| front |
back |
revisions |
lasted changed by |
history |
| color visoin |
-similar to rhodopsin, except sensitive to specific wavelengths
-blue cones, green cones, and red cones (sensitive to yellow light) |
0 |
mcs5109 Sun, 19 Oct 2008 20:36:38 GMT |
 |
| dark adaptation |
-generates more sensitive rhodopsins |
0 |
mcs5109 Sun, 19 Oct 2008 20:35:23 GMT |
|
| light adaptation |
-light bleaches photopigments (retinal + opsin)
-sensitivity to light reduced |
0 |
mcs5109 Sun, 19 Oct 2008 20:35:23 GMT |
|
| rhodopsin |
2 molecules: opsin (protein embedded in membrane of rod disks)
retinal: vit A derivative |
0 |
mcs5109 Sun, 19 Oct 2008 20:35:23 GMT |
|
| phototransduction |
-similar for rhodopsin (rods) and 3 color pigments (cones)
in dark:
-retinal binds snugly to opsin
-cGMP is high
-open Na+ channels
-rod stays depolarized at -40mV
-continuous release f neurotransmitter (glutamte), inhibitoyr for bipolar cells
in light:
-light contacts rod
-rhodopsin changes from cis to trans + opsin
-(similar rxn in cones, but sensitive to blue, green, red wavelengths)
-free opsin activates transducin (G-protein) that activates phosphodiesterase (cGMP to 5'GMP)
-closes Na+ channels
-Na+/K+ ATPase pump dominates
-hyperolarizes to -70mV
-decreases glutamate to bipolar cells
-no more inhibition |
0 |
mcs5109 Sun, 19 Oct 2008 20:35:23 GMT |
|
| occular dominance columns |
-alternating right/left eye info projects to cortex |
0 |
mcs5109 Sun, 19 Oct 2008 20:24:56 GMT |
|
| macula |
-projects to huge amount of cortex |
0 |
mcs5109 Sun, 19 Oct 2008 20:24:56 GMT |
|
| macular sparing |
-lesions at end of path do not affect macula, which has already diverged
-macular sparing tends to occur with lesions beyond the LGB |
1 |
mcs5109 Mon, 20 Oct 2008 00:32:12 GMT |
|
| to oppipital lobe |
lateral: top portion of left or right field
medial: bottom portion of left or right field |
0 |
mcs5109 Sun, 19 Oct 2008 20:24:06 GMT |
|
| lateral geniculate body |
-in thalamus
-synaspe onto neurons leading to visual cortex in occupital lobe |
0 |
mcs5109 Sun, 19 Oct 2008 20:24:06 GMT |
|
| optic tract |
-axonds from nasal (L) and temporal (R)
-lesions affect both eyes |
0 |
mcs5109 Sun, 19 Oct 2008 20:24:06 GMT |
|
| optic chiasm |
-asons from nasal retinas cross over |
0 |
mcs5109 Sun, 19 Oct 2008 20:24:06 GMT |
|
| optic nerve |
-conducts axons from each eye |
0 |
mcs5109 Sun, 19 Oct 2008 20:24:06 GMT |
|
| lateral or temporal retinas |
-central vision |
0 |
mcs5109 Sun, 19 Oct 2008 20:24:06 GMT |
|
| medial or nasal retinas |
-peripheral vision |
0 |
mcs5109 Sun, 19 Oct 2008 20:24:06 GMT |
|
| pursuit mvt |
-eyes remain fixed on moving object and track it
-can't voluntarily do this
-not jerky mvt |
0 |
mcs5109 Thu, 16 Oct 2008 08:22:19 GMT |
|
| saccade mvt |
-successive fixation points
-watching telephone poles in cars
-reading |
0 |
mcs5109 Thu, 16 Oct 2008 08:22:19 GMT |
|
| ganglion cells |
-W: smallest, rod info, esp. mvt
-X: most common; cone; color info
-Y: largest, least common, rapid mvt, changes in intensity |
0 |
mcs5109 Thu, 16 Oct 2008 08:20:44 GMT |
|
| horizontal cells |
-inhibitory to surrounding photoreceptor cells
-determine image representation on ganglion cells
-on center/off surround
-on surround/off center |
0 |
mcs5109 Thu, 16 Oct 2008 08:20:44 GMT |
|
| colors |
-blue cone: blue hv
-gren cone: green hv
-red cone: YELLOW hv; we're less sensitive to red |
0 |
mcs5109 Thu, 16 Oct 2008 08:20:44 GMT |
|
| color blindness |
-X-linked
-defect in one or more of 3 types of cones |
0 |
mcs5109 Thu, 16 Oct 2008 08:20:44 GMT |
|
| glaucoma |
-excess intra ocular pressure
-too much aqueous humor in anterior |
0 |
mcs5109 Thu, 16 Oct 2008 08:00:27 GMT |
|
| cataract |
-cloudy lens |
0 |
mcs5109 Thu, 16 Oct 2008 08:00:27 GMT |
|
| astigmatism |
-uneven thickness of cornea |
0 |
mcs5109 Thu, 16 Oct 2008 07:56:38 GMT |
|
| presbyopia |
-in people >40
-loss of accommodation |
0 |
mcs5109 Thu, 16 Oct 2008 07:56:38 GMT |
|
| hyperiopia |
-far sighted
-eye too short
-focal point falls behind the retina
-convex lens correction
-presbyopia in aged lens |
0 |
mcs5109 Thu, 16 Oct 2008 07:56:38 GMT |
|
| myopia |
-(near sighted)
-eye too long
-focal point falls before the retina
-concave lens correction |
0 |
mcs5109 Thu, 16 Oct 2008 07:56:38 GMT |
|
| pigmented epithelium |
-supplied most of blood
-absorbs excess light rays that escape photoreceptors
-prevents distracting light from reflecting inside the eye |
0 |
mcs5109 Thu, 16 Oct 2008 07:50:20 GMT |
|
| ganglion layer |
-axons form optic nerve
-receive info from bipolar cells |
0 |
mcs5109 Thu, 16 Oct 2008 07:50:20 GMT |
|
| order of retina |
-blood vessels
-ganglion layer
-amacrine cells
-bipolar cells
-horizontal cells
-rods and cones
-dark pigment epithelium layer |
0 |
mcs5109 Thu, 16 Oct 2008 07:50:20 GMT |
|
| vitreous humor |
-much larger chamber than anterior chamber
-clear, gelantinous matrix that helps maintain shape of the eyeball |
0 |
mcs5109 Thu, 16 Oct 2008 07:33:36 GMT |
|
| canal of schlemm |
-where aqueous humor normally flows out
-in anterior chamber of eye
-elevated eye pressure usually associated with too much aqueous eye humor
-have to reopen canal of schlemm! |
0 |
mcs5109 Thu, 16 Oct 2008 07:33:36 GMT |
|
| aqueous humor |
-fills anterior chamber
-low-protein plasma-like fluid secreted by ciliary epithelium supporting the lens |
0 |
mcs5109 Thu, 16 Oct 2008 07:33:36 GMT |
|
| anterior vs. posterior chambers |
-anterior filled with aqueous humor
-small
-posterior filled with vitreous humor
-big |
0 |
mcs5109 Thu, 16 Oct 2008 07:33:36 GMT |
|
| fovea or macula lutea |
-cone concentration
-regions of retina with most acute vision
-center of visual field |
0 |
mcs5109 Thu, 16 Oct 2008 07:33:36 GMT |
|
| optic disk or blind spot |
-radiates small arteries and veins
-in retina
where neurons of visual pathway form optic nerve (II) and exit the eye
-blind spot
-where optic nerve and blood vessels leave the eye |
0 |
mcs5109 Thu, 16 Oct 2008 07:33:36 GMT |
|
| Accomodation triad |
-eyes adjust the shape of lens to keep object in focus
near vision:
-ciliary body contracts
-lens rounds up
-eyes converge
-pupils constricts
relaxed suspensory ligaments
far:
-ciliary body relaxes
-lens flattens
-contracted suspensory ligaments |
0 |
mcs5109 Thu, 16 Oct 2008 07:13:10 GMT |
|
| retina |
-light-sensative lining of eye
contains photoreceptors |
0 |
mcs5109 Thu, 16 Oct 2008 07:13:10 GMT |
|
| lens |
-bends light to focus it on the retina
-bend incoming light to focus on retina |
0 |
mcs5109 Thu, 16 Oct 2008 07:13:10 GMT |
|
| ciliary body |
-contraction alters curvature of the lens
-when contracts, muscle gets round (to see close)
-when dilates, flattens (to see far) |
1 |
mcs5109 Thu, 16 Oct 2008 07:11:33 GMT |
|
| choroid |
-pigmented epithelium blood supply
-the vascular layer of the eye lying between the retina and the sclera |
1 |
mcs5109 Sun, 19 Oct 2008 19:26:41 GMT |
|
| pupil |
where light passes through
-changes the amount of light entering the eye |
0 |
mcs5109 Thu, 16 Oct 2008 07:00:36 GMT |
|
| iris |
- |
0 |
mcs5109 Thu, 16 Oct 2008 07:00:36 GMT |
|
| sclera |
-outer wall of eyeball
-composed of connective tissue |
0 |
mcs5109 Thu, 16 Oct 2008 07:00:36 GMT |
|
| cornea |
-where light enters
-transparent disk of tissue on anterior surface
-continuation of sclera |
0 |
mcs5109 Thu, 16 Oct 2008 07:00:36 GMT |
|
| eye muscles |
-6 extrinsic eye muscles |
0 |
mcs5109 Thu, 16 Oct 2008 07:00:36 GMT |
|
| eyelids |
-close over anterior surface of eye |
0 |
mcs5109 Thu, 16 Oct 2008 07:00:36 GMT |
|
| conjunctiva |
-membrane that covers the sclera (white part of the eye) and lines the inside of the eyelids. |
1 |
mcs5109 Mon, 20 Oct 2008 00:26:13 GMT |
|
| UV light |
-we see 380-760nm |
0 |
mcs5109 Thu, 16 Oct 2008 06:47:39 GMT |
|
| Trigeminal V |
-motor to general sensation
-eye, teeth, mouth muscles
-general facial sensation
-three branches on face |
0 |
mcs5109 Thu, 16 Oct 2008 06:47:39 GMT |
|
| Abducens VI |
-motor only to lateral rectus |
0 |
mcs5109 Thu, 16 Oct 2008 06:47:39 GMT |
|
| Trochlear IV |
-motor only to superior oblique |
0 |
mcs5109 Thu, 16 Oct 2008 06:47:39 GMT |
|
| Oculomotor III |
-iris, ciliary body control
-all muscles except superior oblique, lateral rectus
-motor only, to most extrinsic eye muscles |
0 |
mcs5109 Thu, 16 Oct 2008 06:47:39 GMT |
|
| Optic nerve II |
-for vision
-only nerve to conduct visual impulses
-sensory only, light sensation |
0 |
mcs5109 Thu, 16 Oct 2008 06:47:39 GMT |
|
| nerves for eye |
II
III
IV
VI
V |
0 |
mcs5109 Thu, 16 Oct 2008 06:47:39 GMT |
|
| Vision |
-contains photoreceptors
-2 million neurons (more than all other senses combined)
-inverted image on retina
-sends signals to brain |
0 |
mcs5109 Thu, 16 Oct 2008 06:47:39 GMT |
|
