Structure Of Eye And Its Functions Pdf

structure of eye and its functions pdf

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The cornea is the transparent part of the eye that covers the front portion of the eye.

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Parts of the Eye. Here I will briefly describe various parts of the eye:. The sclera is the white of the eye. The Cornea. The cornea is the clear bulging surface in front of the eye. It is the main refractive surface of the eye. The graph on the right shows the optical density -log transmittance of the lens as a function of wavelength.

Basically, the role of the eye is to convert light into electrical signals called nerve impulses that the brain converts into images of our surroundings. Light rays pass through the pupil in the cornea. Aqueous humour — maintains the pressure in your eye and nourishes the cornea and the lens by supplying amino acids and glucose, as well as vitamin C. Choroid — a thin layer of blood vessels that nourish the retina and absorb scattered light. Ciliary muscles — a circular muscle that relaxes or tightens to enable the lens to change shape for focusing. Cornea — a clear covering on the front of your eye that focuses light entering the eye.

Anatomy of the Eye

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. Similarly, the macula allows us to read and clearly recognize people's facial details, such as eye colour and whether they have freckles. The majority of the rods are located in the peripheral, or outer area, of the retina. Rod cells allow us to see in poor lighting and give us our night vision.

There are six muscles that attach to the eye to move it. These muscles originate in the eye socket orbit and work to move the eye up, down, side to side, and rotate the eye. It moves the eye upward. It moves the eye downward. It moves the eye inward toward the nose. It moves the eye outward. It travels through a small pulley the trochlea in the orbit near the nose and then attaches to the top of the eye.


the orbit surrounding, which protect the eyeball, give it flexibility to function. The adnexal structures, like eyebrows, eyelashes, eyelids, protect.


Structure and Function of the Eyes

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.

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.

Structure and Function of the Human Eye

How your eye works (parts of the eye)

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.

The structures and functions of the eyes are complex. Each eye constantly adjusts the amount of light it lets in, focuses on objects near and far, and produces continuous images that are instantly transmitted to the brain. The orbit is the bony cavity that contains the eyeball, muscles, nerves, and blood vessels, as well as the structures that produce and drain tears. Each orbit is a pear-shaped structure that is formed by several bones.

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.

Пуля ударила в кафельную плитку азульехо чуть сзади. Осколки посыпались вниз и попали ему в шею. Беккер рванулся влево, в другую улочку.

Стол был завален компьютерными распечатками и выглядел каким-то чужеродным в этом задернутом шторами помещении. - Тяжелая неделя? - спросила. - Не тяжелей, чем обычно.  - Стратмор пожал плечами.  - Фонд электронных границ замучил неприкосновенностью частной жизни и переписки.

Eye anatomy and function

Мотоцикл каким-то чудом перевалил через гребень склона, и перед Беккером предстал центр города. Городские огни сияли, как звезды в ночном небе. Он направил мотоцикл через кустарник и, спрыгнув на нем с бордюрного камня, оказался на асфальте.

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Daila A.

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Iris: The iris is the colored part of the eye that regulates the amount of light entering the eye. Lens: The lens is a clear part of the eye behind the iris that helps to focus light, or an image, on the retina. Macula: The macula is the small, sensitive area of the retina that gives central vision.

Vail V.

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Eyes. Structure and Function. The eye transmits visual stimuli to the brain for interpretation and, in doing so, functions as the organ of vision. The eyeball.

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