🥇 Anatomía del OJO 1/3 - Generalidades y Túnica Externa
Summary
TLDREste video educativo, dirigido por Juan José Sánchez, explora la anatomía del ojo en una serie de tres videos. En el primer video, se aborda la túnica externa del ojo, también conocida como túnica fibrosa, compuesta por la córnea y el esclerótica. Se destaca la importancia de la unión entre la córnea y el esclerótica, así como la función del ángulo iridocorneal en la reabsorción del humor acuoso. Además, se mencionan las estructuras externas como los músculos extraoculares y el aparato lagrimal. El video también cubre la topografía ocular, incluyendo los polos del ojo, el ecuador y los meridianos. El esclerótica se describe como una parte variando en grosor, con una porción cribosa donde el nervio óptico perfora. Finalmente, se destaca el ducto de Schlemm, crucial para el drenaje del humor acuoso y su implicación en la patología de la glaucoma. Este resumen ofrece un vistazo general y atractivo al contenido del video, despertando el interés de los espectadores.
Takeaways
- 📚 El video es una serie de tres partes sobre la anatomía del ojo, presentado por Juan José Sánchez.
- 👁️ La primera capa del ojo se llama túnica externa o túnica fibrosa, compuesta por la esclerótica y la córnea.
- 👁️🌐 La túnica media o vascular, incluye la coroides, el cuerpo ciliar y la iris.
- 👁️💡 La túnica interna o nerviosa está formada principalmente por la retina.
- 🔍 El ojo es un órgano circular, no tan pesado, con un peso de 7 a 7.5 gramos aproximadamente.
- 📏 Los diámetros del ojo son: anteroposterior de 2.5 cm, transversal de 23 a 24 mm y vertical de aproximadamente 23 mm.
- 🔭 El ojo no es una esfera perfecta; tiene una forma esférica con cinco sextantes en la parte posterior y un sexto en la parte anterior.
- 🏙️ El polo anterior del ojo es la córnea y el polo posterior es la esclerótica.
- 🌗 El ecuador del ojo es el diámetro que lo divide en dos mitades equidistantes del polo anterior al polo posterior.
- 📐 El méridiano es una corte que toca el polo anterior y el polo posterior del ojo.
- 🩸 La córnea es un tejido vascular y es el órgano que extiende el ojo hacia adelante, formando la sexta parte anterior.
- 🤍 La esclerótica, conocida como el blanco del ojo, tiene una espesor variable y su parte más gruesa está en la región posterior.
Q & A
¿Cuál es la estructura compuesta por la córnea y la esclerótica que forma la parte externa del globo ocular?
-La estructura compuesta por la córnea y la esclerótica se conoce como la túnica externa o túnica fibrosa, y forma la parte externa del globo ocular.
¿Cómo se llama la parte más posterior de la túnica externa del globo ocular?
-La parte más posterior de la túnica externa es la esclerótica, que también es conocida como el blanco del ojo.
¿Cuál es la medida aproximada del diámetro antroposterior del globo ocular en milímetros?
-El diámetro antroposterior del globo ocular mide aproximadamente 25 milímetros.
¿Qué es el ángulo iridocorneal y por qué es importante?
-El ángulo iridocorneal es la unión entre la iris y la córnea. Es importante porque es el lugar donde el humor ácido se reabsorbe en el ojo.
¿Cómo se llama la membrana que cubre la superficie anterior de la córnea y el párpado?
-La membrana que cubre la superficie anterior de la córnea y el párpado se llama conjuntiva.
¿Qué es la estructura que se encuentra en la unión entre la esclerótica y la córnea y que es importante para la transición de estas dos partes?
-La estructura que se encuentra en la unión entre la esclerótica y la córnea es el límbito esclerecorneal.
¿Cómo varía el grosor de la esclerótica en diferentes partes del globo ocular?
-El grosor de la esclerótica varía según su ubicación; es aproximadamente de 1 milímetro en la parte anterior, disminuye a 0.4 milímetros en la parte media y es más gruesa en la parte posterior con un grosor promedio de 0.6 milímetros.
¿Qué es el espacio episcleral y qué contiene?
-El espacio episcleral es una capa que se encuentra sobre la esclerótica. Contiene un tejido fibroso bastante laxo conocido como el tejido episcleral, y encima de este se encuentra la aponeurosis bulbar.
¿Qué son los músculos extraoculares y cómo se relacionan con la aponeurosis bulbar?
-Los músculos extraoculares son los músculos que mueven el globo ocular. Estos músculos penetran la aponeurosis bulbar, cruzan el tejido episcleral y el espacio episcleral para alcanzar y fijar la esclerótica del ojo.
¿Qué es la placa cribosa de la esclerótica y cómo se relaciona con el nervio óptico?
-La placa cribosa de la esclerótica es una área donde el nervio óptico perfora la esclerótica, dejando una serie de agujeros que le dan una apariencia de c筛jo. Este área es importante porque permite el paso del nervio óptico, que es el segundo nervio craneal, sin dejar un agujero completo.
¿Qué es el ducto de Schlemm y dónde se encuentra?
-El ducto de Schlemm, también conocido como seno venoso esclerocorenal, se encuentra en el ángulo iridocorneal entre la iris y la córnea. Es el lugar donde el humor ácido se reabsorbe después de ser producido.
¿Qué es la glaucoma y cómo está relacionado con el ducto de Schlemm?
-La glaucoma es una patología caracterizada por un aumento de la presión intraocular. Uno de los motivos por los que esto puede suceder es el obstáculo en los ductos de Schlemm, lo que impide la reabsorción del humor ácido y, por lo tanto, aumenta la presión dentro del ojo.
Outlines
📚 Introducción a la Anatomía del Ojo
Este primer párrafo presenta un video sobre la anatomía del ojo por Juan José Sánchez. Se anuncia una serie de tres videos que abarcarán la tunica externa, interna y medios de refracción del ojo. Además, se mencionan dos videos adicionales sobre los músculos extraoculares y el aparato lagrimal. Se proporciona una visión general de las capas del globo ocular, incluyendo la tunica fibrosa (sclera y córnea), la tunica media (córax, cuerpo ciliar y iris) y la tunica interna (retina). Se describe la posición del ojo en el hueso órbita y sus dimensiones, destacando que no es una esfera perfecta sino una forma esférica aproximadamente. Finalmente, se introduce la topografía ocular con términos como polo anterior, polo posterior, ecuador y hemisferios.
👁️ Anatomía de la Cornea y Tunica Fibrosa
El segundo párrafo se enfoca en la tunica fibrosa, compuesta por la córnea y la esclera. La córnea es una estructura transparente y avascular en la parte anterior del ojo que permite la luz a travesar. Se describe su forma hemisférica y sus dimensiones, además de su transición con la esclera en el límite esclerocorneal. Se menciona la importancia del ángulo iridocorneal, donde se reabsorbe el humor acuoso. Se explora la microanatomía de la córnea, incluyendo su epithelio anterior, lámina basal, sustancia propia y lámina posterior (Descemet's membrane). La esclera es conocida como el 'blanco del ojo' y su grosor varía según su ubicación, siendo más gruesa en la parte posterior donde el nervio óptico la perfora, creando una placa cribosa.
💡 Función del Ducto de Schlemm y la Tunica Fibrosa
Este párrafo profundiza en la estructura y la función del ducto de Schlemm, ubicado en el ángulo iridocorneal y responsable de la reabsorción del humor acuoso. Se destaca la importancia de este ducto para el mantenimiento de la presión intraocular, y se menciona la patología del glaucoma, que puede estar relacionada con la obstrucción de estos ductos. Se describe la relación anatómica entre la conjuntiva, el epitelio y la tunica fibrosa, así como la inserción de los músculos extraoculares a través del aponeurosis bulbar y la tunica escleral. Se concluye el análisis de la tunica fibrosa y se invita al espectador a suscribirse y seguir el canal para recibir más contenido relacionado.
📢 Conclusión y Llamado a Acción
El cuarto y último párrafo actúa como una conclusión y llamado a la acción para los espectadores. Se pide a los espectadores que no dejen de ver el video, les invita a suscribirse al canal, dar like al video y seguir los siguientes videos. También se ofrece la posibilidad de seguir al creador en Instagram. Se agradece la atención de los espectadores y se cierra el video con un mensaje de contacto y seguimiento.
Mindmap
Keywords
💡Anatomía del ojo
💡Tunica externa
💡Córnea
💡Esclera
💡Tunica media
💡Tunica interna
💡Retina
💡Músculos extraoculares
💡Aparato lagrimal
💡Humor acuoso
💡Glaucoma
Highlights
Se dividirá el estudio de la anatomía del ojo en tres videos: generalidades de la túnica externa, túnica interna y medios de refracción.
Existen dos videos adicionales sobre los músculos extraoculares y el aparato lagrimal.
La túnica externa del ojo, también conocida como túnica fibrosa, está compuesta por la esclerótica y la córnea.
La túnica media o vascular, incluye la coroides, el cuerpo ciliar y la iris.
La túnica interna, o túnica nerviosa, está formada principalmente por la retina.
El ojo es un órgano relativamente circular, pesando aproximadamente 7 a 7.5 gramos.
Los diámetros del ojo son anteroposterior (2.5 cm), transversal (23-24 mm) y vertical (aproximadamente 23 mm).
El ojo no es una esfera perfecta, sino que tiene una forma esférica con algunas variaciones en sus diámetros.
La distancia entre el centro del ojo, representado por el orificio pupilar, es de 6 a 7 cm en un sujeto adulto.
El ojo tiene dos polos: el polo anterior representado por la córnea y el polo posterior por la esclerótica.
El ecuador del ojo es el diámetro que lo divide en dos mitades equidistantes del polo anterior y posterior.
Los meridianos son cortes que pasan por el polo anterior y el polo posterior del ojo.
La córnea es una lámina anterior del ojo, forma la primera sexta parte del mismo y es esférica.
La córnea no es un tejido vascular y es fácil de transplantar.
El límite entre la córnea y la esclerótica se conoce como el limbo escleral.
El ángulo iridocorneal es crucial ya que es donde se reabsorbe el humor acuoso.
La esclerótica, conocida como el blanco del ojo, forma la parte posterior de la túnica fibrosa.
La espesura de la esclerótica varía según su localización, siendo más delgada en la parte media y más gruesa en la parte posterior.
El nervio óptico perfora la esclerótica por la placa cribriforme, que tiene fibras en forma de siete.
El conducto de Schlemm, también conocido como seno venoso escleral, está ubicado en el ángulo iridocorneal y es esencial para la reabsorción del humor acuoso.
Transcripts
Hi my loves! I hope you are feeling very well, welcome to a new anatomical video of
easy anatomy by Juan José Sánchez and today we will talk about the anatomy of the eye, we
are going to divide this organ, the eyeball, into three videos: in the first video we will talk about the
generalities of the outer tunic, which is this, in the second video we will talk about the inner tunic
, in the third video we will talk about the means of refraction. Apart from that, I created two
more videos that are not part of the eyeball but of the external structures as they are:
a video of extra ocular muscles that are the muscles that move the eyeball and a fifth
video that would be the lacrimal apparatus video, but the eyeball itself is going to be just three videos
. So we're going to start quickly by giving an outline of what the layers of the eyeball are
, we're going to talk about three layer groups or three layers of the eyeball. We will call the first layer
the outer tunic, in many books we get it with the name fibrous tunic,
it is composed of two parts, a more posterior one that would be the white of the eye which is the sclera
and a more anterior one that would be the cornea, the two of them are It then forms the outermost part
of the eyeball or the fibrous tunic. Then we have a tunica media that we also call
the vascular tunica, this tunica media is composed of three parts: a more posterior part called
the choroid or the choroid, a middle part called the ciliary body and a more anterior and central part
called the iris, this would be the tunica media. or vascular tunic and finally we would have the internal tunic,
also called nervous tunic, which is made up of a large structure that is the retina. So
this is more or less the configuration of the eye cut more or less in a horizontal plane,
as I explained in the first video it will consist of first talking about the generalities of the eye,
then the external tunic in the second video of the eyeball we will talk about the tunic media,
the internal tunic and in the third video of the structures that are here that are not part of
the tunic, which would be the chambers, the aqueous humor, vitreous body, those means of ocular refraction
of the lens itself. So let's start first by talking about the generalities of the eye, then the
eyeball, this would be a superior vision, this would be a lateral vision, it is housed within the
bone orbit, also on my channel a few months ago I uploaded a video of the bone orbit, what are the
bones that make it up, what are its limits, its components, you can find it and you have to
see it even before this so that you can understand the positioning of the eye well. So
it is a relatively circular organ, not so heavy, weighing 7 to 7.5 grams each, its
anteroposterior diameter is a diameter longer than the transverse diameter because it measures 2.5 centimeters,
that is, 25 millimeters, its transverse diameter, which is more shorter than the previous one, as I told you,
it more or less measures between 23 and 24 centimeters on average, 23 to 25 millimeters, no 23 centimeters,
23 to 24 millimeters on average, 23 to 25 millimeters, imagine centimeters would be very big. Now its
vertical diameter, which would be its smallest diameter, approximately 23 millimeters, notice that it
is not a perfect sphere but rather there is no agreement in any of its diameters, but
more or less it is a sphere shape, in fact it is said to have five posterior parts of a
large sphere and its first anterior sixth part is another sphere within the sphere, to make it
easier for you. So the distance in a normal live adult subject between the central part of the eye
represented by what you see there black, which would be the pupillary hole, is 6 to 7 centimeters
in the normal distance that one eye should measure from another, now let's go To talk about the ocular topography
itself, the eye, which some authors consider to be nothing more than the extension of the
central nervous system, will have two poles or points: an anterior pole represented by the most anterior part
of the eye, which is the cornea, central point of the cornea and a posterior pole that would be the most
central and posterior part of the sclera, ok in that they would be the two poles of the eye. Then we would have what
the equator is. What is the equator? The equator is a diameter that cuts the eye into two halves,
in an anterior half and a posterior half so that it will be equidistant at the same
distance from the anterior pole and the posterior pole and will always be represented then in
a frontal plane. Remember that we are seeing the eye in a superior vision, then we would have
the hemispheres, the hemispheres are the halves that remain in relation to the equator, the one that remains
in front of the equator would be the anterior hemisphere and the one that remains behind the equator
It would be the posterior hemisphere, a very important term is the meridian term. What is
the meridian? It is a meridional cut, the meridian is that cut that goes in the direction that touches the
anterior pole and the posterior pole, that is, I am going to cut the eye into two halves. What is happening?
The meridian is not that the cut is going to pass through the middle, no, the meridian I can make the cut
thousands of cuts in the eye as long as it touches the anterior pole and everything that the posterior pole,
now two meridians that are opposite like you You see this one as you can see here, it is going to divide the
eye into two halves so the meridian or the meridional cut can be a vertical cut,
it can be an oblique cut or it can even be a vertical cut, there are many cuts that I can
make to the eye . Be careful that it always touches the anterior pole and that it always touches the posterior pole. Now
we are going to move on to the anatomy of the eye itself, but first don't let go of the video and continue
[Music].
I invite you to subscribe here in the lower right corner, click [Music]
and don't forget to like the video. So it is very important that you subscribe to the channel here in
the lower right corner, you click on it and you are automatically subscribed to the channel. That is
the only thing I ask of you and in exchange you can access all of its content. So I remind you that
the outer tunic was made up, also called the fibrous tunic, by two structures,
previously this crystallite called the cornea and later by what is the sclera. We are going
to begin to describe the anatomy of the cornea first, then the cornea is an anterior lens,
it is what extends the eye anteriorly, it is what makes the anteroposterior diameter
longer than the transverse diameter, it is more or less a hemisphere that forms the first
anterior sixth part of the eye, what I told you at the beginning. While the
posterior fifths form in the sclera, then this cornea, the first thing you have to know is that it
is a vascular tissue, that is why it is so easy to transplant a cornea, well,
easy, so to speak, which is not It's so complicated to get the donor, I mean,
she's going to be in contact with two structures. According to the circumstances, it can be in
contact with the atmosphere directly, protecting the internal contents of the eye,
but also when we have our eyelids closed it is in contact
with the posterior surface of the upper eyelid, so it is transversely a little wider,
measuring 12 millimeters. while vertically it measures approximately 11 millimeters, so
it is not a perfect cylinder or a perfect circle but rather it is longer transversely,
now in thickness the center is much less thick the center measures 0.5 to 0.8 millimeters while that
peripherally, this is a cross section of the eye a superior view of it in fact
it is a little wider it measures about a centimeter, sorry, a millimeter wide on
the periphery near where the cornea then joins the sclera. Now, there is the union
between the cornea and the sclera, which we are going to call externally the sclerocorneal limbus,
in that same place we can see that the conjunctiva, which is a layer of tissue that covers
the anterior surface of the cornea along with the eyelid It has a protective membrane, this conjunctiva
will also be attached to what is the cornea and what is the sclera, an area called
sclerocorneal limbus, this is the place where you see, see that the sclera communicates with the cornea,
something important It is the beveling in the oblique cut that the cornea has at the expense of its
most anterior face, this explains why then it is said that the sclera
initially covers what is the anterior face of the cornea, because you see that since it is beveled,
The fact that it is not a completely straight cut means that the sclera is just placed anteriorly
in front of what the cut is. Now in this same union between what is the sclera and the
cornea is the sclerocorneal union, limbus in the anterior part itself all this is called is union,
we are going to find a structure called trabecular reticulum which is a network of fibers that can be seen
much better when it is a histological view, a microscopic view. Now there is an angle between
the iris and the cornea, this angle is called the iridocorneal angle, the iridocorneal angle, and the corneal angle
of the cornea. This angle is very important because this is the place where the
aqueous humor is reabsorbed. Let's see a little bit now. closer so that you understand how the magic happens
at the level of that iridocorneal angle. Now in this histological section, to locate them this would be the
sclera, this would be the cornea, this the iris and this the lens, we are going to talk now
about the layers that the cornea has, a more anterior layer which is the so-called anterior epithelium,
then It has a posterior limiting membrane or posterior limiting lamina, no, anterior sorry,
which would be the basal lamina of that epithelium, this anterior limiting membrane is also called the
anterior elastic membrane, then it has what is the substance itself, behind the substance itself
we find the posterior limiting membrane, which is also called Descemet's membrane,
this limiting membrane is posterior, which would be the posterior basal membrane, and behind it the
posterior epithelium, which in many books is called mesothelium, but if you already have
histological knowledge, it will know that the mesothelium is nothing more than a flat epithelium, that
is, it is a type of epithelium that is the one that will then be in contact with what we call
the anterior chamber of the eye, perhaps they do not yet know what the anterior chamber is That is what we are going
to touch on in the middle of refraction, which is the third video of the eyeball. Let us then quickly move on
to the sclera, which is what we colloquially know as the white of the eye,
that is, it is the part that forms the external fibrous tunic together with the cornea, but which is
posterior and forms the posterior fifth-sixth parts. of the eyeball, this sclera
varies in thickness according to its location, anteriorly it measures approximately 1 millimeter
thick, in the middle part it narrows quite a bit, it measures 0.4 and in the posterior part, I
said it the other way around, in the posterior part it is the thickest The one of a millimeter is the average of 0.4
and the previous one is the one that is 0.6. Then the thicker posterior narrows in the middle region
and becomes slightly thicker than the anterior, but never as thick as in the posterior part.
Now the radius that I drew here as if it were a diameter of approximately 11 to 12
millimeters, that is, from the center of the periphery, when one of the two radii forms this
diameter, which would be the transverse diameter of the eye, which is between approximately 23 and 24 centimeters.
So you know that I drew the diameter here but I was really referring to the center of the periphery,
which is the radius of 11 to 12 millimeters. Now superficially to what the sclera is,
which would be what you see here in white, there is a space that is the episcleral space, above that
episcleral space there is a fibrous tissue, a fairly loose tissue that is the episcleral tissue,
outside the episcleral tissue we find the bulbar aponeurosis. So the sclera order, which
is the sclera, episcleral tissue and then the bulbar aponeurosis, it is important to know that this
aponeurosis is penetrated by the muscles of the eye, which are the extra ocular muscles that we are going to see
in the video that I told you later, This muscle, these extra ocular muscles are inserted at the level
of the sclera, therefore they have to pierce the bulbar aponeurosis and have to
cross the epithelial tissue with the episcleral space in order to reach
the sclera of the eye. . Now in the posterior part, which is the thickest part of the
sclera where the retina converges and forms the optic nerve, this optic nerve pierces the
sclera but the sclera does not leave a complete hole for the optic nerve to pass through.
No, it leaves cribriform fibers, many holes that look like a sieve, that is why this area
that I have here is called the cribriform plate of the sclera. It should be noted that this optic nerve,
which would be the second cranial nerve, is surrounded by a membrane that It is the membrane of the optic nerve
and this membrane is continuous with the fibers of the sclera so that they form a single unit.
Now this is a quite microscopic, histological section here we can see what the cornea is,
the sclera, this would be the sclerocorneal limbus, we are going to see the scleral venous sinus, this
scleral venous sinus is also known as Schlemm's duct, see what it is located in the
iridocorneal angle which is between the iris that I told you a while ago and the cornea, here that
schlemm duct is what reacts to the aqueous humor once it is produced, in the third
refraction medium video that I will tell you about the aqueous humor. I will explain well what the circulation is like,
who makes it up and how they react here. What I want you to know is that at that level of the
sinus venosus that the Schlemm duct itself is where the aqueous humor is reabsorbed. So it is
very important to know this anatomical point since there is a pathology called glaucoma, which is an increase
in intraocular pressure that occurs for many reasons but one of them is that there is obstruction of
these Schlemm ducts so that the aqueous humor cannot be reabsorb and therefore increases
the pressure inside the eye. This is a superior transverse view with this we finish
the video of the external tunic, forward the cornea as it is in contact with what is
the conjunctiva which is this membrane that you see here, this would be the eyelid and see how it continues with
the sclera, this would be the bulbar aponeurosis, this tissue that is seen there would be the episcleral
and this would be the sclera, see how it continues with the lamina, not, let's say with the cover
that the optic nerve has, here this iridocorneal angle level is then assumed Which is where
the Schlemm duct is, which is what absorbs the aqueous humor. This was then the first
eyeball video, don't forget to subscribe again, I ask you here in the little circle that appears here,
if you liked the video, like it and watch the following videos, you can also follow me
on Instagram at @juan_sanchez1315. Thank you for your attention
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