The Eyeby: Elora Zavala

and

Hallesha Williams

General Facts of the EyePurpose: to help see what is around you.

About 1 inch in diameter

Made up of 3 layers Outermost

CorneaSclera

Middle LayerChoroidCiliary BodyIris

InnermostRetina

CorneaClear, dome shaped surface that covers the iris,

pupil, and anterior chamber.

Most powerful lens that has no blood vessels

Contains Five LayersEpitheliumAnterior Elastic LaminaSubstantia Propria Posterior Elastic LaminaCorneal Endothemlium

ScleraWhite protective part of the eye

Has Four layersEpiscleraStromaLamina FuscaEndothelium

ChoroidLayer of blood vessels between the retina and

scleraSupplies blood to retina

Ciliary BodyWhere aqueous humor is produced

Attached to lens by zonules

Also controls focus by changing the shape of the lens.

IrisColored part of the eye that is surrounded by

sclera

Ring of muscle fibers located behind cornea and in front of lens. Consists of two layersPigmented Epithelial CellsPigmented Fibrovascular Tissue (Stroma)

Connected to a sphincter muscle that controls dilation and contraction of pupil.

Helps protect the sensitive retina

RetinaThin nerve membrane that detects light entering

the eye

Retinal Blood VesselsSupply blood to the retina and are visible to the

eye

Located in the choroid just beneath retina

Retinal Pigment Epithelium

Layer of cells between the retina and choroid

Melanin in the RPE gets rid of waste products

PupilThe opening in the iris.

Pupil size is seen by the iris contraction or dilations.

Crystalline LensLocated behind the cornea, normally clear

Light passes through pupil to lens

Small muscles attached to lens

Vitreous HumorJelly like, thick liquid that fills the eye to help

maintain its shape

Located between the the lens and retina

Drains back into the blood through canals of schlemm

Canals of SchlemmLocated around the perimeter of the iris

Allows vitreous gel (or aqueous humor) to drain back into blood stream

Vitreous CavityThe space between the lens and retina filled

with gel.

Visual FieldsRetina of each eye has two sections

Nasal Retina (Yellow)Temporal Retina (Green)

Optic NerveThe nerve at the back of the eye that carries

visual information from the eye to the brain.

Blind spot comes from the optic disc located near the optic nerve.

MaculaNear the center of the retina at the back of the

eyeball.

This part of the eye gives us our 20/20 vision.

FoveaIndentation in the center of the macula

Is responsible for our highest visual acuity

The center of our central vision

UveaMiddle vascular layer of the eye

Three Parts IrisCiliary BodyChoroid

ZonulesHundreds of string like fibers that hold in

position

Enable it to change shape for near or distant vision

Fluid Chambers of the Eye Anterior Chamber

Space between cornea and iris filled with aqueous humor.Aqueous Humor

Fluid produced in the eye

Posterior Chamber Space between iris and

lens filled with aqueous humor.

Muscles of the EyeCiliary Muscle

Changes the shape of the lensFlattens lens for distance visionContracts for closer visionProduces aqueous humor.

Muscles of Eye cont. Muscles located OUTSIDE of the eye

Superior Rectus - rotates the eye upwards

Inferior Rectus - rotates the eye downwards

Medial Rectus - rotates the eye towards the nose

Lateral Rectus - rotates the eye towards the ear

Superior Oblique - aids in upward movement

Inferior Oblique - aids in downward movement

Muscles of the Eye: cont.

Accessory Organs

Eyelashes/EyebrowsSpecialized hairs that protect the eye for dust and

insects

ConjunctivaThin, clear membrane located on the rim of

bottom inner eyelids and covering front of the eye. Cells produce mucous to help lubricate the eye Inflammation is conjunctivitis, commonly known as

pink eye.

Accessory Organs: cont.Eye Socket

Cone shaped bone cavity that protects the eyePadded with fatty tissue

EyelidsProtects and lubricates the eyeLines the inner edge of the eyelid.

Accessory Organs: cont.Tarsus

Supports the eyelid skinGives the lid its-

StrengthShapePlace for muscles to attach

Accessory Organs: contLacrimal Sac

Drains tears and other debris from eye

Lacrimal GlandsReleases tears and other protective fluid onto the

surface of the eyeKeeps cornea from being dehydrated

Accessory Organs: cont.Visual Cortex

Part of the brain that processes and combines visual information both eyes and converts it into sight

Visual Axis Imaginary line drawn from the center of the pupil

to the center of fovea.Fixation Point comes from the visual axis

Accessory Organs: cont.Optic Chiasm

First part of the brain to receive visual input Each eye takes a slightly different picture of the

world

Neurons

Neurons: cont.Pigment Epithelium

Shields the retina from excess incoming light

Rods/ConsAKA PhotoreceptorsFound in the retina. Convert light into signals that can stimulate biological

processes.

Cranial Nerves (involved with sight)

Optic (II)Sensory Sensory fibers transmit impulses associated with

sense of vision

Oculomotor (III)Motor fibers transmit impulses to muscles that

raise eyelids, move the eyes, adjust amount of light that enters the eye, and focuses the lenses

Cranial Nerves cont. Trochlear (IV)

Motor fibers transmit impulses to muscles that move the eyes

OpthalmicSensory fibers transmit impulses from the surfaces

of the eyes, tear glands, upper eyelids, etc.

Abducens (VI)Motor fibers transmit impulses to the muscles that

move the eys

Visual ReceptorsVisual receptor cells are a layer of rods and

cones (the photoreceptor cells I mentioned earlier) that aid in visual inside of retina

Each rod or cone contains a pigment that absorbs a certain type of wavelength better than others

RefractionMakes image formation possible

When light travels through the lens it’s path is bent or refracted.

The eye itself, sees an image upside down but the signal to the brain flips it right side up.

PigmentsIodopsin

a violet light-sensitive pigment in the cones of the retina of the eye that is responsible for color vision

Rhodopsin

The pigment sensitive to red light in the retinal rods of the eyes, consisting of opsin and retinene. Also called visual purple

Dark VS Light VisionDark

Rods are responsible

Only can tell between black and white shade.

Provides enhanced sensitivity

Light

Cons are responsible

Eyes can see best in

Responsible for color and fine detail.

Convergent VS Divergent Waves

Convergent Waves

Eyes begin to look inward

AKA Crossed Eyed

Divergent Waves

Eyes begin to look outward

AKA Lazy Eye

Stereoscopic VisionAKA Binocular Vision

Provides information to the brain to find the depth of the visual scene which is also known as 3D sight

EYE SEE YOU!

http://www.youtube.com/watch?v=gvozcv8pS3c

Works Citiedhttp://www.aoa.org/x5352.xml

http://www.allaboutvision.com/eye-exam/refraction.htm

http://hyperphysics.phy-astr.gsu.edu/hbase/vision/rfreye.html

http://hubel.med.harvard.edu/book/b41.htm

http://faculty.stcc.edu/AandP/AP/AP2pages/Units14to17/unit15/retina.htm

http://www.99main.com/~charlief/Blindness.htm

http://www.webmd.com/eye-health/structures-of-the-eye

http://www.yorku.ca/eye/blndspot.htm

http://www.ophthobook.com/chapters/anatomy

http://www.stlukeseye.com/anatomy/ciliary.html

http://www.gopetsamerica.com/anatomy/iodopsin.aspx

http://www.vetmed.vt.edu/education/curriculum/vm8054/eye/rhodopsn.htm

http://www.shreveporteyeclinic.com/humaneye_anatomy_details.asp

http://www.ncbi.nlm.nih.gov/pubmed/1492139