Sage Lee, Samantha Alvarez
Dec 31, 2015
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
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 MusclesInferior oblique muscleInferior rectus muscleLateral recuts muscleMedial rectus muscleSuperior rectus muscleSuperior oblique muscleLevator palpeprae muscle
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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