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, م7: BIOS252 Exam 3 Review Guide
BIOS252 EXAM 3 REVIEW
Structures of the e ye
Visible light based on w avelength
Layers of the eye – divide the ey e into ant erior and post erior sections
o Fibrous tunic
Sclera – whites of the e yes; made of dense i rregular conne ctiv e tissue;
where e xtrinsic eye muscles a ttach
Cornea – less str ong but more tr ansparen t than the scler a allowing light
to pass thr ou gh
o Vascular tunic
Choroid - beg ins with the center o f the optic nerve and ext ends to the
choroid; mos tly made of connective tissue and blood vesse ls
Ciliary body – cont ains three s tructures
Ciliary muscles – responsib le fo r changing the shape of the lens
Ciliary process – s ecretes aqueous humor
Zonular fiber s – connect the lens to the ciliary body
Iris
o Re tina
Photoreceptor layer (rods and cones)
Bipolar cell layer
Ganglion cell layer
Horizontal cell layer
Amacrine cells
o Anterior chamber (cavity) – aqueous humor
o Vitreous chamber – vitreous body
Visual path ways
Physiology of vision
o Refraction – the bending of light when it passes through a clear substance
o Light will pass through the cornea, it is then refracted by the aqueous humor , next
it passes through the pupil that focuses the light onto the lens. The lens will then
accommodate (contract and thicken or relax and flatten) which will bend the light
further as it then enters the vitreous chamber and focuses on the retina (on the
fovea centralis – the area of sharpest visual acuity).
o Photoreceptor cells will then send the signal to the retina; through t he optic disc
(place where the optic nerve exits the eye); to the optic nerve; the optic chiasm;
optic tracts; thalamus; optic radiations; and lastly to the occipi tal lobe
Olfaction
Olfactory chemoreceptor cells send the signal to olfactory nerve, olfactory bulb, olfactory
tracts, limbic system, and temporal and frontal lobes
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