Ophthalmology Anatomy and Physiology Review

Vocabulary practice flashcards covering ocular anatomy, eye tunics, corneal physiology, lens alterations, photoreceptors, and ophthalmic reflexes based on lecture notes.

Fibrous tunic

The outer layer of the eye, comprising the cornea, limbus, and sclera.

Vascular tunic

The middle layer of the eye (also known as the uvea), comprising the iris, ciliary body, and choroid.

Neurosensory tunic

The inner layer of the eye, formed by the retina.

Corneal epithelium

The outermost, 6-to-10 cell layer of the cornea that is highly regenerative.

Corneal endothelium

A minimally regenerative inner monolayer of corneal cells that actively pumps fluid out of the stroma; dysfunction leads to corneal edema.

Iris

The pigmented vascular structure containing dilator and constrictor muscles that regulates the amount of light entering the eye by adjusting pupil size and shape.

Ciliary body

The structure contiguous with the iris that produces aqueous humor via active transport involving carbonic anhydrase, generates intraocular pressure, and facilitates lenticular accommodation.

Uveitis

Inflammation of the uvea (vascular tunic) of the eye.

Iridocorneal angle (ICA)

The anatomical angle in the anterior chamber containing the trabecular meshwork and pectinate ligaments through which aqueous humor drains.

Choroid

The heavily pigmented and richly vascular posterior section of the uvea that supplies oxygen and nutrients to the outer retina and photoreceptors.

Cataract

An opacity of the lens or its capsule caused by abnormal lens fibers, leading to a stage-dependent decrease in vision.

Nuclear sclerosis

A normal aging alteration of the lens resulting from the accumulation of normal fibers in the nucleus, maintaining normal vision.

Lens zonules

Fibers attached at the equator of the lens that hold it in position; dysfunction or breakdown leads to lens subluxation or luxation.

Vitreous

The largest structure of the eye by weight and volume, consisting of a gel-filled chamber located behind the lens.

Rods

Photoreceptors with high sensitivity responsible for night vision and motion detection.

Cones

Photoreceptors with low sensitivity responsible for day vision, color vision, and visual acuity (detail).

Optic nerve (CN II)

An extension of the central nervous system composed of the axons of retinal ganglion cells (RGCs).

Menace response

A learned response (developing after $12$ weeks of age) testing CN II and CN VII, where the normal reaction is a blink and/or retraction of the globe via CN VI.

Pupillary light reflex (PLR)

An involuntary autonomic reflex involving CN II (afferent) and CN III (efferent) used for lesion localization; it is not a direct test of vision.

Strabismus

An abnormal deviation of the globe away from its normal visual axis.

Tear film

A protective, three-layer fluid film composed of a lipid layer (meibomian glands), aqueous layer (lacrimal glands), and mucin layer (conjunctival goblet cells).

Third eyelid

A semilunar fold of conjunctiva surrounding a T-shaped cartilaginous support with a gland at its base, responsible for globe protection, tear production, and tear distribution.

Epiphora

Overflow of tears onto the face, commonly caused by obstruction of the nasolacrimal apparatus.

Extraocular muscles (EOMs)

Muscles that control movement of the eye: Dorsal Rectus (CN III), Ventral Rectus (CN III), Medial Rectus (CN III), Lateral Rectus (CN VI), Dorsal Oblique (CN IV), and Ventral Oblique (CN III).