🥇 Anatomía del OJO 2/3 - Túnica Media y Túnica Interna

Summary

Este video ofrece una visión detallada de la anatomía del ojo, centrando la segunda parte en la túnica media y la interna del mismo. La túnica media, compuesta por la coroides, el cuerpo ciliar y la iris, es esencial para la irrigación sanguínea del globo ocular. La coroides está formada por cuatro capas y se extiende desde el polo posterior del ojo hasta la ora serrata. El cuerpo ciliar, con forma triangular, está formado por músculo ciliar y procesos ciliares, y es fundamental para el enfoque y la adaptación del ojo. La iris, parte pigmentada del ojo, contiene dos esfínteres que controlan la contracción y dilatación del pupila. Por último, la túnica interna, la retina, se divide en tres partes: la retina propiamente dicha, la porción ciliar y la porción iris. La retina es transparente y es la estructura donde se captan las imágenes, siendo la mácula lutea una zona crítica para la visión detallada.

Takeaways

• 👁️ El ojo se divide en tres túnicas: la externa (tunica fibrosa), la media (tunica vascular) y la interna (tunica interna o retina).
• 🔍 La túnica media está compuesta por la coroides, el cuerpo ciliar y la iris, siendo la coroides la parte más posterior.
• 🕸️ La coroides contiene la mayoría de los vasos sanguíneos del ojo y está formada por cuatro capas, incluyendo la lámina supracoroidal, lámina vascular, capilaris y la membrana basal.
• 🔭 El cuerpo ciliar es una extensión anterior de la coroides, con forma triangular, compuesto por los músculos ciliares y los procesos ciliares.
• 👓 Los músculos ciliares son parasimpáticos y su收缩 (contracción) permite enfocar objetos cercanos al hacer la lente más redondeada.
• 🌈 La iris es la parte pigmentada del ojo que da la coloración característica y contiene dos esfínteres: el esfínter de la pupila (miosis) y el músculo dilator de la pupila (miriasis).
• 👀 La túnica interna o retina es la única estructura de la túnica interna, es transparente y es donde ocurre la transformación de impulsos luminosos en imágenes.
• 🔵 La mácula lutea es la región central de la retina donde la función visual es más aguda y no contiene vasos sanguíneos (es avascular).
• 🏥 La papila óptica es la zona por donde emerge el nervio óptico, y presenta una excavación central a través de la cual salen los vasos sanguíneos de la retina.
• 📐 La retina se extiende desde la papila óptica hasta el ora serrata, donde cambia su posición y cubre la parte interna del cuerpo ciliar y la porción iris.
• 🧠 La retina es considerada una extensión del nervio óptico y es esencial para la percepción de la visión.
• 📹 En el siguiente video se explorarán los músculos oculares y el aparato lagrimal, para comprender mejor la anatomía y función del ojo.

Q & A

¿Cuál es la estructura que compone la túnica media del ojo?

La túnica media del ojo está compuesta por tres partes: la coroide, el cuerpo ciliar y la iris.

¿Qué es la coroide y cuál es su ubicación en el ojo?

La coroide es la parte más posterior de la túnica media y se encuentra aproximadamente al nivel del polo posterior del ojo, cruzando incluso el disco óptico.

¿Cuáles son las cuatro capas que componen la coroide?

Las cuatro capas de la coroide son: la lámina supracoroidal, la lámina vascular, la capa de capilares (o choriocapilar) y la membrana basal.

¿Qué es el cuerpo ciliar y qué partes lo componen?

El cuerpo ciliar es la continuación anterior de la coroide y está compuesto por dos partes: el músculo ciliar y los procesos ciliares.

¿Cuál es la función del músculo ciliar?

La función del músculo ciliar es alterar la forma del cristalino para enfocar objetos cercanos o lejanos, un proceso conocido como la reflejo de acomodación.

¿Cómo se llama la parte del ojo que da color a las personas y está compuesta por pigmento?

La parte del ojo que da color a las personas es la iris.

¿Qué es el ángulo iridiocorneal y qué importancia tiene?

El ángulo iridiocorneal es la zona donde la iris y la cornea se encuentran. Es importante porque es donde se encuentra la ducto de Schlemm, que es responsable de la absorción del humor acuoso.

¿Cuál es la estructura que compone la túnica interna del ojo?

La única estructura que compone la túnica interna del ojo es la retina.

¿Por qué se dice que la retina es transparente a pesar de que en algunos libros se la describe como amarilla?

La retina es en realidad transparente y colorless, y se describe a menudo como amarilla solo por convención en algunos libros didácticos.

¿Qué es la papila óptica y qué contiene?

La papila óptica es la zona donde emerge el nervio óptico. Contiene un punto central conocido como la excavación central, a través de la cual salen los vasos sanguíneos de la retina.

¿Cómo se llama la región de la retina donde no alcanzan los vasos sanguíneos y es de color amarillento?

La región de la retina donde no alcanzan los vasos sanguíneos y es de color amarillento se llama mácula lutea.

¿Cuál es la función de la mácula lutea en la visión?

La mácula lutea es la región de la retina donde se encuentra la foveola central, que es la parte más sensible a la luz y responsable de la visión detallada y aguda en el centro del campo visual.

Outlines

00:00

👁 Anatomía de la túnica media del ojo

Este primer párrafo aborda la anatomía de la túnica media del ojo, que está compuesta por tres partes: la coroides, el cuerpo ciliar y la iris. La coroides es la porción más posterior, ubicada alrededor del polo posterior del ojo y cruzando el disco óptico. Es conocida por su alta concentración de vasos sanguíneos y su estructura en cuatro capas: lámina supracoroidal, lámina vascular con sus capas arterial y venosa, capa de capilares (choriocapilaris) y la membrana basal que toca la retina. El cuerpo ciliar es la continuación anterior de la coroides, mientras que la iris es la parte más delantera de la túnica media, responsable del cambio de tamaño del pupilo y controlada por músculos esfínter y dilatador, influenciados por el sistema parasimpático y simpático, respectivamente.

05:03

🏼 Estructura y función del cuerpo ciliar

El segundo párrafo se centra en el cuerpo ciliar, descrito como de forma triangular con su base dirigida hacia el pupilo. El cuerpo ciliar está formado por el músculo ciliar y los procesos ciliares. El músculo ciliar tiene fibras meridionales y circulares, y su función es esencial para el refuerzo de la lenteja al alterar la tensión de los ligamentos que la sostienen. Los procesos ciliares son estructuras que rodean la circunferencia del ojo, aproximadamente 70 en número, y están relacionados con el ligamento de la lenteja. La innervación del músculo ciliar es de tipo parasimpático, lo que desempeña un papel crucial en el proceso de lacomodación, permitiendo el enfoque en objetos cercanos al relajar los ligamentos y permitir que la lenteja tome forma biconvexa.

10:08

🌈 La iris y sus relaciones con la cámara anterior y posterior

En el tercer párrafo, se describe la iris como la parte pigmentada del ojo que da la coloración característica. La iris tiene una cara anterior que mira hacia la cámara anterior del ojo y una cara posterior que mira hacia la cámara posterior. La iris está insertada en su circunferencia más grande en el cuerpo ciliar y forma el ángulo iridiocorneal, donde se encuentra el ducto de Schlemm, importante para el drenaje del humor acuoso. La orilla libre de la iris forma el orificio pupilar a través del cual la luz ingresa al ojo. La iris contiene dos músculos: el esfínter del pupilo, responsable de la miosis (contracción del pupilo) y el músculo dilatador del pupilo, que se activa por impulsos simpáticos y causa la miriasis (dilatación del pupilo).

15:08

👀 La túnica interna y sus divisiones funcionales

El cuarto y último párrafo explora la túnica interna del ojo, también conocida como túnica nerviosa, que alberga la retina. La retina se extiende desde el nervio óptico hasta el ora serrata, donde se vuelve más estrecha. La parte posterior de la túnica interna es la retina propiamente dicha, que captura las impresiones luminosas y las transforma en imágenes. Se destaca la existencia de la papila óptica, donde emerge el nervio óptico, y la mácula lutea, una región amarillenta que no es vascularizada y contiene la fovea central y la foveola, la parte más sensible de la retina para la visión detallada. La retina también incluye la porción ciliar, que recubre la parte interna del cuerpo ciliar y es muy rudimentaria en su función nerviosa, y la porción irídica, que cubre la parte posterior de la iris y es aún más rudimentaria.

Keywords

💡Tunica media

La 'tunica media' es una de las tres divisiones principales de la pared del ojo. Está compuesta por la coroide, el cuerpo ciliar y la iris. Es conocida como la capa vascular debido a la presencia de una alta concentración de vasos sanguíneos que nutren el ojo. En el video, se discute cómo la coroide, la parte más posterior de la tunica media, contiene la mayoría de los vasos sanguíneos y cómo se extiende desde el polo posterior del ojo hasta el punto donde la retina se estrecha en la ora serrata.

💡Córnea

La 'córnea' es la parte transparente delantero del ojo que permite la entrada de la luz. En el contexto del video, se menciona que la córnea es parte de la 'tunica externa' o 'tunica fibrosa', y se destaca su importancia en la formación de la visión al permitir que la luz pase al interior del ojo.

💡Cuerpo ciliar

El 'cuerpo ciliar' es una extensión anterior de la coroide y es parte de la 'tunica media'. Se menciona en el video que tiene forma triangular y está compuesto por los músculos ciliares y los procesos ciliares. Su función principal es ajustar la forma del cristalino para enfocar objetos cercanos o lejanos, un proceso conocido como la reflexión de acomodación.

💡Iris

La 'iris' es la parte del ojo que da color al mismo y controla la cantidad de luz que entra en el ojo mediante el cambio de tamaño del pupila. En el video, se describe cómo la iris tiene una cara anterior que mira hacia la cámara anterior del ojo y una cara posterior que mira hacia la cámara posterior, y cómo contiene músculos que realizan la miosis (contracción del pupila) y la miorriasis (dilatación del pupila).

💡Retina

La 'retina' es la capa interna de la pared del ojo y es esencial para la visión, ya que es responsable de captar las impresiones luminosas y transformarlas en impulsos nerviosos que el cerebro puede interpretar. En el video, se discute cómo la retina se extiende desde la ora serrata hasta la papila óptica, y cómo incluye la mácula lutea y el foveola central, que son áreas críticas para la visión detallada.

💡Papila óptica

La 'papila óptica' es la zona donde el nervio óptico sale del ojo. Se encuentra en el centro de la retina y es un punto ciego en la visión debido a la ausencia de células fotorreceptoras en esa área. En el video, se menciona que la papila óptica es el punto de emergencia de los vasos sanguíneos retinianos y es una estructura importante en la examinación del fondo del ojo.

💡Mácula lutea

La 'mácula lutea' es una región amarillenta de la retina que se encuentra cerca de la papila óptica y es la zona de mayor agudeza visual. En el video, se aclara que la mácula lutea es avascular y contiene una excavación central llamada fovea central, que es la parte donde la visión es más aguda y donde se concentran las células fotorreceptoras.

💡Acomodación

La 'acomodación' es el proceso por el cual el ojo cambia la forma del cristalino para enfocar objetos a diferentes distancias. En el video, se describe cómo los músculos ciliares controlan este proceso al relajarse o contraerse, afectando la tensión de los ligamentos del cristalino y permitiendo que el ojo enfoque objetos cercanos o lejanos.

💡Vasos sanguíneos

Los 'vasos sanguíneos' son tubos que transportan la sangre en el cuerpo y en el video, se resalta su importancia en la nutrición del ojo, especialmente en la coroide, que contiene la mayoría de los vasos sanguíneos del ojo. Estos vasos sanguíneos son cruciales para proveer de oxígeno y nutrientes a las estructuras del ojo y para llevar away los desechos.

💡Órbita

La 'órbita' es la cavidad del cráneo que alberga el ojo. Aunque no se discute en detalle en el video, se menciona al final como un tema relacionado con la anatomía del ojo y es importante para entender el apoyo y la protección que ofrece al ojo y sus estructuras.

💡Apodo del nervio óptico

El 'nervio óptico' es el nervio que transmite la información visual del ojo al cerebro. En el video, se hace referencia a su papel en la formación de la papila óptica y cómo la retina es considerada una extensión del nervio óptico, destacando su importancia en la función visual.

Highlights

El vídeo presenta la segunda parte de la anatomía del globo ocular, dividida en tres videos.

Se discute la tunica media del ojo, compuesta por la coroides, el cuerpo ciliar y la iris.

La coroides es la parte más posterior de la tunica media y contiene la mayoría de los vasos sanguíneos del ojo.

La coroides tiene cuatro capas, incluyendo la lámina supracoroidal, lámina vascular y la capilaris.

El cuerpo ciliar es una extensión anterior de la coroides y está compuesto por los músculos ciliares y los procesos ciliares.

Los músculos ciliares son parasimpáticos y controlan el enfoque al alterar la forma de la lente.

La iris es la parte del ojo que da la coloración y contiene dos esfínteres: el esfínter pupilar y el músculo dilatador.

La retina es la única estructura de la tunica interna y es esencial para la visión, transformando impulsos luminosos en imágenes.

La retina se divide en tres partes: la porción retiniana, la porción ciliar y la porción iridea.

La papila óptica es el punto de emergencia de la nervio óptico y se encuentra ligeramente medial y superior a la mácula lutea.

La mácula lutea es una zona avascular y es la parte de la retina donde la función visual es más aguda.

La foveola central es la parte más profunda de la mácula lutea y es crucial para la visión detallada.

Los vasos sanguíneos de la retina son derivados de la arteria retiniana central y se dividen en ramos nasales y temporales.

La porción ciliar de la retina cubre la parte interna del cuerpo ciliar y tiene una función visual muy limitada.

La porción iridea de la retina está ubicada detrás de la iris y es la parte menos sensible y más rudimentaria de la retina.

El vídeo ofrece una visión detallada de la anatomía del ojo, destacando la complejidad y la importancia de cada estructura en la visión.

Se invita a los espectadores a suscribirse y seguir el canal para obtener más contenido sobre anatomía ocular y otros temas relacionados.

Transcripts

Hello, hello, welcome to a new easy anatomy video and today I bring you the second part

of anatomy of the eyeball, anatomy of the eye, remember that we are going to divide the eye into three

videos, this is the second, already in the video Previously we talked about the outermost tunic,

now we will talk about the middle tunic and the internal tunic here so you can see what we talked about

in the previous video, don't get lost, this was the sclera and the cornea that made up

the fibrous tunic or tunica externa , while today we are going to talk first about the tunica

media, which is composed of three areas: a more posterior one called the choroid, an anterior

continuation of the choroid, which is the ciliary body, and then what is the iris of the eye, that is

the tunica media also called tunica vascular and finally we will talk about the tunica interna which

has a single structure which is the retina that we will also touch on in this video. Let's

start then talking about the structures that are found in the tunica media, this tunica

media as I told you is made up of three parts that are the choroid, the ciliary body and the iris,

we are going to start talking first about the choroid, remember that this external layer that

is seen here as a flesh color was the tunica fibrosa, then came this blue one that was the tunica media,

this yellow one that would be the internal tunic, then this choroid or which is the most

posterior part of the tunica media goes to be more or less at the level of the posterior pole of the eye, it will cross and

even the optic disc. In fact, it is said that the choroid forms fibers that help form this

cribriform plate through which the second cranial nerve, which is the nerve, passes. optic, then

this middle layer remember that they call it vascular layers precisely because the choroid is where

most of the blood vessels that are responsible for irrigating the eyeball are located,

so something important about it is that its outermost layer is not attached The retina at this

point is only joined by connective tissue but is not strongly adhered to it. Now,

this choroid is going to reach above the level where the retina begins to be the ora

serrata, perhaps you do not know the term ora serrata yet, when I explained the retina to you you will see what

that structure is, the fact is that it is said that The choroid then goes down from the posterior pole of the

eye to the place where the retina forms the ora serrata, which is more or less this place where

you see that the retina is narrowing, which is the yellow that you see here,

from then on we We call the ciliary body, which is the second portion of the

tunica media, so what layers will this choroid have? This choroid will have four layers,

we will start from the most superficial layer, which is most in contact with the sclera, to

the deepest layer which is the one that would be in contact with the retina, then the first layer

would be the suprachoroidal lamina, this suprachoroidal lamina has pigment cells, it is the one

that will be in direct contact with what is the sclera, with What is this outer tunic,

then we are going to have a second next layer which is a vascular lamina, this

vascular lamina is this lamina that you see here that has the large blood vessels, it will in turn be divided

into two planes: a superficial plane which is going to be an arterial plane, these arteries

are given by the long posterior ciliary arteries as you can see here and these

would be the short posterior ciliary arteries, so see that these are long posterior

because you see that they have a longer course, while These are the short posterior ones,

so in addition to having that superficial plane that is arterial, it has a deep plane that is venous,

which are veins that are found in that layer of the choroid, this vein has a tortuous route

and ends in what are the famous vorticose veins, which are the ones that later end up

draining into the ophthalmic vein, is the second layer, then the vascular layer, then we continue in

depth, after the vascular layer we have a layer of capillaries that is next to what you

see here, which would be the choriocapillaris layer, I have also read in some texts with the name

choroidocapillary layer, which would be the same and finally the layer that is most in contact with the

retina, which would be the basement membrane, that is the sheet that would then be in direct contact

with the retina, these are the layers of the crown and we are now going to move on to its anterior extension

, which would be the ciliary body, so remember that the ciliary body is to go from the

more or less narrow part of the retina, which is the ora serrata, forward until it continues with the

name of the iris. See, as far as you see the mark, here it would be the choroid and from there on it

would be the ciliary body. and see that the ciliary body that is shaded here in red

continues with the iris to then finish this middle tunic. Let's elucidate then what

structure there is in this ciliary body, this is a more or less cut that we made in the eye, we are

seeing it from above, this would be the lens, this would be the iris, this would be the cornea,

this would be the sclera and see here this structure that would be the ciliary body, it is said that

the ciliary body has a triangular shape, a base that faces towards the medial part of the eye,

well let's say that it is looking towards the pupil, while the vertex of that pyramid is which

will then continue posteriorly with the choroid, so what is the

ciliary muscle composed of? The ciliary muscle is made up of two portions, sorry, the ciliary body is

made up of two portions, one is the ciliary muscle and the other is the ciliary processes,

together the muscle and the process are what form the ciliary body. Let's start with

the ciliary muscle, this ciliary muscle follows the same shape as the ciliary body, it is triangular

with a base that goes towards the pupil and a vertex that goes towards the choroid, so it will have

two groups of muscles, see that They have muscles that are more anterior, which would be the

groups of muscles that have radiated fibers, also called meridional fibers, and they have a

group of muscles that are posterior to these meridional fibers, which are the fibers that go

in a circular direction, those are the famous muscles. ciliary that right now I am going to explain to you what

their function is, now, the ciliary process, which are these structures that you see here shaded

in green, are structures that together when they make the circumference of the eye are approximately

a number of 70 and that They also have a pyramidal shape or a triangular shape, now, at the

base it is also towards the pupil and the vertex is the one that is in contact with the

ciliary muscle itself, these ciliary processes are separated from each other, remember that we add approximately

70 times some spaces called ciliary valleys or also called zonular spaces,

see in this vision so that they do not get tangled I have a posterior vision of what we were seeing

right now, that is, it is like me cutting the eye in a frontal plane and seeing it from back to front This

would be the lens, all these are the fibers that connect to the ciliary processes, which would be

these that you see here and that grab me in what is the lens, what you see

here would be the iris seen from behind and this would be the retina seen from behind, in this middle layer

that is here, which would be the layer or tunica media; So, if you look closer, these would be

the ciliary processes, more or less a number of 70. These spaces between them would be the

zonular spaces, and then see the ligaments that will later support the lens.

Now the innervation of these ciliary muscles is a parasympathetic type innervation, what

is the function? I explain to you, remember that the processes and places where the suspensory ligaments of the lens are connected,

which are the ones that hold the lens in place, it is to be

thought that the function of these ciliary muscles has to be oriented to do something in

the lens, so It is said that when these muscles, that is, the ciliary muscles, are

relaxed, the cornea is elongated. Why? because when this muscle is relaxed the

suspensory ligaments are, let's say, contracted, they are elongated and that causes the lens

to flatten and this helps it to lose its concavity a little and we can see distant objects,

now, when we want to focus on an object that is close where they have to

contract the ciliary muscle so that those suspensory ligaments of the lens relax and

the lens adopts its biconvex shape, this will allow us to focus on distant objects

and this is thanks to the parasympathetic, which is what gives us that reflex that is the famous accommodation reflex

, that is the important thing about those ciliary muscles, to finish this tunica media then

we are going to talk about the iris, the iris you know is the part of the eye that has the pigment,

it is the one that has the color that It gives the characteristic color to people,

that iris has an anterior face that sees towards the anterior chamber of the eye, that is, it sees towards what

is the cornea and it will have a posterior face that sees towards the face. The posterior part of,

sorry, is the one that sees towards the posterior chamber of the eye, it will have a larger circumference, which is where

it is, let's say, grabbed to be able to be suspended like this, and it will have an edge that is free,

which is the smaller circumference. So what do we find on the previous face? First we know

that the anterior face is the posterior limit of the anterior chamber, in the next video of the

eye that I will talk about the means of reflection I will also talk about these chambers so that you can

understand what I mean by anterior chamber and what I mean I with a posterior camera, then

you will see that the iris has a set of folds on its anterior surface that are called

radiating folds of the iris, this is a vision of the iris, look at all the folds that it has,

of course this is a vision little microscopic and notice that it has two rings,

an internal colored ring that is the smaller colored ring whose thickness is one to two

millimeters while it also has a larger colored ring that would be its largest

or external circumference that measures three to four millimeters thick, you already know that the larger red ring

is the one that is outside, so the smaller red ring now see on its

posterior face it is going to have two relations, in the central part it is related to the

anterior face of the lens we are talking about the posterior face of the iris and in the peripheral part it is

in relation to the ciliary processes, now its greatest circumference is the place where the iris

is inserted specifically at the level of what is the ciliary body, which remember that it is this area,

also in that The place where the angle between the iris and the cornea is formed, which is the famous

iridium corneal angle, is the place where the Schlemm duct is, which is the famous duct that absorbs

or reabsorbs, rather, the aqueous humor, now at the level of That corneal iridium angle there are a

series of fibers that make up my pectineal ligament, now its smaller circumference,

which is the one that is free, is what forms the pupillary orifice, the famous pupil that

is nothing more than the space that remains in the center of the iris through which light can penetrate towards what

is the eye, now, the iris has two sphincters, it has a muscle that is the most medial of the two,

which is the sphincter of the pupil muscle, if it is a sphincter it means closing the pupil,

remember that the parasympathetic does this process called miosis, while there is a

muscle that is a little more towards the periphery which is the opposite muscle to the one

I just told you would be the pupil dilator muscle, This pupil dilator muscle

was controlled by sympathetic impulses, which is why the sympathetic muscle causes dilation of the eye,

which is a process called mydriasis, which would be the opposite of miosis. We are going to go on

to describe what the inner tunic is, but first don't get away from the video

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the content of the channel, you can see the remaining ocular videos in addition to the three ocular videos

on my channel there is also the video of the orbit the oxea part, the contents of the walls of the

orbit and also the tear duct and the ocular muscles. This retina is going to divide

in three portions, a first portion that would be the most posterior, which is the retina itself,

remember that this internal tunic, also called the nervous tunic because it houses

nervous structures such as the retina, this retina despite the fact that books describe it. They draw

yellow, it really is transparent, it is colorless; This posterior part that would be the retina itself or

as they called it before because this is really an old name, retina itself of the part

that has the nervous function and the one that captures the light impulses transforms them into images

that are the ones that we can perceive, this is where the magic of vision occurs,

so it is the one that after the fiber gather passes through the cribriform plate that formed the

sclera and that helps form the choroid and it is that it forms the optic nerve, in fact It is said

that the retina is nothing more than an extension of the optic nerve, so it will go, let's say, from

that emergence to the optic nerve to the ora serrata, in the ora serrata it is nothing more than the

structure in which that retina is narrowed. From the ora serrata onwards, the position of

the retina changes and moves to its second portion, the first portion, which is the retina itself, reaches

the ora serrata; Its external face, which would be the one you see on the outside, is the one that is

in contact with the choroid but remember that it does not adhere to it while its internal face

is the one that is in contact with the vitro body, when we see the third video By eye in the

reflection media you will understand that it is the vitro body but basically this structure that you see

here that has a consistency more or less a form of glass that is why they call it vitreous, now,

in the center of the retina we are going to find what which is the optic papilla, which is the place

where the optic nerve emerges, eye, I am telling you in the center but we are going to see in

an image that they are not really in the center, this is a superior view of the left eye

and precisely the center of the eyeball would be this area that you see here depressed, right now

I am going to explain to you what it is, while then the emergence of the optic nerve, which is supposed to

be where the optic papilla is, is actually medial with respect to the central axis of the eye and

This structure, which if it coincides with the central axis of the eye, is called the macula lutea. We are going to see that

the optic papilla, which in this view looks perfect, see that the center, which is the macula lutea, measures

3 millimeters to 1.5 millimeters, while medial to It and slightly above it is the

optic papilla, which is where the optic nerve emerges, which measures 1.5-1.8 millimeters in diameter and that

is what we can see when we do an eye fundus. Now this optic papilla has a

central point that is called the central excavation, so see that it is from it that the

retinal blood vessels emerge, now I am going to explain to you what those blood vessels are like and in the macula

lutea, which would be this structure that is called that, it is called the macula lutea because it is a color

really yellowish, the first thing you have to know is that the blood vessels do not reach

it, which is why it is said to be avascular. In addition, it has a central excavation, which is what we saw

right now in the image, which looks like an excavation called central fovea and also in the

center of the central fovea there is another deeper depression which is the foveola, so what

are the retinal vessels? Notice, these are some branches of the central retinal artery,

they are divided into two groups of branches, some branches that go medially that are called nasal branches

since the nose is supposed to be here, and some branches that go to the lateral side that They are called

temporal branches because the temporal bone is supposed to be here, this is the nomenclature of

these arteries, notice then that the central retinal artery, the ascending

and descending branch, and then it is divided into nasal and temporal branches, which are the that we saw in the

previous image, then the ascending would give the superior nasal and the superior temporal and the

descending would give the inferior temporal and the inferior nasal. Now we end up with the first

portion of the retina, which is the most complicated, then we would have the second portion, which goes from

the ora serrata forward. It is all this that you are seeing that covers the

internal part of the entire ciliary body, that is why it is called the ciliary portion of the retina, really

the nervous function is very primitive here, the vision function is very scarce because it

is very rudimentary, the retina that is found at this level and in front of it when it reaches

the iris covers the even more rudimentary posterior part of the iris, which is a retina that is not

reactive at all and we call it the iris portion because it is posterior to the iris. So this

was the entire video, I hope you liked it and don't forget to subscribe to the little circle that appears

here and like the video if you liked it, I invite you to watch the next video carefully and look for the

videos on my channel too of ocular muscles and the lacrimal apparatus videos, thank you very much