35 terms

Ocular Anatomy and Physiology

Ocular anatomy and physiology as it relates to the Ocular Adnexa, the eye as an optical system, other related structures, and the visual pathway.
Length of the eye
24 mm
where the cornea and sclera meet
Corneal diameter
12 mm
Refractive surfaces
lens = 1/3
cornea = 2/3
Nerve Fiber Layer (NFL)
made of axons that converge to make one cable (the optic nerve)
Components of the Lens
Capsule, cortex, and nucleus (outer to inner order)
Optic disk color
Cataracts disease
the aging of the lens (not permanent)
Glaucoma disease
the loss of peripheral vision and affects the optic nerve (permanent)
Components of Ocular adnexa
Eyelids, extraocular muscles, lacrimal apparatus, and orbit
distribute the tear film across the cornea
Meibomian glands
oil secreting, prevent tear evaporation
eyelid closure muscle
eyelid raising muscle
the thin transparent membrane that lines the inner eyelids and the surface of the eyeball (excluding the cornea)
Palpebral fissure
the space vertically between open eyelids, 6-8 mm
Function and Components of Lacrimal Apparatus
Lacrimal gland, punctum, canaliculus, and sac (clockwise from top), responsible for tear production for lubrication and hydration
2 inch deep skull cavity, lined by orbital bones. Contains eyeball and its muscles, blood supply, nerves, and fat.
Transparent structures
pre-corneal film, cornea, aqueous, lens, vitreous, and retina
Cornea function and layers
clear, round membrane at front of globe (avascular), which focuses light rays. (front to back) Epithelium, bowman's membrane, stroma, descemet's membrane, and endothelium
white, fibrous outer tissue layer that forms the main structure of the globe
Anterior Chamber
space between cornea and iris filled with aqueous, holds up the cornea
Anterior chamber angle
corners of anterior chamber, responsible for aqueous outflow by ant. cham. angle, trabecular meshwork, and canal of schlemm
the colored structure behind the cornea, and in front of the lens
the opening in the center of the iris, dilated (widened) by dilator muscle, and constricted by the sphincter muscle
Uveal tract
pigmentation and blood vessels; composed of iris, ciliary body, and choroid
behind the iris and in front of vitreous, suspended by zonules attached to ciliary body. focuses on object as they come closer to the eye: accommodation
transparent jelly behind the lens responsible for holding up the eye
thin, neural tissue which lines between vitreous and sclera, extending to the brain. receives the image before sending to brain for interpretation
retina photoreceptor cells that interpret night vision and black and white (scotopic)
retina photoreceptor cells that interpret color vision and sharp central vision
Optic Nerve
in back of the eye connecting eyes to brain, takes retinal images and converts them into neural impulses to go to brain
Visual Pathway
Wiring from optic nerves to occipital cortex in brain: optic chiasm, optic tracts, optic radiations, and occipital cortex
Seven Orbital Bones
Frontal, Sphenoid, Zygomatic, Maxilla, Ethmoid, Lacrimal, and Palatine
Moll and Zeis
glands at base of each cilia (eyelash): sweat and sebaceous (respectively)