EENT FHS Structure Function

Sclera

tough outer coat that protects the eye, maintains its shape, and anchors the eye muscles

Iris

adjusts pupil size to control how much light enters the eye

Cornea

transparent front surface that protects the eye and provides most of its light refraction

Corneal epithelium

forms a protective barrier against microbes and injury

Bowman’s Layer

tough layer that supports and protects the corneal surface

Corneal stroma

provides corneal strength and transparency through organized collagen

Descemet’s membrane

supports the corneal endothelium as its basement membrane

Corneal endothelium

pumps fluid out of the cornea to keep it clear

Lens

changes shape to focus light onto the retina for near and distant vision

Conjunctiva

lubricates and protects the inner eyelids and anterior sclera

Retina

converts light into electrical signals for vision

Choroid

supplies blood to the outer retina and absorbs scattered light

Lacrimal gland

produces tears that lubricate, protect, and clean the eye

Lacrimal ducts

carry tears from the lacrimal gland onto the eye’s surface

Nasolacrimal duct

drains tears from the lacrimal sac into the nasal cavity

Vitreous humor

clear gel that maintains eye shape and supports the retina

Anterior chamber

space between the cornea and the iris containing circulationg aqueous humor

Posterior chamber

space behind the iris and in front of the lens that receives newly produced aqueous humor

Canal of Schlemm

collects aqueous humor from the trabecular meshwork and drains it toward the vein

Optic disc

exit point for the optic nerve; lacks photoreceptors and creates the blind spot

Macula

provides detailed central vision, with greatest acuity at its central fovea

Eyelids

protect the eye and spread tears across its surface during blinking

Eyelashes

intercept debris and trigger protective blinking when touched

Glands of Moll

modified sweat glands associated with eyelashes that contribute to eyelid secretions

Glands of Zeis

secrete oil into eyelash follicle to lubricate the lashes

Meibomian glands

produce the oily tear-film layer that reduces tear evaporation

Tarsal plate

dense connective tissue that supports eyelid shape and houses meibomian glands

Optic nerve

carries visual signal from retina to brain (CN II)

Cones

provide color vision and sharp detail in bright light

Rods

provide dim-light vision and help detect peripheral movement

Aqueous humor

nourishes the cornea and lens and helps maintain intraocular pressure

Drainage angle

junction of cornea and iris where aqueous humor enters the trabecular drainage system