Chapter 24: Special Senses: Vision Flashcards

Lacrimal Apparatus (External Eye)

Contains lacrimal glands, lacrimal canals, lacrimal sac, lacrimal canaliculi, and nasolacrimal duct.

Lacrimal Sac (External Eye)

Dilated ends of the lacrimal ducts at the nasal ends of the eyes that fill with tears secreted by the lacrimal glands.

Lacrimal Glands (External Eye)

Paired almond-shaped glands, one for each eye, that secrete the aqueous layer of the tear film. They are situated in the upper, outer portion of each eye.

Lacrimal Canals (External Eye)

Also know as the lacrimal canaliculi.

Conjunctiva (External Eye)

Thin, protective mucous membrane lining the eyelids and covering the anterior surface of the eye itself.

Sclera - Fibrous Tunic (Non-vascular)
(Internal Eye)

White opaque portion of the fibrous layer of the eyeball.

Cornea - Fibrous Tunic (Non-vascular)
(Internal Eye)

Transparent anterior portion of the eyeball; part of the fibrous layer.

Choroid - Uvea Tunic (Vascular)
(Internal Eye)

The vascular middle layer of the eye.

Iris - Uvea Tunic (Vascular)
(Internal Eye)

Colored portion of the eye.

Ciliary Body (Internal Eye)

Muscle that controls lens shape, attached to lense

Pupil (Internal Eye)

Opening in the center of the iris through which light enters the eye.

Retina - Sensory Tunic (contains vitreous humor)(Internal Eye)

Neural layer of the eyeball; contains photoreceptors (rods, cones).

Rods (Internal Eye)

For dim light and black and white.

Cones (Internal Eye)

For color.

Bipolar Cells (Internal Eye)

Cells located in the retina the connect ganglion cells and photoreceptors.

Ganglion Cells (Internal Eye)

The output cells of the retina. They indirectly receive their inputs from the photoreceptors and send their outputs to the brain.

Optic Disc (Internal Eye)

Blind spot: the point where the optic nerve enters the retina; not sensitive to light

Macula Lutea (Internal Eye)

A small yellowish central area of the retina that is rich in cones and that mediates clear detailed vision

Fovea Centralis (Internal Eye)

Area on macula lutea that consists only of cones; for acute vision

Lens (Internal Eye)

A transparent, biconvex structure in the eye that, along with the cornea, helps to refract light to be focused on the retina.

Anterior Segment (Internal Eye)

Front third of eyeball, including the cornea, anterior chamber, iris and ciliary body.

Posterior Segment (Internal Eye)

Back two-thirds of the eye that includes the anterior hyaloid membrane and all of the optical structures behind it: the vitreous humor, retina, choroid, and optic nerve.

Aqueous Humor (Internal Eye)

Watery fluid in the anterior segment of the eye.

Vitreous Humor (Internal Eye)

Clear colorless transparent jelly that fills the posterior segment of the eye.

Visual Pathway

Pathway that light travels to the brain to become images.
OPTIC NERVE --> OPTIC CHIASMA --> LATERAL GENICULATE BODY --> OPTIC RADIATION --> PRIMARY VISUAL CORTEX

Optic nerve

2nd cranial nerve that is responsible for seeing

Optic Chiasma

The partial crossover of fibers of the optic nerves.

Optic Tract

A collection of retinal ganglion cell axons stretching from the optic chiasm to the brain stem.

Emmetropy

Normal condition of the eye in which visual images are in clear focus on the retina

Myopia

A condition in which visual images are focused in front of rather than on the retina; nearsightedness.

Hyperopia

A condition in which visual images are routinely focused behind rather than on the retina; commonly known as farsightedness