Eye Care 4 - anatomy

Eyeball (globe)

The round, fluid-filled main body of the eyeball that houses the structures responsible for vision

adnexa oculi

The accessory structures that surround, protect, and support the function of the eyeball

orbit

The pear - or pyramidal - shaped bone cavity within the skull that houses and protects the eyeball (globe) and its supporting structures

eyelid

a mobile fold of skin that covers and protects the anterior eyeball

palpebral fissure

the open space or elliptical gap between the upper and lower eyelids

medial + lateral canthus

the inner and outer corners of the eye where the upper and lower eyelids meet

lacrimal apparatus

the tear-producing and tear-disposal system of the eye

lacrimal gland

a gland that secretes tears; it lies in the upper outer angle of the orbit

lacrimal punctum

anatomical landmarks that work together to manage tear drainage and define the corners of the eye

canaliculus

passageway for drainage of tears from eyes to tear sac

lacrimal sac

The dilated upper end of the lacrimal duct - the narrow channel that drains tears from the tear sac into the nasal cavity

nasolacrimal duct

The duct through which tears pass from the lacrimal sac into the nasal cavity

meibomian gland

multiple specialized glands in the upper and lower eyelids that secrete the oily part of the tear film

tear film layer (lipid)

the oil layer, which gives the optical surface a smooth base and prevents the aqueous layer from evaporating

tear film layer (aqueous)

The middle water base layer, which provides moisture, oxygen, and essential nutrients while fighting off infection

tear film layer (mucin)

The innermost mucus layer that coats the eye's surface to help the watery layer stick evenly to the cornea

cornea

The clear membrane at the front of the globe that begins the process of focusing the light the eye receives

corneal epithelium (Bowman's membrane)

The outermost corneal layer, which provides defense against infection and injury

corneal stroma

The middle (3rd) corneal layer, which lies under the Bowman membrane and above the Descemet membrane; it contributes to corneal rigidity

Descemet's membrane

The fourth corneal layer that lies above the innermost endothelium and below the stroma; it contributes to corneal rigidity

corneal endothelium

The fifth, innermost corneal layer, which lies under Descemet's membrane; it is composed of a single layer of cells that maintains proper fluid balance within the cornea

limbus

The junction between the sclera and the cornea; marks the transition from the transparent front part of the eye to the opaque white layer

scerla

The outer fibrous tissue of the globe that surrounds the cornea and forms the wall of the eye; protects intraocular components

conjunctiva

a thin, translucent mucous membrane that extends from the outer corneal border over the globe and the inner surface of the eyelid

anterior chamber

The small compartment between the cornea and the iris is filled with a clear, transparent fluid called aqueous humor

posterior chamber

The space between the back of the iris and the front of the vitreous; the crystalline lens is suspended in this chamber, which is filled with aqueous fluid

aqueous humor

The clear, transparent fluid that fills the anterior chamber

iris

The colored circle of tissue that controls the amount of light entering the eye by enlarging or reducing the size of its aperture, the pupil

pupil

The opening in the center of the iris that enlarges or dilates (admitting more light) and reduces or constricts (admitting less light)

ciliary body

a bandlike structure of muscle and secretory tissue that extends from the edge of the iris and encircles the inside of the sclera

ciliary muscle

The muscle fibers in the ciliary body of the uveal tract that are involved in accommodation

ciliary process

a fingerlike extension of the ciliary body that produces aqueous humor

zonules

radial fibers that suspend the lens from the ciliary body and hold it in position

crystalline lens

part of the optical focusing system of the eye, immediately behind the lens

trabecular meshwork

The spongelike structure that filters the aqueous humor from the anterior chamber and controls its rate of flow out of the eye

canal of schlemm

a structure that drains the aqueous humor from the anterior chamber after it has flowed through the trabecular network