Chapter 2-Anatomy and Physiology Flashcards
(121 cards)
Cornea
The clear membrane at the front of the globe that begins the process of focusing light the eye receives.
Globe/Eyeball
The eye, without its surrounding structure.
Iris
The colored circle of tissues 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).
Crystalline Lens (Lens)
Part of the optical focusing system of the eye immediately behind the iris.
Vitreous/Vitreous Body
The clear, jelly-like substance that fills the space behind the lens.
Retina
The inner lining of the posterior segment of the eyeball; consists of a layer of light-sensitive cells that convert images from the optical system into electric impulses sent along the optic nerve for transmission to the brain.
Optic Nerve
The nerve that carries electric impulses to the brain’s visual cortex, where they are integrated to produce the sensation of sight.
Axial Length of the Globe
The length of the eyeball from front (cornea) to back (retina), measured through the optical center.
CCT
Central thickness of the cornea.
Pachymetry
An instrument that measures the distance between the corneal epithelium and the corneal endothelium (corneal thickness).
Refractive Power
The ability of a substance to refract light expressed quantitatively by either its index of refraction or it’s refractivity.
Diopters
The unit of measure of the power of a lens.
Adnexa
The tissues and structures surrounding the eye, includes the orbit, extraocular muscles, eyelids, and lacrimal apparatus.
Orbit
The bony cavity in the skull that houses the globe, extraocular muscles, blood vessels, and nerves.
Blowout Fracture
An injury caused by blunt force applied to the eye, creating pressure that fractures the orbital bones.
Extraocular Muscles
The six muscles that attach to the outside of the globe and control it’s movements.
Medial Rectus Muscle
Extraocular muscle attached to the inner (nasal) side of the globe; function is to move the eye inward toward the nose (adduction).
Lateral Rectus Muscle
Extraocular muscle attached to the outer (temperol) side of the globe; moves the eye outward toward the ear (abduction).
Superior Oblique Muscle
Extraocular muscle attached to the upper side of the globe; three functions are to rotate the eye downward and outward and to rotate inward.
Inferior Oblique Muscle
Extraocular muscle attached to the underside of the globe; three functions are to move the eye upward and outward and to rotate the eye outward.
Superior Rectus Muscle
Extraocular muscle attached to the upper side of the globe; three functions are to elevate the eye, turn the eye inward, and rotate the eye inward.
Inferior Rectus Muscle
Extraocular muscle attached to the underside of the globe; three functions are to move the eye downward and inward toward the nose (adduction) and rotate the eye outward.
Binocular Vision
The blending of the separate images seen by each eye into one image; occurs when both eyes are directed toward a single target and perfectly aligned.