Special Senses | Anatomy of the Eye

I'm engineers in this video we're going to talk about the structure of the eyeball alright so let's go ahead and get started with this because it's important before we start going into all the phototransduction and going into the retina 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 ok let's go get started so what are we going to try to cover in this video let's come over here look at our little outline setup first thing we're going to talk about is the tunics of the eye ok then I want to talk about these things called segments like anterior segments and posterior segments and once that braids then what's in them then after that we're going to talk about the flow of this substance called aqueous humor you know we might even throw in another thing called the lacrimal flow ok 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 alright so it's going to start about tunics so there's actually going to be three main tunics of the I 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 is made up of two things okay so the fibrous tunic is made up of two things one of them is going to be the sclera and we'll talk about the sclera and the other big component is actually going to be the cornea again the other one's going to be the cornea so the fiber is tunic we're going to talk about is actually gonna be made up of two things one is the sclera and the other one is the cornea then after that we'll talk about what's called the vascular tunic or the lluvia okay the vascular tunic sometimes they even call it the uveal lluvia alright we'll talk about that and this is made up of three different components right so this is was called the choroid which is a nice dark pigmented membrane that it's important for basically preventing the scattering and of light by absorbing that because it contains a lot of melanin in that area also there's a lot of blood vessels so it gives a nice good vascular supply to some of the layers of the right now okay then there's going to be what's called the iris and the iris is important for being of control specifically the pupil hole size 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 silly Aris 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 gonna 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 vitreous humor because it's kind of in that area but it's more of what's called us 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 fibers tunic which is made with a square and the cornea let's start with that first where would you find the sclera in here and what is the sclera made of all right so if you look here we're going to have this outer part of the guy 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 they actually kind I'm not going to go through every single component of each one but I'm going to say that there is three layers to the sclera so if we actually have this sclera here there's actually three layers of this Claire one is called the EPI sclera so that's the outermost part of the sclera and it's made up of a really nice dense fibrous connective tissue all right very rich and dense fibrous irregularly tissue then underneath that you're actually have another one it's called the sclera proper and the sclera proper is also important because the sclera proper is actually going to give a lot of collagen so a lot of collagen fibers so it makes it very tough right very very resilient and the last one that actually in do is called the lamina Fuca 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 lam on a few ska and then you're going to have the EPI sclera the sclera proper and William and a few skull right so there's three layer sets glare and it's a really really important layer and again it's made of like an opaque connective tissue there is clinical correlations this because sometimes in certain situations like jaundice certain bilirubin types of molecules can accumulate within the scelera and it can actually cause off like a nice little jaundice like color they say right so you can actually see them to sclera and also very very prevalent and people have what's called Gilbert's disease which is basically they produce too much bilirubin and accumulates there alright anyway that's the square 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 right 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 never believe it it's actually with about five layers it's five layers just to make it really simple there's one two three four five there's an epithelial layer and this is actually probably 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 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 epithelia is actually rich in not a lot of what's called noisy acceptors or pain receptors okay so it's also rich in a lot of what's called noisy acceptors or pain receptors why is this important because you know whenever you have something irritating the cornea what you're going to want to do it there's irritation of the coroneted is going to be sending signals because you want to blink right so we have pain receptors there to help us to let us know if there's any type of ear to the cornea also you're going to have other layers but underneath they're not super super and simp 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 of 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 stroma layer the Desmond's membrane and there's also one more layer called the endothelial layer okay all right now what's interesting about the coin is that it doesn't really have a lot of blood supply okay 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 corneal transplants you can actually do a corneal transplant from one person to another without having into the projection because there is no immune molecules in that vicinity really okay so again the coin is made up of five layers epithelial layer Bowman's membrane stroma 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 it a little bit of blood supply coming here near the endothelial layer okay to give a little bit of nutrition to the actual layers around this area okay all right so that's the cornea what is important about the cornea you know the coin 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 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 rates to pass through okay so that's one function the cornea it allows for light rays to pass through all right sweet so we've gotten a part of the fiber student which is made up of sclera 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 choroid the IRS and the ciliary body which is made up of the ciliary and the ciliary process let's talk about that okay so let's start here first with this big old maroon 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 like this let's say here's the pupil which is a hole between iris like this right here this is actually the pupil right here it's a little hole between the IRS right around that 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 pupil a okay so one of them is called I think that's actually I put the pup away let's put the pupil a so the die later shoot delay another one is going to be what's called the sphincter pupil a the reason why I'm mentioning this is because the dilated pupil a is underneath what's called sympathetic nervous system innervation where is the sphincter pupil a is underneath parasympathetic nervous system innervation so what do I mean here if the dilated pupil a is activated it'll cause the actual iris muscle to relax which will cause what what it will do to the pupil whole 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 causing that dilation of the pupil that's the job of the dilated pupil eh okay but let's say for whatever reason the parasympathetic nervous system fibers are innervating the sphincter pute delay and it's causing the actual iris to contract and constrict that pupil whole and it's acting like a sphincter that's called the sphincter pupil eh okay so again dilated pupil a dilates the pupil shrink your pupil a constrict the pupil simple as that and again it's made up of a nice muscular layer so it's made up of the muscle there right the dilator and the constrictor but you know what else is in poor 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 determining these darker colors just the accumulation of more of this actual pigments even when actually we were born most of us almost all of us are born with like kind of like a slate gray or blueish pigment right and then over time the actual real pigment of our actual iris comes out okay all right 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 it's called the silly eros so what is this big chunk of muscle right here this big chunk of muscle here is called the silly eros all this right here this is called the silly eros okay so the ciliary muscle what is it doing what happens is it's actually imma show you here in a second it's connected to the lens all right so it when it contracts it changes the shape of the lens okay here's another interesting point here the ciliary muscle is under two different types of innervation it's under parasympathetic nervous system innervation and sympathetic nervous system innervation we'll talk about this in more detail when we do what's called the pupillary light reflex which involves the accomodation reflexes too but the ciliary muscle is involved in what's called the accomodation so we can even put that which is basically this changing in the shape of the lens so accomodation right these accomodation reflexes which is important for distance vision and close vision all right just to give you a tiny little tidbit whenever the ciliary muscle contracts so here I'll put it like this parasympathetic nervous system it actually will cause the ciliary muscle to contract when it contracts you see these little things right here these are the black lines they look kind of like strings from a guitar these things right here called you can call two things you can call me Eli Aires O'Neill's she didn't call them ciliary zonules or you can just call them like suspensory ligaments suspensory ligaments what's implied ease are important is because when the ciliary muscle contracts these weirdly these silly Arizonians 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 it's a short distance vision but if the ciliary muscle relaxants so because of what system this would be the sympathetic nervous system the sympathetic nervous system actually relaxes the ciliary muscles so it relaxes it if it relaxes it weirdly distill areas only will become really tight and when they become really really tight it actually causes this limbs to flatten and when the lens flattens that's for very far distance vision so we'll talk about that when we get into the specifically the pupillary light reflex okay I'm just introducing a piece of amount all right cool now what's the other part so we've got the iris we got the silly eros there's these little cells here okay see these tiny little cells here that's kind of lining right over the ciliary 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 so I'm sort of cuboidal epithelial cells right and what they do is they secrete that humor that aqueous humor so they see create what's called that aqueous humor okay so look what happens here they see create this humour 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 it 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 aqueous humor now what happens is is this aqueous humor and it sells to be over here too right so they can 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 aqueous 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 does this hold here call 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 different structures in that area it can pick up metabolic waste and it can drain into this little hole right here that hole is called the canal of slim our schlimm where you can I like to call the scleral Venice science 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 venous sinus or the canal of schlemm okay and so again what happened the ciliary processes are making this aqueous humor moves up through V you have it's actually a chamber here I'll mention it now I might as well cuz I'm already talking about what is this chamber you 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 as 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 diagram here but what happens is this lens is actually much much closer here and the ciliary processes whenever they're secreting this is aqueous humor what happens is the ciliary muscle has to contract to kind of move the shape of the lens a little bit so that this aqueous 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 freeing anterior chamber and drains into this area here this little hole here called the scleral Venice sinus or the canal of schlemm okay just so that we got that so flow of a consumerist ciliary processes are secreting this humor it moves kind of underneath the lens because the ciliary muscles have to actually control that the accommodation reflects 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 scleral venous sinus all righty sweet deal okay so let's just recap this real quick because we basically covered these parts here we got one more layer but against Clara has epi scelera sclera proper and lamina whew ska and if I'm being very specific to kind of go along with this how I said that the cornea had an outer layer to enter layer this would be the same thing so from outer to inner layer we're moving downwards so the outer layer is the Epis Clara then the middle-earth is Clara proper and then the middle innermost layer is going to be the lamina phew scone all right sweet now let's go on to the next part of the lluvia or the vascular tunic one more part here all right so this posterior extension that's coming from the ciliary body see this posterior extension here that's moving all here this maroon ish like structure here this is all called the choroid it's called the choroid so what is this structure here called this structure here is called the choroid now the cool root is important because the chorion 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 ion which can cause different problems with vision right we don't want that we don't want this actual light to be scattered to do all different areas because it could affect the visual field processing so what happens is the colloid absorbs some of those light rays that are being reflected okay so what is this guy doing here what is this colloid 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 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 there's a nice little vascular supply okay so very rich in vascular supply which is going to nourish a lot of different structures including the retina so it's actually 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 to prevent that refract the reflection of that light and a scattering of those light rays so we have very very very precise and very very good visual pathway without any different types of you know illusions or anything that could come from it okay all right sweets we covered that now all right now let's move on 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 parts done here we cover the vast of the tunic that parts done there now we're going to cover the sensory tunic so the sensory tunic which is actually going to be consisting of the retina and we said that we wanted to talk about something else here alright if you look here we're going to talk about this victress humor from here if you look here from the back of the lens go from the back of the lens the poster part of 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 retina now I talked about shame on me I talked about the ciliary zonas and Spencer aliens 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 click 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've 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 focus those light rays specifically on to the retina so it's helping to refract these light rays okay so that's one of its 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 crystalline like protein molecules they call crystal ins which are just proteins and that makes up what's called the lens fibers so the lens five is actually going to be made up of crystalline 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 cuboidal epithelial tissue cells so it's actually gonna have a little bit of cuboidal cells okay so it can cuboidal cells so this is important to understand that the lens is actually made up of two things what if 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 crystalline proteins it's because in certain situations there is a you probably heard of it called cataracts they're called cataracts and cataracts are basically just accumulation or clumps of these crystalline proteins you know and cataracts could be due to many things one of the common causes diabetes some 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 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 you actually take too much vitamin C this could actually accelerate the process of cataracts too so it's a unfortunate thing right so that's why I'm mentioning the lens because there are certain clinical correlations that whenever there is accumulation of these crystalline 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 with in our distance vision and our close-up vision okay and you can actually do surgeries to replace the actual lens nowadays so that's pretty cool alright so we cover 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 embryonic 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 jelly-like 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 vitreous humor so the pretty much this whole posterior segment is occupied by the chakra called the vitreous humor there's actually a remnant like structure that can actually run through here called the hi lloyd canal we're not going to mention it but it can actually run right within the vitreous humor we're not going to talk too much about just saying that there is another structure that can run in it the posterior segment which is called the hi Lloyd canal but primarily it's going to be made up of this vitreous humor now what's the function of this vitreous humor what does it do well the vitreous 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 vitreous humor is very very very good at being able to lots of libraries to move through the jelly-like material and also the retina also it's very kind of like 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 right now 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 pigmented layer in the red now what this actual vitreous humour 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 another thing that we don't really talk too much about what we talked about in other videos you know what's actually connecting over here on the I like for example I 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 your other ones medial rectus lateral rectus all those different muscles right what are they doing they're called extra ocular eye muscles and they're changing you know they're moving eyes whenever these extra ocular muscles are contracting and pulling on the eyes they can change the intraocular pressure but you know the vitreous 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 extra ocular muscles are contracting so again one more time when the extra ocular muscles are contracting the vitreous humor helps to be able to maintain the actual intraocular pressure that's this function the extrinsic ocular muscles are contracting it helps to maintain the intraocular pressure so we can say contributes to I'm going to put intra ocular pressure IOP okay so it contributes to intraocular pressure sweet now we get on to the friggin good stuff the meat and potatoes alright so let's talk about this one right we're going to actually zoom in and 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 little chunk of this right here and I'm going to zoom in on it okay I'll take a little chunk of that and I'm going to zoom in on it 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 vitreous humor is so let's say this is where the vitreous humor is okay that's all vitreous 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 limb of discussion I'm 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 you call 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 discuss these in more detail like I said but there's going to be what's called photoreceptors photoreceptors and these 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 ganglion cells and then there's going to be what's called a Makran 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 photoreceptors are consisting of rods and cones bipolar neurons ganglion cells and amacrine horizontal cells this is important because we talked about phototransduction will 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 it's important for basically being able to help to contribute to preventing the scattering of light ray so it absorb 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 choroid so the colloid runs are 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 melanin we um pigmented epithelial cells these pigmented epithelial cells they basically act like kind of like the part of the blood-brain barrier in a similar way these cells here they filter whatever is actually coming out of this choroid best 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 colloid 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 or 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 vitreous humor can actually leak in between these spaces so some of this vitreous humor can leak in between these spaces when some of this vitreous humor leaks in between the actual neural layer of the retina and the outer pigmented layer the right now 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 inner layer retina and the outer pigmented layer of the retina vector semen can come into that little space and cause retinal did that's a retinal detachment and if not treated quickly it can lead to blindness alright 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 palpebral so see here I draw another mini eyeball here's the actual cornea 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 affricate 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 you'll have another one which is going to be the upper eyelid actually make this one look like that one 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 orange there's a little layer here lining right underneath this thing what do we call this we call this the palpebral this is the in fear powder bruh the lower eyelid this is the superior palpebral 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 the cornea okay so there's a little layer here that's actually covering underneath the palpebral 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'd be a little layer here covering the inner surface of the palpebral and then giving off a little layer here that kind of covers a little piece of the coin like a 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 bruh that's called the palpebral conjunctiva palpebral Palpa burles conjunctiva and then this inner one here there's actually lining the little parts of the cornea there that's called the bulbar conjunctiva you tell you the bulbar conjunctiva the reason why I mentioned has a certain bacteria or viruses can accumulate in this area people always joke around and say like oh I'm going to fart on your pillow and you're going to get pinkeye it's partially kind of true if certain types of bacterial molecules are viral molecules get into that little space there and cause inflammation and infection of that area that can lead to is called conjunctivitis pinkeye right that's why it's important to little I know a little bit about that is that if there's the inflammation the palpebral conjunctiva and then the bulbar conjunctive of this could lead to what's called pink eye or conjunctivitis all right so I'll go fartin on people's fill pillows and stuff all right now next thing there's another two more important structures in here right in here I kind of draw in black here there's a little plate a little plate right here it's called the tarsal plate so what is that little thing I'm making like a u that's called the tarsal plate this has two functions one function is there's two muscles that connect to it one loss was called the the actual the palpebral muscles right so for example you could have the palpebral muscles if there's one up here that'd be a connection of the leavitt or palpebrae superioris also it's also a nice connection for the orbicularis oculi so two different muscles can attach to the tarsal plate right so if I kind of draw like this over here to say I draw it like this I bring it like this right here right there's a torsional plate right there and again there you have the Leavitt or palpebrae superioris attaching and then the orbicularis oculi attaching okay that's one function of the tarsal plate all right so there's two muscles that are attaching to the tarsal plate one could be the orbicularis oculi and if we were to be really specific there would be another one that's actually catching up here called the Leavitt or palpebrae superioris okay so this one up here will be B Leavitt or palpebral I'm not going to write all at left or palpebrae superioris all right that's one function the tarsal plate another function there's these actual glands in here called the tarsal glands so there's glands kind of like inside of that tarsal plate they're called the tarsal 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 are the cornea in this case there's little tarsal glands inside of the tarsal plate the producing sebum an oily secretion to basically keep the palpebral 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 Kenny it's kind of important so lack of a flow are basically the production of tears which is what Conor McGregor is going to be doing when he fights employed Mayweather in August 26 all right anyway what happens here if we look at an anterior view of the eye here's your upper palpebral the superior palpebral here's the inferior palpebral you see it's kind of like V like part here that V like Park there is actually called the lateral commissure and this part over here is actually called the medial commissure but don't get that confused with the space between the superior popover an infinite number that's actually called the power refresher okay so this little V part over here is actually called B labra commissure V part over here is the medial commissioner and the space between the palpebral is called the palpebral fissure now this right here is the eye I'm just showing an anterior view of the nose like this is the nasal septum and this is the lateral wall that knows and this is the lateral wall of that nose okay that side of that nose all right sweet 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 nerve seven cranial nerve seven was actually one of the big guys there that was going to innervate 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 eyeballs 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 core uncle a little area right there called the lacrimal Cronk a little fleshy part there what happened is there's a tiny little holes here tiny little holes right there around that medial commissure called the lakum pumpka so the first step is that black immigrants secrete it they move medially then the third step is they move into this holes here called the lacrimal punctum then from there they move through tiny little canaliculi called the lacrimal can now lick you lie then from that they move into this big old sack here called the lacrimal sac then the lacrimal sac empties this stuff through this duct here called the nazo lacrimal duct and it goes underneath you see how this is the superior conk a superior nasal conchae middle nasal conchae inferior nasal conchae and in between it this is the superior meatus middle mediate it's an inferior me itís the nasolacrimal duct empties in just around me in fear me ate it 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 Punta moves into lacrimal punctum then four step goes to these tiny little canaliculi then it goes into the lacrimal canal lick you lie then from there it goes into the lacrimal sac then from there it goes into the nasolacrimal 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 you're 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 the structure you're called it's called the optic nerve or cranial nerve - this is also called cranial nerve - the reason why I'm telling you that is because if we look at the eye for if you do like it's called an ophthalmoscope II so you look at the eye from actually doing an ophthalmoscope you look into their eye you're going to see in the back of the eye you're going to see the structure called the optic disc that little part there the optic disc is where the actual optic nerve is piercing through the back of the sclera then you'll see kind of a little bit near it you'll see another structure called the macula right where the fovea centralis is where the highest concentration of cones are okay but right here is the optic disc so if i do what's called a fun no scoop you are looking at the back of the eye there's the optic disc and then is what's called the macula lutea kind of a little bit more lateral to that the optic disc is where the actual optic nerve pierces through the back of the sclera now when i say it pierces through the black of this glare we say go away I thought this Claire was the Epis Claire the sclera proper the lamina whew school yeah it gives a little extension downwards here and whenever the optic nerve is piercing through the back it moves these little holes to the optic nerve which should be axon to the ganglion cells they're moving through these holes where these holes here in the sclera called these holes and the sclera are called the lamina crib or OSA crib or OSA okay and it's running these little holes within a square where the optic nerves are piercing through the back all right all right measures we covered a lot of information in this video I really hope you guys enjoyed I hope it made sense if you guys did like it please hit the like button comment down the comment section and please subscribe and the next video we're actually going to take a look more specifically at the retina zoom in on the red all this the retina and to talk about the phototransduction process i hope to see you guys there all right ninja nerds until next time

Channel: Ninja Nerd

Views: 306,558

Rating: 4.9640503 out of 5

Keywords: special senses, anatomy of the eye, eye anatomy

Id: Hclc7lL_Oyw

Length: 45min 45sec (2745 seconds)

Published: Sat Jul 29 2017