actually made up of two different muscles okay so one of the muscles is actually going to be What's called the dilator pupila okay so one of them is called I think that's actually I put the P let's put the pupila so the dilator pupila another one is going to be it's called the sphincter pupila the reason why I'm mentioning this is because the dilator pupila is underneath what's called sympathetic nervous system innervation whereas the sphincter pupula is underneath parasympathetic nervous system innervation so what do I mean here if the dilator pupila is activated it'll cause the actual Iris muscle to relax which will cause what what will it do to the pupil hole so if you imagine here let's say that I have the pupil here is expanding okay it's getting bigger if it's expanding that means that it's dilating the muscles are going to be be causing that dilation of the pupil that's the the job of the dilator pupila okay but let's say for whatever reason the parasympathetic nervous system fibers are innervating the sphincter pupila and it's causing the actual Iris to contract and constrict that pupil hole and it's acting like ainter that's called the Shiner pupila okay so again dilator pupila dilates the pupil sphin your pupila constricts the pupil simple as that and again it's made up of a nice muscular layer so it's made up of muscle there right the dilator and the kinter but you know what else is important it's also pigmented so it's also having some pigmentation to it so it also has pigmentation it's what basically determines the color of a person's eye so for example you might have brown eyes you might have some hazel eyes you might have green eyes or you might have blue right and all that's detered in these darker colors are just the accumulation of more of this actual pigments you know when actually we were born most of us almost all of us are born with like kind of like a slate gray or bluish pigment right and then over time the actual real pigment of our actual Iris comes out okay all right sweet so we got the iris then we're going to go into the next one this big big structure right here you see all this part right here this whole thing right here all of this big chunk of muscle right there is called the ciliaris so what is this big chunk of muscle right here this big chunk of muscle here is called the ciliaris all this right here this is called the ciliaris okay so the ciliaris muscle what is it doing what happens is it's actually I'm going to show you here in a second it's connected to the lens right so it when it contracts it changes the shape of the lens okay here's another interesting point here the ciliaris muscle is under two different types of inovation it's under parasympathetic nervous system inovation and sympathetic nervous system inovation we'll talk about this in more detail when we do What's called the pupilary light reflex which involves the accommodation reflexes too but the silarus muscle is involved in What's called the accommodation so we can even put that which is basically this changing in the shape of the lens so accommodation right these accommodation reflexes which is important for distance vision and close Vision all right just to give you a tiny little tidbit whenever the ciliaris muscle contracts so here I'll put it like this parasympathetic nervous system it actually will cause the ciliaris muscle to contract when it contracts you see these little things right here these little black lines they look kind of like strings from a guitar these things right here are called you can call them two things you can call them ciliary zonals so you you can call them ciliary zonals or you can just call them like suspensory ligaments suspensory ligaments what's why these are important is because when the ciliaris muscle contracts these weirdly these ciliary zonals become very loose and when they become very loose what happens is this lens starts bulging so it actually starts bulging and when it bulges that's for a very very close Vision so short distance Vision but if the ciliaris muscle relaxes so because of what system this would be the sympathetic nervous system the sympathetic nervous system actually relaxes the ciliaris muscle so it relaxes it if it relaxes it weirdly The sary Zone will become really tight and when they become really really tight it actually causes this lens to flatten and when the L lens flattens that's for very far distance Visions we'll talk talk about that when we get into the um specifically the pupilary light reflex okay just introducing a piece of it now all right cool now what's the other part so we got the iris we got the ciliaris there's these little cells here okay you see these tiny little cells here that's kind of lining right over the ciliaris muscle so there's some cells right here and there's some cells right here these little bad boys right there these are called your ciliary processes so what are these little structures they're called they're called your ciliary processes and they're a tiny little layer of epithelial cells so they're a tiny little layer of epithelial cells epithelial cells some sort of cuboidal epithelial cells right and what they do is they secrete that humor that aquous humor so they secrete what's called that aquous humor okay so look what happens here they secrete this humor right so they're going to be making this aqueous humor because there's going to be nearby blood vessels right so they're going to be having blood vessels serving this area so if you imagine here for just a second let's say I remove out this part here and I put a little blood vessel in here because there's going to be blood vessels running all in this area it gives off little connections all right it gives off little connections and what happens is these ciliary processes could take some of the substances from the blood and make this aquous humor now what happens is is this aquous humor and these cells could be over here too right so they could even have some lining this side too I'm just showing it here what happens is let's actually kind of bring this stuff up here it moves upwards and as this aquous humor starts moving it actually comes up through the back of the iris Right comes up the back of the iris and then it moves through this little hole here what is this hole here called the pupil and it moves into this little chamber right here which we're going to talk about later and then from here it can provide some certain types of lubrication to to different structures in that area and can pick up metabolic waste and it can drain into this little hole right here that hole is called the canal of slim or schlim or you can I like to call it the sclero venosus because it just sounds weird sounds like I'm saying something like I shouldn't be saying right so again this structure here is called the scleral Venus sinus or the canal of schlim okay and so again what happens these ciliary processes are making this humor moves up through the you know there's actually a chamber here I'll mention it now I might as well cuz I'm already talking about what is this chamber here there's two Chambers here there's a chamber here and a chamber here this whole thing though if I were to make this whole distance here let's do this in pink so it's nice and bright here this whole distance here from the cornea all the way to the lens so from the cornea all the way to the lens there is a specific this whole thing is a segment what is this segment here called this segment is called the post I'm sorry posterior there should be anterior segment anterior segment now there's two chambers of the anterior segment separated by the iris this chamber back here is called the posterior chamber and then this one right here is actually called the anterior chamber now truthfully it's hard to show it in this this diagram here but what happens is this lens is actually much much closer here and the ciliary process is whenever they're secreting this this acre humor what happens is the sary's muscle has to contract to kind of move the shape of the lens a little bit so that this aquous humor can move underneath the lens and then from the posterior chamber it moves into the anterior chamber through the pupil then from that it goes into the anterior chamber and moves from the anterior chamber and drains into this area here this little hole here called the scarel Venice sinus or the canal schlim okay just so that we got that so the flow of vacuous humor sary processes are secreting this humor it moves kind of underneath the lens because the silary muscles have to actually control that the accommodation reflex to allow for it to move underneath the lens then it moves through the pupil hole it moves from the posterior chamber into the anterior chamber through that pupil hole and then it drains into the Scaro Venus sinus alrighty sweet deal okay so let's just recap this real quick because we basically covered these parts here we got one more layer but again Scara has episclera Scara proper and lamin fusa and if I'm being very specific to kind of go along with this how I said that the corny you had an outer layer to Inner layer this would be the same thing so from Outer to Inner layer we're moving downward so the outer layer is the episclera then the middle layer is the Scara proper and then the middle innermost layer is going to be the lamina fusa all right sweet now let's go to the next part of the uvia or the vascular tunic one more part here all right so this posterior extension that's coming from the C body see this posterior extension here that's moving all here this maroonish like structure here this is all called the choroid it's called the choid so what is this structure here called this structure here is called the [Music] choroid now the choroid is important because the chid is actually going to be a very pigmented membrane so it's a pigmented membrane now I'm mentioning that because that has a important physiological function when light rays because you know light rays is coming from many many different directions through here when the light rays are coming out here and they could be hitting different parts of the retina this light rays could actually be scattered throughout the I which can cause different problems with vision right we don't want that we don't want this actual light to be scatter to through all different areas because it could affect the visual field processing so what happens is the choroid absorbs some of those light rays that are being reflected okay so what is this guy doing here what is this choid doing he's basically absorbing any light rays to prevent reflection and scattering of light because that could affect the actual visual pathway and what we see within our visual fields we don't want that also really important I'm going to do it in red it has a nice vascular Supply a lot of blood vessels that are running in this area Okay so it has a nice little vascular Supply okay so a very rich in vascular Supply which is going to nourish a lot of different structures including the retina so it's actually going to have a nice vascular Supply that can give blood supply to the retina and it's going to be a pigmented membrane which can absorb a lot of different light rays to prevent that refle reflection of that light and the scattering of those light rays so that we have very very uh very precise and very very good visual pathway without any different types of uh you know Illusions or anything that could come from it okay all right sweet so we covered that now all right now let's move on let's get rid of these light rays here let's move on to the next part what's the next part so we've covered what we've covered the fibers tunic this part's done here we covered the vascular tunic that part's done there now we're going to cover the sensory tunic so the sensory tunic which is actually going to be consisting of the Rea and we said that we wanted to talk about something else here all right if you look here we were going to talk about this vitus humor from here if you look here from the back of the lens go from the back of the lens the posterior part of the lens all the way back to the retina okay so all the way back to the retina this whole thing makes up another segment so the anterior segment was from the anterior part of the lens to the cornea this segment the posterior segment is going to be from the posterior part of the lens all the way back to the red now I talked about shame on me I talked about the sary zonals and dispensary but I didn't really talk about the lens I said that it's important for basically helping to refract light rays and helping to control our distance vision and our short like close Vision but I didn't really talk about it enough so let me actually just real quickly talk about this this is actually the lens right now what's important about the lens we said it's responsible for refracting light rays so whenever light is coming in here it helps to be able to bend the light right and helps to be able to allow for the to focus those light rays specifically onto the retina so it's helping to refract these light rays okay so that's one of his functions But the lens is actually made up of different things if I were to say here we have the lens there's actually two components of the lens the lens is actually consisting of what's called crystallin like protein molecules they call them crystallins which are just proteins and that makes up what's called the lens fibers so the lens fibers is actually going to be made up of crystallin proteins and then you have another component which is called the lens epithelium epithelium and this is actually going to be consisting of some like a cuboidal epithelial tissue cells so it's actually going to have a little bit of cuboidal cells okay so this cuboidal cells so this is important to understand that the lens is actually made up of two things what is the lens made up of it's made up of lens fibers and lens epithelium okay two components here the reason I'm mentioning this with this whole lens fibers and the crystallin proteins is because in certain situations there is a uh you probably heard of it called cataracts they're called cataracts and cataracts are basically just accumulation or clumps of these crystallin proteins uh you know and cataracts can be due to many things one of the common causes is diabetes so in people who have diabetes this could actually be a cause smoking actually accelerates this process and what else it could even be congenital right so sometimes just congenital you know another weird one it's it doesn't make any sense but it could be due to if you consume too much vitamin C so if you take too much vitamin C like through supplementation I actually take Vitamin C that's why it's weird if if you actually take too much vitamin C this could actually accelerate the process of cataracts too so it's a unfortunate thing here right so that's why I'm mentioning the lens is because there is certain clinical correlations that whenever there's accumulation of these crystallin proteins it can cause cataracts which can definitely make a huge difference in Your Vision because what is it was responsible for helping to refract some of those light rays onto the retina to focus those light rays onto the retina to help within our our distance vision and our close-up Vision okay and you can actually do surges to replace the actual uh lens nowadays so that's pretty cool all right so we covered the lens now let's get back to the posterior segment sorry for being off track there okay now in the posterior segment it's going to be made up of all of this pink stuff now what's interesting about this pink stuff here is that you make it during embrionic development and you never make any more of it for the rest of your life whatever you have that's what you got forever so what is this jellylike material here called which it has some types of proteins also within it as well as other different types of molecule like hyaluronic acid and stuff like that what is this substance here called this whole substance pretty much occupying the entire posterior segment is called the vitous humor so the pretty much this whole posterior segment is occupied by the structure called the vitous humor there's actually a Remnant like structure that can actually run through here called the hyoid Canal we're not going to mention it but it can actually uh run right within the v's humor we're not going to talk too too much about it just saying that there is another structure that can run in it the posterior segment which is called the hyoid Canal but primarily it's going to be made up of this vitous humor now what's the function of this vitous humor what does it do well the vitous humor is really good at being able to transmit the light rays so it's good at transmitting the light rays so any light rays that are coming in here this vitous humor is very very very good at being able to allow for the light R to move through that jelly-like material and onto the retina also it's very kind of like a a strong jelly like material so it actually you see how right here we have this like black lining here this black lining here with all this like baby blue underneath it all this part here the black line all the way back to that Brown Line there this is going to be made up of the neural layer of the retina so we'll talk about these two things there's two parts of the retina the inner neural layer of the retina and the outer Pig layer of the retina what this actual vitous humor does is it holds the retina together so it holds the retina the neural layer and the pigmented layer close to one another okay so it holds the neural layer and the pigmented layer close to one another that's another function so it holds retina in place and know another thing that we didn't really talk too much about but we talked about in other videos you know what's actually connecting over here on the eye like for example let's say that I have a muscle right here the inferior rectus let's say that I have a muscle back here up here I mean superior rectus and then you have other ones medial rectus lateral rectus all those different muscles right what are they doing they're called extraocular eye muscles and they're changing you know they're moving the eyes whenever these extraocular muscles are Contracting and pulling on the eyes they can change the intraocular pressure but you know the vitous humor is very very good at doing it's helping to maintain it's contributing to the intraocular pressure to prevent any excessive changes in the intraocular pressure that is occurring whenever these extraocular muscles are Contracting so again one more time when the extraocular muscles are Contracting the vitous humor helps to be able to maintain the actual intraocular pressure that's its function when the extrinsic ocular muscles are Contracting it helps to maintain the intraocular pressure so we can say it contributes to I'm going to put in inra ular pressure IOP okay so it contributes to intraocular pressure sweet now we get on to the freaking good stuff the meat and potatoes all right so let's talk about this one right here we're going to actually zoom in on later when we go through the layers of the retina but I'm just going to take a tiny little piece out for just a second here so let me pretend that I'm doing this for a second I'm taking a slice of this a little chunk of this right here and I'm going to zoom in on it okay I'm going to take a little chunk of that and I'm going to zoom in on it so let's come over here for just a second all right so let's say right here let's say that this is that actual part there and that was kind of separating what would this structure be right here this would be where the vitous humor is so let's say this is where the vitous humor is okay that's all vitous humor then there was the part of the retina that we had here in blue all this part here what is this made up of what is the retina made up of we'll go over its cell layers in more detail but I'm going to give you a brief little discussion minute very very brief this is the outer pigmented layer of the retina there's two parts of the retina okay what is this blue layer here called this blue layer is the inner neural layer of the retina the neural layer of retina this is made up of three different types of cells well there's actually more we'll we'll discuss these in more detail like I said but there's going to be what's called called photo receptors photo receptors and these are like your rods and your cones there's going to be what's called bipolar cells or bipolar neurons there's going to be what's called gangon cells and then there's going to be what's called Amrine and horizontal cells which are basically helping to modify the the visual pathway so a lot of different cells within this area that are making up this neural layer of the retina photo receptors which you can consisting of rods and cones bipolar neurons gangon cells and Amrine and horizontal cells this is important because we talk about phototransduction we'll see this flow okay so that's make up in the neural layer of the retina the next one that we said this brown layer is the outer pigmented layer of the retina so this is the outer pigmented layer of retina and this is actually made up of these actual epithelial cells these epithelial cells it's actually made up of epithelial cells kind of like a single layer of epithelial cells rich in melanin very rich in melanin and that is important for basically being able to help to contribute to preventing the scattering of light Ray so it absorbs some of that light to prevent the scattering and the actual reflection of these different types of light rays another thing what do we say it runs right around this area the choid so the choid runs in very very close proximity to this actual outer pigmented layer why is that important because you see these epithelial cells that are actually rich in me melanin we call them um pigmented epithelial cells these pigmented epithelial cells they basically act like uh kind of like the part of the bloodbrain barrier in a similar way these cells here they filter whatever is actually coming out of this choid V vessels and determine what actually goes into the retinal area Okay so these cells here that are making up this outer pigmented epithelium they're very special and the reason why is they're controlling what's leaving the blood from the choid vessels and coming out here into the neural layer of the retina the reason I'm mentioning this is because in certain types of severe trauma or shifting of movement you can actually kind of dissect this layer here kind of dissect this layer right here and when you dissect this layer right here what can happen is some of this vitous humor can actually leak in between these spaces so some of this vitous humor can leak in between these spaces when some of this vitous humor leaks in between the actual neural layer of the retina and the outer pigmented layer of the retina that's called a retinal detachment and if not treated very quickly it can lead to blindness okay so in certain situations in which there is the separation of the internal layer of retina and the outer pigmented layer of the retina Vitus hum can come into that little space and cause retinal that's a retinal detachment and if not treated quickly it can lead to blindness all right that's that part one other thing I want to mention here let me actually get rid of this part here because I want to mention something else with relation to the eye I'm going to draw another mini eyeball here real quick another mini eyeball because I want to talk about these things called your eyelids your palra so let's see here I draw another mini eyeball here's the actual Cora here's the pupil and then here's your optic nerve right we're not going to draw everything in there it's not super important ah freck it we'll do it real quick do this here and then that there okay now coming right around this area you're going to have the lower eyelid so you're going to have a little area right here called the lower eyelid then coming over here we have another one which is going to be the upper ey let's actually make this one look like that one let's actually do it like this okay so look you'd have some beautiful eyelashes coming off there and some beautiful eyelashes coming off like that right why am I mentioning this two things one there's a little layer here let's do this one in Orange o orange there's a little layer here lining right underneath this thing what do we call this we call this the palpa so this is the inferior palpa the lower eyelid this is the superior palpa the upper eyelid there's a little tissue here that's lining not only the eyelid but it's giving off a little double layered membrane here that kind of covers a little bit of the Cora okay so there's a little layer here that's actually covering underneath the palpar and then there's a layer that's actually covering onto the bulb of the eye here a little bit on the bulb of the eye so again same thing over here there' be a little layer here covering the inner surface of the palpar and then giving off a little layer here that kind of covers a little piece of the Coria like the bulb of the cornea right what is this called This is called the conjunctiva all right so this part here that part there that's actually lining the inner part of the palpa that's called the palpal conjunctiva palpal palpa brl conjunctiva and then this inner one here that's actually lining the little parts of the cornea there that's called the bulbar conjunctiva okay the bulbar conjunctiva the reason why I'm mentioning that is that certain bacteria or viruses can accumulate in this area people always joke around and say like oh dude I'm going to fart on your pillow and you're going to get pink eye it's partially kind of true if certain types of bacterial molecules or viral molecules get into that little space there and cause inflammation and infection of that area that can lead to what's called conjunctivitis pink eye right that's why it's important to little know a little bit about that is that if there's the inflammation of the Papo conjunctiva and then the bulbar conjunctiva this could lead to what's called pink ey or conjunctivitis all right so don't go farting on people's pH pillows and stuff all right now next thing there's another two more important structures in here right in here if I kind of draw in Black here there's a little plate a little plate right here it's called the tarsel plate so what is that little thing I'm making like a u that's called the tarel plate this has two functions one function is there's two muscles that connect to it one muscle is called the the actual the palpa muscles right so for example you could have the palp muscles if there's one up here that' be a connection of the levator palpa superioris also it's also a nice connection for the orbicularis oculi so two different muscles can attach to the Taro plate right so if I kind of draw it like this over here too let's say I draw it like this I bring it like this right here right there's a tarel plate right there and again there you have the levator Papa Superior is attaching and then the orbicular is oculi attaching okay that's one function of the Taral plate all right so there's two muscles that are attaching to the tarsel plate one could be the orbicularis oculi and if we were to be really specific there would be another one that's actually attaching up here called the L levator palp superioris okay so this one up here would be the levator palp I'm not going to write all levor palp Superior all right that's one function of the Taro plates another function there's these actual glands in here called the tarso glands so there's glands kind of like inside of that tarso plate there called called the tarso glands what happens is these are basically like sebaceous glands and they produce kind of like oily secretions on the eyelid to keep the eyelid and some of the structures on the eye nice and moist and prevent basically the eyelids from sticking together or sticking to the eye okay or the cornia in this case so there's little Taro glands inside of the Taro plate that producing sebum an oily secretion to basically keep the palpa nice and lubricated prevent them from sticking together and prevent it from sticking to like the corneal area okay all right guys I just wanted to take in a little bit of time and pre-draw this structure here because I want to talk really briefly about the lacrimal flow okay because that's kind that's kind of important so laa flow are basically the production of Tears which is what Conor McGregor is going to be doing when he fights Mayweather on August 26th all right anyway what happens here if we look at an anterior view of the eye here's your um upper palpa the superior palpa here's the inferior palpa you see this kind of like V like part here that v- like part there is actually called the lateral commissioner and this part over here is actually called the medial commissioner but don't get that confused with the space between the superior paler and the inferior paler that's actually called the pal feser okay so this little V part over here is actually called the lateral commissioner V part over here is the medial commissioner and the space between the palpar is called the palpal Fisher now this right here is the eye I'm just showing an anterior view of the nose like this is the nasal sep and this is the lateral wall of that nose and this is the lateral wall of that nose Okay that side of that nose all right sweet so let's go here in a step-by-step process first thing is the lacrimal glands if you remember the facial nerve the facial nerve cranial Nerf 7 cranial Nerf 7 was actually one of the big guys there that was going to inovate this guy right and caused this actual lacrimal gland to start producing lacrimal fluid and that lacrimal fluid if you remember it comes out and moves across the eyeball so it moves across the eyeball nourishing the cornea and basically picking up any types of metabolic waste products and it starts moving medially towards that medial commissure there's actually a little fleshy part here a little fleshy part here actually called the lacrimal corle a little area right there called the lacrimal corle little fleshy part there what happens is there's these tiny little holes here tiny little holes right there around that medial commissure called the lacrimal Puna so the first step is it lacrimal glands secrete it they move medially then the third step is they move into this holes here called the lacrimal Puna then from there they move to these tiny little canaliculi called the lacrimal canaliculi then from that they move into this big Old Sac here called the lacrimal Sac then the lacrimal Sac empties this stuff through this duct here called the naso lacrimal duct and it goes under underneath you see how this is the superior con Superior nasal cone middle nasal cone inferior nasal cone and in between it this is the superior meatus middle meatus and inferior meatus the nasal lacrimal duct empties in just around the inferior meatus into the nasal cavity okay so to recap that what's it all doing here first one lacrimal gland secretes okay fluid second step moves across cornea medially then third step what goes into the lacrimal Puna moves into lacrimal Puna then fourth step goes through these tiny little canaliculi then it goes into the lacal canaliculi then from there it goes into the lacrimal Sac then from there it goes into the nasal lacrimal duct and then from there goes into the nasal cavity through the inferior meatus so I'm going to put inferior meatus of nasal cavity holy sweet goodness we did it all right now one more thing I want to talk about and then we're going to go ahead and stop all right there's another little thing that I forgot to mention here probably probably one of the more important things here is that if you're looking here you see this whole big sucker right there what do you think this is this right here is called the optic nerve okay this is called the optic nerve so what is this structure here called it's called the optic nerve or cranial nerve two this is also called cranial nerve 2 the reason why I'm telling you that is because if we look at the eye if you do like it's called opthalmoscope so you look at the eye from actually doing an opthalmoscope you look into their eye you're going to see in the back of the eye you're going to see this structure here called the optic disc that little part there the optic disc is where the actual optic nerve is piercing through the back of the Scara then you'll see kind of a little bit near it you'll see another structure called the macula right where the fob and tralis where the highest concentration of cones are okay but right here is the optic disc so if I do what's called a fundoscopy where I'm looking at the back of the eye there's the optic disc and then there's What's called the macula ludia kind of a little bit more lateral to that the optic disc is where the actual optic nerve pierces through the back of the Scara now when I say piercers through the black of the scare we we said oh wait I thought the scare was the episer the Scara proper the lamin ausa yeah it gives a little extension downwards here and whenever the optic nerve is piercing through the back it moves these little holes so the optic nerve which the axons of the gang gland cells they're moving through these holes what are these holes here in the Scara called these holes in the Scara are called the lamina kosa cribrosa okay and it's running these little holes within the scare where the optic nerves are piercing through the back all right all right Niners we covered a lot of information this video I I really hope you guys enjoyed I hope it made sense if you guys did like it please hit the like button comment down in the comment section and please subscribe in the next video we're actually going to take a look more specifically at the retina zoom in on the retina all the cells of the retina and then talk about the photo transduction process I hope to see you guys there all right Ninja nerds until next time