Sage Lee, Samantha Alvarez

Layers of the EyeOuter layer

ScleraCorneaIrisLens

Middle layerUvea

Contains the blood vesselsInner layer

Retina Rods Cones

Optic nerve

Fibrous TunicThe outer, fibrous

layer composed of the sclera and the cornea

The cornea: smooth, clear glass-like transparent region made of loose connective tissue that protects the eye

CorneascleraThe Sclera: the “white of the eye”, forming a

supporting wall for the eye

Vascular Pigmented TunicThe iris: circular

muscle that controls the size of the pupil

Ciliary body: responsible for secretion of aqueous humor

Ciliary Muscle: responsible for accommodating lens

Ciliary body and ChoroidChoroid: layer

of blood vessels providing nutrients to the retina

Pupil: controls amount of light entering the eye

Lens: a structure that helps focus light on the retina

The nervous tunicThe retinas major

regions consists of;Optic papilla: joint of

optic nerve and retinaFovea centralis with

macula lutea: area of greatest visual acuity

Pigment Epithelium

Cells of the eyePhotoreceptorsNeurons: Bipolar,

Ganglion cells, Centrifugal cells, and amocrine

Supporting cells: Muller’s cells and Neurological cells

Cones

Eye glandsMeibomian glandsLacrimal Gland

Components of Retina9 layers:Layer of

rods and cones

Optic Nerve

FoveaMaculaGanglion

Layer

Eye MusclesInferior oblique muscleInferior rectus muscleLateral recuts muscleMedial rectus muscleSuperior rectus muscleSuperior oblique muscleLevator palpeprae muscle

Eye SecretionsVitreousDrusenAqueous Humor

Neurons and Visual ProcessPhotoreceptors

RodsCones

Bipolar NeuronAmacrine CellsGanglion CellsOptic Nerve

Bipolar NeuronAxon extends from one side, dendrite from

the otherFound also in the nose and ear

Used for sense of smell and hearingForm in middle layer of the retina

Amacrine CellsLocated at the inner

plexiform of the retina (IPL)

Transfer message between bipolar cells and ganglion cells

Classified into two typesBy dendrite

morphology and stratification (formation and appearance)

Ganglion Cells and Optic NerveGanglion cells

Transmit the message to the optic nerve

Optic nerveLongest part of processReaches a far part in

the brain where the image is processed Processing is done in the

lateral geniculate body Output is sent to the

striate cortex so we can see the “picture”

Visual ReceptorsRods ConesLocation: retinaThin projection at

terminal endsApprox. 100 millionMore sensitive to lightNerve fibers converge

causing blurry outlines

Location: retinaShort, blunt projections3 different kinds to

detect colorRed, blue, green

Approx. 3 millionSingle fibers, no

convergence. Create sharp images

Visual Receptors Cont.Vision and the receptors only stimulated by

lightEach receptor sends a small portion of the

big picture to the brainThe brain puts it all togetherEpithelial pigment absorbs light not taken in by

receptors Epithelial pigment and pigment of choroid coat

keep light from reflecting off of surfaces in the eye Pigment layer stores vitamin A

Helps receptor cells to synthesize visual pigments

● Refraction○ occurrs when light rays travel

through through the curved, clear front surface of the eye(cornea).

● Convergent vs. Divergent waves ○ Converging waves: light waves

that come together from different directions and have a common meeting point on the lens of the eye.

○ Divergent wave: light waves that come from different directions, and once it hits the lens, continues to travel in different directions.

Interpreting Sight

Interpreting Sight Cont.● Convergent vs. divergent lenses

● Converging lens(convex)● directs rays of light to a point at the optical center or axis

of the lens● thick across the middle and thin at the upper and lower

edges● Diverging lens(concave)

● directs light away from the optical center or axis of the lens

● thin across middle and thick at the upper and lower edges

Interpreting Sight Cont.● Dark vs. Light vision

○ Pupil expands and contracts depending on the amount of light, and could physically block out light form the eye

○ Cone cells can perceive color in bright light.

○ Rod cells perceive black and white images and work best in low light.■ contains Rhodopsin

● it is the chemical that the rods use to absorb photons and perceive light.

Interpreting Sight Cont.● Stereoscopic vision

● The single perception of a slightly different image from each eye ● how we detect depth

perception● perceives distance, depth,

height, and width of objects● brain puts together the

pictures from both eyes into one vision ● brings the three

dimensional vision

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