The vascular membrane, which is responsible for the accommodation, adaptation and nutrition of the retina, is a very important part of the structure of the eyeball. It consists of several parts, one of which is the ciliary (ciliary) body. It consists of many vessels and cells, the structure of which is characteristic of smooth muscle tissues.
Such cells are arranged in layers, and each of them has its own direction. Thanks to this, the necessary functionality of the ciliary body is achieved, which consists in maintaining continuous nutrition of one's own muscle fibers and ensuring the ability of the eye to focus at different distances (accommodation). Another important function of the education in question is the stabilization and maintenance of the desired pressure inside the eyeball.
Eye Structure: Anatomy
So what is the named part of the choroid, and what are its functions? To understand, you need to consider the structure of the eye. Anatomy distinguishes 4 main components in the visual organ:
- The peripheral part, also called the perceptive (it directly includes the eyeball, the protective organs of the eye, the adnexa and the muscular apparatus responsible for the movement of the eyeball).
- Pathways consisting of the optic nerve, intersection and tract.
- Visual centers in the subcortex.
- Higher visual centers that are located in the back of the cerebral cortex.
The eyeball is a very complex optical device, which is confirmed by the eye diagram below.
The main task of this organ is to transmit the correct image to the optic nerve. And all the components of the eyeball are involved:
- cornea;
- anterior chamber of the eye;
- iris;
- pupil;
- the lens;
- vitreous body ;
- retina;
- sclera;
- choroid (in fact, the ciliary body of the eye is part of it).
It is, as the scheme shows, between the sclera, iris and retina.
Ciliary body: structure and functions
From the point of view of anatomy, the described part of the eyeball is a closed ring-shaped figure behind the iris, under the scleral membrane of the eye. Such an arrangement, by the way, does not allow a direct examination of the ciliary body.
Considering the structural structure of this formation, we can distinguish two of its components: ciliary and flat.
- The first comes close to the serrated edge, and its width fluctuates around 4 mm.
- The second, ciliary, reaches a width of up to 2 mm. It is on it that special processes (ciliary or ciliary) are located, which together represent the ciliary corona. They are directly involved in the formation of fluid inside the eye. This happens due to the filtration of blood in many blood vessels, which literally penetrate each of the processes, which, incidentally, have a lamellar shape.
Examining the ciliary body at the cell level, you can see that it consists of two layers: mesoderm and neuroectoderm. The first consists of two types of tissue - connective and muscle. But neuroectoderm is limited by the presence of only epithelial cells, the presence of which is due to the spread of the latter from the retinal layer.
It turns out a kind of layer cake, the layers in which are arranged as follows (from the deepest):
- muscle layer;
- vascular layer;
- basement membrane;
- pigment epithelium;
- epithelium without a pigment layer;
- inner separation membrane.
Next, we will consider in detail the main components of the ciliary body, which includes the eye scheme.
Muscle layer
This layer is characterized by the presence of several muscles running in different directions: longitudinal, radial and circular. Muscular fibers called the Brucke muscles, which are the outer part of the layer, are distinguished by a longitudinal orientation. Under them are the radially directed muscles of Ivanov. And the closing ones are the circularly directed muscles of Mueller.
The main task of each layer is to participate in the process of ensuring the ability of the eye to clear vision at different distances (accommodation). It happens as follows. The inner part of the ciliary body is connected with the outer part of the lens (its capsule) through the ciliary belt, consisting of a large number of the finest fibers. The objective of this education is to fix the lens in the right position, as well as to assist the ciliary muscle during accommodation processes.
Fibers of the ciliary girdle, also called zonal, are divided into two types: front and rear. The former are attached to the equatorial and anterior regions of the lens capsule, and the latter are attached to the equatorial and, accordingly, posterior. Thanks to them, the tension and relaxation of the ciliary muscle is transmitted to the lens membrane, and it becomes either more rounded or more elongated, which is the process of focusing the eye at a certain distance.
Vascular layer
The structure of this layer is not much different from the structure of the choroid of the eye, a continuation of which it is. The composition of the vascular layer includes for the most part veins of various sizes. This is due to the fact that most of the arteries of the eye are located next to the choroid and, oddly enough, in the ciliary body, but in its muscle part. It is from there that the small arterial vessels enter the choroid.
Basement membrane
A continuation of the choroid of the eye is this layer. From the inside, it is covered with two types of epithelial cells: pigmented and pigmentless. These types of cells are nothing more than the non-functioning part of the retina. Behind them is a border membrane, which is not only the final layer of the ciliary body, but also separates it from the vitreous.
The physiological role of the ciliary body
There are several main functions of the ciliary body:
- Participation in the accommodation processes, due to the ability to change the shape of the lens capsule using the muscle layer of the ciliary body. Through accommodation, precise tuning within 5 diopters is ensured.
- Providing a sufficient amount of intraocular fluid, due to the fact that the ciliary body contains a large number of blood vessels and, as a result, has good blood supply. Subsequently, through this fluid, the pressure necessary at a certain moment on other components of the eyeball is exerted.
- Maintaining proper pressure inside the eye, which is one of the conditions for providing a clear and clear vision.
- The vascular system involved in the nutrition of the ciliary body also nourishes the retina.
- The ciliary body acts as a support for the iris of the eye.
Pathologies of the ciliary body
In medicine, the diseases to which the ciliary body is exposed are distinguished:
- Glaucoma. With this ailment, the balance between the synthesized intraocular fluid and its outflow is disturbed.
- Iridocyclitis. It is characterized by the appearance of inflammatory processes in the ciliary body.
- Reduced pressure inside the eye, due to a decrease in the volume of fluid in it. This can lead to swelling of the layers of the epithelium.
- Neoplasms in the ciliary body. In some cases, they may be poor quality.
- Various pathologies of a congenital nature.
When the first signs of the problem appear, it is necessary to undergo a special examination to see the ciliary body of the eye, find out what pathological processes begin in it, and if necessary, prescribe treatment.
Total
Summing up, it should be said once again that the ciliary body, being a component of the choroid of the eye, is responsible for a number of important functions inside the eyeball. Among them are normalization of pressure inside the eye and maintaining its balance, synthesis of intraocular fluid, ensuring normal blood circulation in nearby tissues, and, of course, participation in the accommodation process. It should be remembered that diseases of the ciliary body will be reflected in the general state of human vision.