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Your Eyes (for Kids) - KidsHealth

Other neurons in the neural retina process some of the information about what we see and send it to the optic nerve. The optic nerve then sends this information to the brain to finish processing. The lens is a transparent disc-shaped structure in the inner part of the eye. It lies directly behind the cornea and iris. The lens changes its shape to allow the eye to focus on near or far objects. Light rays pass through the lens and are focused on the retina to create images of objects at different distances from the body. The accessory adnexal parts of the eye include the eyelids, conjunctiva and lacrimal tear glands.

They protect, lubricate and support the eyeball. The eyelid is a fold of skin that covers and protects the eye. Muscles around the eye raise and close the eyelid. The eyelid has sebaceous glands that make an oily secretion that prevents the watery film on the eye from evaporating and the eyelid from sticking together.

The eyeball

The eyelid works like a windshield wiper that helps to lubricate the eye and keep the surface of the eye free of dust and other debris. The eyelashes grow from the edges of the eyelid. They also help protect the eye from dust and debris. The conjunctiva is a clear mucous membrane that covers the inner surface of the eyelid and the outer surface of the eye.

The conjunctiva secretes a watery fluid mucus that helps lubricate the eyeball and keep it moist. The lacrimal gland also called the tear gland is located at the upper, outer corner of the eye.

How the eye works

It secretes a watery fluid that makes up tears. Small ducts drain tears from the lacrimal gland through very tiny openings inside the inner corner of the eyelid. When the eye blinks, the tears are swept across the surface of the eye.

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Tears lubricate the conjunctiva covering the surface of the eye and inner eyelid. Tears also remove dust and debris from the eye and help to prevent infection. The eye socket orbit is a bowl-shaped area made up of bone formed from the skull. It contains the eyeball, muscles, lacrimal gland, nerves, fat and connective tissues. The bone and tissues surrounding the eyeball help to cushion and protect it.

Eye muscles allow the eyeball to move in different directions. These small muscles attach to the sclera near the front of the eye and to the bones of the orbit at the back. The eye and brain work together to allow us to see. The main function of the eye is to collect light and information about what we see. This information is sent to the brain through the optic nerve.

The brain then turns information into a visual image or picture for us to see. If we lose the vision in one eye, we can still see most of what we could see before. The thin, moist layer of tissue that lines some organs and body cavities, including the nose, mouth, lungs, airways, vagina and gastrointestinal GI tract. Call us toll-free at Or write us. We will reply by email or phone if you leave us your details.

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Read more. Presented in partnership with Desjardins. Learn more. Select the text below and copy the link. The eyes The eye is the organ of sight vision. The eyeball The main part of the eye is the eyeball.

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  8. The wall of the eye The wall of the eye is the outer part of the eye that surrounds the ball of jelly-like fluid. Cornea The cornea is the clear, dome-shaped covering at the front of the eye. Uvea The uvea is divided into 3 main parts — the iris, choroid and ciliary body. Iris The iris is the thin, muscular coloured part of the eye. Choroid The choroid is a thin layer of tissue that lies between the sclera and retina.

    Ciliary body The ciliary body is a muscular ring of tissue at the junction of the iris and the choroid. Retina The innermost layer of the wall of the eye is made up of the retina also called the neural tunic. Lens The lens is a transparent disc-shaped structure in the inner part of the eye. Accessory parts of the eye The accessory adnexal parts of the eye include the eyelids, conjunctiva and lacrimal tear glands. Six bands of muscles attach to the eyeball to control the ability of the eye to look up and down and side to side.

    These muscles are controlled by three cranial nerves. Four of the muscles are controlled by the oculomotor nerve cranial nerve III , one muscle is controlled by the trochlear nerve cranial nerve IV and one muscle is controlled by the abducens nerve cranial nerve VI. The Eye Humans are very visual animals Electromagnetic Spectrum Vision First, some specifics about the eye: the human eye is about 2.

    Parts of the Eye Aqueous Humor: Clear, watery fluid found in the anterior chamber of the eye.

    Structure and Function of the Eyes

    Choroid: Layer of blood vessels that nourish the eye; also, because of the high melanocytes content, the choroid acts as a light-absorbing layer. Cornea: Transparent tissue covering the front of the eye. Does not have any blood vessels; does have nerves. Iris: Circular band of muscles that controls the size of the pupil. The pigmentation of the iris gives "color" to the eye. Blue eyes have the least amount of pigment; brown eyes have the most.

    Vision: Crash Course A&P #18

    Lens: Transparent tissue that bends light passing through the eye. To focus light, the lens can change shape by bending. Pupil: Hole in the center of the eye where light passes through. Retina: Layer of tissue on the back portion of the eye that contains cells responsive to light photoreceptors. Rods: Photoreceptors responsive in low light conditions. Cones: Photoreceptors responsive to color and in bright conditions.

    Sclera: Protect coating around the posterior five-sixths of the eyeball. Vitreous Humor: Clear, jelly-like fluid found in the back portion of the eye. Maintains shape of the eye. Hear IT! Take a short on-line, interactive quiz about the eye.