Can u plz explain all the parts n functions of our eyes???
An eye has several different parts that act together to provide us vision.
- Cornea: it is the outermost, white, transparent, dome shaped window of eye. It focuses the light that enters inside the eye.
- Sclera: It is the whitish layer of eye that is connected to the cornea. This layer provides protection and helps the eye to move by providing extra cellular muscles.
- Retina: It is the innermost layer of the eye. It contains nerve tissues which send the impulse to the brain through optic nerve. The images that we can see are formed in retina. It contains two types of light sensitive cells – rod and cone.
- Pupil: Pupil is the hole at the centre of eye. The pupil may get smaller or bigger depending upon the light intensity.
- Iris: It is the colored part of eye. Iris gives the colours of our eye due to the presence of pigments. It is made up of connective tissues and smooth muscles. Its role is to relax and contract pupil to control the entrance of light inside retina.
- Lens: Lens is the transparent part located just immediately behind the iris. It focuses the light and passes towards retina.
- Optic nerve:it connects the eye with brain. The axons of the nerve tissues of retina get bunched together to form the optic nerve.
We enjoy the world and all the things around us because we can see it through our eyes. It is through the different parts of the eyes wherein we get to see the real beauty of the world and how amazing each part functions. We have different parts of the eyes, and these parts include anterior and posterior chambers, pupil, iris, lens, retina, vitreous humor, fovea, sclera, cornea, and macula. Each of these parts has very important functions in our eyes so that we will be able to have a good vision which we must know in order for us to protect our eyes from things that can be harmful.
The parts of the eyes that are usually common to us and which we always hear are the cornea, retina, pupil, iris and lens. The cornea can be seen in the outer portion of the eyes which is transparent, clear and bulging. Light passes by the eyes through the cornea. The retina is found at the back of the lens and it serves as the screen wherein the images are actually formed. Made up of very sensitive cells, this retina and its cells are directly connected to the optic nerves. The whole at the center of the iris is the pupil. This is where the light passes through to the lens.
The iris, one of the parts of the eyes, can be found at the back of the cornea wherein it directs the constriction and the dilation of the pupil. The one which helps in the formation of the image in the retina is a transparent, elastic as well as convex part named the lens. Some parts of the eyes wherein people are not so aware of are the anterior and posterior chambers, sclera, vitreous humor, fovea and macula. The white portion of our eyes which is behind the cornea is the sclera. Its main function is to protect the inner portion of the eyes. On the other hand is the vitreous humor which is a transparent jelly-like space between the lens and the retina.
The anterior and posterior chambers are also other parts of the eyes. The portion between the cornea and the iris is the anterior chamber. The posterior chamber is the portion between the iris and the lens. The central fixation or the central of visual field is the when the retinal locus focuses on something. A thing, tightly packed and elongated fovea is also composed of cones with no rods making it a location for the color vision. The pigment covering the fovea is the macula. It serves a filter that absorbs blue and ultraviolet radiation.
Our eyes do amazing things. It is through the different parts of the eyes that we can see the beautiful things that surround us every day of our lives. Do you ever wonder why we can see things like this? We have different parts of the eyes, and these parts include anterior and posterior chambers, pupil, iris, lens, retina, vitreous humor, fovea, sclera, cornea, and macula. Each part plays a unique role and they all work together in order for our eyes to see. It is important to know each of the functions so that we know how to protect our eyes from things that can be harmful.
The common parts of the eyes to most people are the cornea, pupil, retina, iris and lens. These parts are always heard most of the time. The cornea can be seen in the outer portion of the eyes which is transparent, clear and bulging. Light passes by the eyes through the cornea. The retina is found at the back of the lens and it serves as the screen wherein the images are actually formed. The retina is made up of very sensitive cells which are directly connected to the optic nerves. The whole at the center of the iris is the pupil. This is where the light passes through to the lens.
Aqueous Humour: Between the iris and the cornea is a space filled with a watery fluid called the aqueous humour. This has a refractive index of 1.337. The aqueous humour baths both the cornea and the lens. It is constantly replenished by the ciliary body. It drains from the eye through the canal of schlem.
Choroid: The choroid lies between the sclera and the retina it provides the blood supply to the eye. The blood supply gives nutrition to the various parts of the eye, just like any other portion of the body.
Ciliary body: Just in front of, and continuous with, the choroid is the ciliary body. This is a muscular tissue in the form of a ring, and is roughly triangular in cross-section. The ciliary body has ligaments attached to it. The ligaments are attached to the crystalline lens. The ciliary body controls the tension on these ligaments which in turn alters the power of the lens. The ciliary body also produces aqueous humour.
Cornea: The front portion of the sclera has a section that is transparent. This transparent window known as thecornea is attached to the sclera and is the major refractive power of the eye. In other words it is the part of the eye that provides most of its focussing power.
Fovea: The center of the macula; gives the sharpest vision. When we fixate or look directly at an object it is imaged on the fovea.
Iris: The iris is in front of the ciliary body. The iris is a muscular and pigmented tissue forming a circular curtain with a hole in the centre. The hole in the centre of the iris is called the pupil. The iris controls the amount of light which enters the eye by changing the pupil's diameter.
Macula: The small sensitive area of the retina that gives central vision; contains the fovea.
Optic Nerve: The optic nerve connects the retina to the lateral geniculate nucleus, which is in the middle of the brain. This is the first connection made by the visual system in the brain.
Retina: The retina is made up of transparent, sensory and nervous tissue carrying blood vessels, nerve cells and nerve fibres. At the back of the retina, the nerve fibres all come together and emerge as the optic nerve. The retina lies very close to the choroid (middle coat) but is attached to it only at the optic nerve and the ora serrata (where the retina ends and the ciliary body begins).
The nerve endings on the inside of the wall of the retina terminate in light-sensitive cells of two types ñ rods and cones. Rods are used for peripheral vision and night vision. Cones require bright light and provide fine detail and colour vision. The point on the retina where the nerve fibres leave to form the optic nerve is called the optic disc or blind spot.
Sclera: The outside covering of the eye is a protective envelope of leathery connective tissue known as the sclera. This is the white coating on the outside of the eyeball, commonly known as the white of the eye. It completely envelops the globe except at the front of the eye and maintains the shape of the globe. It also provides a firm anchorage for the extra ocular muscles that control the eye's movement.
The crystalline lens has several functions:
Transparency--to provide a clear medium through which light rays from an object can reach the retina.
Optical--to focus a sharp image of an object on the retina.
Accommodation--to vary its refractive power, thus providing clear images of objects over a wide range of distances. The dynamic accommodation process maintains a sharp retinal image via a continuous feedback mechanism. Loss of the accommodative function, presbyopia, is considered ``normal'' or ``natural'' in the fifth decade.
Anatomic--to create a functional barrier between the anterior and posterior segments of the eye.