The Human Eye

Vocabulary flashcards about the human eye based on lecture notes.

Sklera

The outer, strong, inelastic layer of the eye made of connective tissue; serves as attachment points and supports the eye, responsible for the shape of the eye.

Ciliary Body

Contains the ciliary muscle and is the thickened anterior part of the choroid; ciliary muscle contracts or relaxes to change the tension on the suspensory ligaments.

Suspensory Ligaments

Ligaments connected to the ciliary body; hold the lens in position during accommodation, tension changes to alter the shape of the lens.

Iris

Colored part of the eye with an opening in the middle called the pupil; contains two types of muscles to control pupil size, controls the amount of light entering the eye through the pupil mechanism.

Aqueous Humor (Watervog)

Watery fluid found in the space between the cornea and the lens; maintains the shape of the cornea and plays a small role in the refraction of incoming light.

Pupil

Opening in the iris; allows light to enter the eye.

Lens

Elastic, biconvex structure behind the pupil of the iris, held in position by suspensory ligaments; transparent, changes shape to allow the eye to focus on near and far objects, allows light through.

Cornea

Transparent continuation of the sclera at the front of the eye, it is convex (bulges outwards); transparency allows light to enter the eye, the convex shape causes refraction of incoming light rays, allows light through to the eye and causes refraction to form an image on the retina.

Vitreous Humor (Glasvog)

Jelly-like substance found behind the lens; maintains the shape of the eyeball and plays a small role in the refraction of incoming light.

Sklera

Tough, white, inelastic layer that covers the eye at the back; protects the structures inside the eye and allows the eye to maintain its shape.

Choroid

Dark-colored layer containing blood vessels and pigments; pigments absorb light to prevent reflection, blood vessels provide nutrients and oxygen to retinal cells.

Retina

Innermost layer of the eye, contains rods and cones, which are light-sensitive; rods respond when light intensity is low and are responsible for night vision as well as peripheral vision, cones respond to bright light and provide sharp, clear color vision, neurons conduct impulses from rods and cones through the optic nerve to the cerebrum.

Blind Spot

Small area on the retina, below the fovea; no rods or cones, thus no vision, area where blood vessels enter the eye, area where the optic nerve leaves the eye, area of no vision and provides oxygen and nutrients to inner parts of the eye, impulses are taken to the cerebrum for interpretation.

Fovea (Geelvlek)

Small indentation at the back of the eyeball, contains most cones; area with the clearest (sharpest) vision.

Optic Nerve

Carries electrical impulses from the retina to the brain; Brain interprets image, causing a blind spot where there are no cones and rods in the area.

Binocular Vision

The ability to focus on an object with both eyes, forming a single image; allows for three-dimensional vision, depth perception, and precise movement.

Accommodation

The ability of the eye to change the shape of the lens to ensure a clear image always falls on the retina.

Pupil Mechanism

Process by which the diameter of the pupil is changed to control the amount of light that enters the eye; the iris controls the amount of light that enters the pupil through circular and radial muscles.

Nearsightedness (Bysiendheid)

A vision defect caused by an eyeball that is too long, and is corrected with diverging lenses.

Farsightedness (Versiendheid)

A vision defect caused by the eyeball being too round, corrected with converging lenses.

Astigmatism

A vision defect where the eye cannot focus an object's image on a single point on the retina, caused by an uneven cornea.

Cataracts

A vision defect where the lens becomes cloudy due to the denaturing of the lens proteins, obstructing light passage.