Structure And Working Of Human Eye Pdf


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26.03.2021 at 04:15
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structure and working of human eye pdf

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Human Eye: Anatomy, parts and structure

Members of the animal kingdom use different strategies to detect light and focus it to form images. Human eyes are "camera-type eyes," which means they work like camera lenses focusing light onto film. The cornea and lens of the eye are analogous to the camera lens, while the retina of the eye is like the film. To understand how the eye sees, it helps to know the eye structures and functions:. The coating on the interior back of the eye is called the retina. When light strikes the retina, two types of cells are activated. Rods detect light and dark and help form images under dim conditions.

The day aims to focus attention worldwide on blindness and vision impairment. The Human eye works on the refraction of light through a natural convex lens made up of transparent living material and enables us to see things around us. And the ability to see is called vision, eyesight, or drishti. The human eye consists of the cornea, iris, pupil, ciliary muscles, eye lens, retina, and optical nerve. The front part of the eye called the cornea is made of a transparent substance and its outer surface is convex in shape. It is through the cornea that the light coming from objects enters the eyes. Just behind the cornea is the iris which is also called coloured diaphragm.

Human eye , in humans, specialized sense organ capable of receiving visual images, which are then carried to the brain. The eye is protected from mechanical injury by being enclosed in a socket, or orbit, which is made up of portions of several of the bones of the skull to form a four-sided pyramid, the apex of which points back into the head. Thus, the floor of the orbit is made up of parts of the maxilla, zygomatic, and palatine bones, while the roof is made up of the orbital plate of the frontal bone and, behind this, by the lesser wing of the sphenoid. The optic foramen , the opening through which the optic nerve runs back into the brain and the large ophthalmic artery enters the orbit, is at the nasal side of the apex; the superior orbital fissure is a larger hole through which pass large veins and nerves. These nerves may carry nonvisual sensory messages—e.

How your eyes work

The open eye features the pupil, the black centre, the iris, the coloured ring surrounding the pupil, and the sclera, the white of the eye. The caruncle is tucked into the inner corner of the eye, while the upper and lower eyelids lubricate and protect. Our vision allows us to be aware of our surroundings. Eighty per cent of everything we learn is through our sight. Your eye works in a similar way to a camera. When you look at an object, light reflected from the object enters the eyes through the pupil and is focused through the optical components within the eye. The front of the eye is made of the cornea, iris, pupil and lens, and focuses the image onto the retina.


The Structure of the Eye. • Gross Anatomy of the Eye. – Pupil: Opening where light enters the eye. – Sclera: White of the eye. – Iris: Gives color to eyes. – Cornea.


Structure and Function of the Eyes

Special cells called cones and rods are located in the retina. These cells are known as photoreceptors and help absorb light. The majority of the cones are located in the macula, or central area, of the retina. Cone cells help us see colour and detail.

FUNCTIONS OF THE EYE

The human eye has been called the most complex organ in our body. It is amazing that so small can have so many parts. Eye is a natural optical instrument.

Get special offers, reminders, information on contact lens care, and more - all based on YOUR vision care needs. Join EyeFile Already a Member? Log in now. Made of many working parts, the human eye functions much like a digital camera. Rods and cones convert the light from our retinas into electrical impulses, which are sent by the optic nerve to the brain , where an image is produced. The macula is the part of the retina that gives us central vision. Another function of the eye is to produce tears.


Components of the Eye 8 The Cornea and the Sclera 9 The Limbus and the Anterior Chamber 10 The Iris and the Pupil 11 The Ciliary Body​.


SAVE YOUR SIGHT

Eyes are organs of the visual system. They provide animals with vision , the ability to receive and process visual detail, as well as enabling several photo response functions that are independent of vision. Eyes detect light and convert it into electro-chemical impulses in neurons. In higher organisms, the eye is a complex optical system which collects light from the surrounding environment, regulates its intensity through a diaphragm , focuses it through an adjustable assembly of lenses to form an image , converts this image into a set of electrical signals, and transmits these signals to the brain through complex neural pathways that connect the eye via the optic nerve to the visual cortex and other areas of the brain. The most simple eyes, pit eyes, are eye-spots which may be set into a pit to reduce the angles of light that enters and affects the eye-spot, to allow the organism to deduce the angle of incoming light.

 Твое сокровище в беде, коммандер, - пробормотал .

Не спуская со Стратмора ледяного взгляда, Сьюзан сделала шаг вперед и протянула к нему руку с зажатым в ней предметом. Стратмор был почти уверен, что в руке Сьюзан сжимала беретту, нацеленную ему в живот, но пистолет лежал на полу, стиснутый в пальцах Хейла. Предмет, который она держала, был гораздо меньшего размера.

Хейл промолчал. - Рано или поздно, - продолжала она, - народ должен вверить кому-то свою судьбу. В нашей стране происходит много хорошего, но немало и плохого.

 Коммандер, не думаете же вы… - Сьюзан расхохоталась. Но Стратмор не дал ей договорить.

5 Comments

Josh W.
26.03.2021 at 09:15 - Reply

The structures and functions of the eyes are complex.

Brie C.
29.03.2021 at 16:47 - Reply

Question 1 What is night blindness?

Lucille A.
29.03.2021 at 23:29 - Reply

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Amitee S.
31.03.2021 at 23:21 - Reply

Three layers of human eye​​ Cornea further extends with a membranous structure called conjunctiva. The connecting area of cornea and conjunctiva is limbus. External fibrous coat is formed of cornea and sclera. This coat is formed by the iris, ciliary body and choroid (anterior to posterior).

Tilly S.
04.04.2021 at 11:26 - Reply

Each muscle coordinates with a muscle in the opposite eye. This allows for parallel movement of the eyes and thus the binocular vision characteristic of humans.

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