Structures and Functions of the Eye

Choroid

Vascular layer providing nutrients to the retina

Rectus Muscle

Muscle that moves the eye horizontally

Optic Nerve

Nerve responsible for transmitting visual information to the brain

Superior Oblique

Muscle that turns the eyeball at an angle

Inferior Rectus Muscle

Muscle that pulls the eye downward

Superior Rectus Muscle

Muscle that turns the eye upward

Strabismus

Disorder causing misalignment due to muscle weakness

Lazy Eye

Informal term for strabismus resulting in reduced vision

Diplopia

Medical term for double vision

Sclera

White fibrous layer protecting the eye

Cornea

Transparent layer covering the front of the eye

Ciliary Bodies

Structure responsible for lens shape changes

Suspensory Ligaments

Connective tissue attaching the lens to the ciliary body

Iris

Colored part of the eye controlling pupil size

Pupil

Opening allowing light to enter the eye

Macula Lutea

Area of high cone cell concentration for visual acuity

Fovea Centralis

Central area of the macula lutea with the highest visual acuity

Optic Disc

Blind spot where the optic nerve exits the eye

Retina

Innermost layer containing photoreceptor cells

Pupillary Sphincter Muscle

Muscle contracting to constrict the pupil in bright light

Pupillary Dilator Muscle

Muscle contracting to dilate the pupil in low light

Parasympathetic Control

Regulates pupil size based on light intensity

Sympathetic Control

Involved in pupil dilation in response to dark environments

Blind Spot

Area on the retina lacking photoreceptor cells

Lens

Structure responsible for focusing light onto the retina

Cataracts

Cloudiness or distortion of the eye's lens

Aqueous Humor

Fluid filling the front and back chambers of the eye

Glaucoma

Condition with increased pressure in the eyeball

Concave Lens

Lens that diverges light rays outward

Convex Lens

Lens that converges light rays inward

Accommodation

Eye's ability to adjust focus for near or far objects

Presbyopia

Age-related loss of near vision

Astigmatism

Irregular curvature of the lens or cornea

Farsightedness

Condition where light focuses behind the retina

Near Point Accommodation

Ability to focus on objects close to the eye

Hyperopia

Farsightedness requiring a convex lens for correction

Ciliary Body

Structure containing muscles that control the lens shape

Posterior Chamber

Space filled with aqueous humor behind the iris

Anterior Chamber

Space filled with aqueous humor in front of the iris

Corneal Cloudiness

Loss of transparency in the cornea leading to vision impairment

eye Lens Adjustment

Process of changing the shape of the lens for focusing

Myopia

Nearsightedness, light rays fall in front of retina

Rod Cells

Detect light, more sensitive in low light

Cone Cells

Detect color, best in bright light

Retinal Ganglion Cells

Part of optic nerve, receive impulses from receptors

Rhodopsin

In rod cells, composed of opsin and cis retinol

Photoreceptors

Cells in the retina detecting light stimuli

Transducin

Activated by light, triggers signal cascade in rod cells

Hyperpolarization

Cell becoming more negative in response to light stimuli

Glutamate

Neurotransmitter released by photoreceptors in absence of light

Bipolar Cell

Cell releasing neurotransmitter onto retinal ganglia

Action Potential

Result of neurotransmitter release along optic nerve

Depolarization

Opening of sodium channels causing cell activation

Opsin

Component of rhodopsin activated by light

Phosphodiesterase

Enzyme closing sodium channels in photoreceptor cells

Colorblindness

X chromosome trait affecting color perception

Optic Chiasma

Point where optic nerves partially cross over

Superior Colliculus

Brain structure involved in visual processing

Lateral Geniculate Nucleus

Thalamic nucleus relaying visual information

Occipital Lobe

Brain region processing visual stimuli

Primary Visual Cortex

Brain area interpreting visual information

Association Cortex

Brain region integrating sensory information

Axons

Nerve fibers transmitting electrical impulses

Oculomotor Nerves

Nerves controlling eye movement

Depth Perception

Ability to perceive objects in three dimensions

Midbrain

Brain region involved in visual and auditory processing