5536817
Description
Flashcards by Alice Nugu, updated more than 1 year ago
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Created by Alice Nugu
almost 8 years ago
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| Question | Answer |
| liquid the eye is surrounded by | aqueous and vitreous liquid |
| ciliary muscle | adjusts lens |
| accomodation range | - reflex of the eye when focusing - NEAR VISION -Ciliary muscle CONTRACT - Thicker lens - suspensory ligaments SLACK |
| unaccomodated range | CM relaxes - thin lens SL tense |
| can the retina be seen through the a device? | Yes, using the ophthalmoscope we can see the retina due to light receptors (ie. bc there isl ight there) |
| myopia | short-sightedness;light rays focus on front of retina |
| hyperopia | hyper(long) - farsightedness; Light rays focus beyond the retina (picture the digram) |
| what are the 5 classes of neurons? | photoreceptors, bipolar cells, ganglion cells; horizontal cells and the amacrine cells |
| what is the quicket route to the brain from the retina (neuronal) | PR > BC > GC> optic nerve (the brain) |
| 3 layers of the retinal nucleus: inner nucleus layers; | BCs, HCs, ACs nuclei |
| 3 layers of the retinal nucleus:GC layer | retinal nucleus layer; gc layer has gc nuclei |
| 3 layers of the retinal nucleus: outernucleus layers | PRs nuclei |
| what are rods? | PRs sensitive to light and dark colours. good for darkness. |
| what are cones? | PRs, that are colour sensitive. good in light area. - light causes a great change ie. hyperpolarisation: voltage decreases. |
| gmp-gated channels are activators for what? | Na+ channels OPEN, more NA and CA in neuron |
| what happens to rods when they are exposed to light? | light exposure decudes the cGMP why? bc amt of light is depedent on the amt of agtes opened. |
| when are PRs active? | active? when they reach threshold. |
| active threshold of cones? | - when in the dark, it is inactive. - only active when there is light. |
| rods also do what? | these photoreceptors also detect movement |
| there are more cones in this area of the macular; why? | there is a higher amt of cones for focusing (high acuity) ie. for reading. - higher spatail freq - higher resolution |
| the optic disc | nicknamed the 'the blind spot' bc we cannot see anything there. - why? no PRs |
| how many photopigments to rods have? | 1 pp |
| there are 3 different cones; each with what to allow them to work? | 3 diff cones for 3 diff pps /wavelengths these are long, medium and short (RBG pps) |
| protanopia | loss of LONG wavelength (red pps) |
| deutenopia | loss of medium w/l (blue pps) |
| on-center GC | activate on center when there is light |
| off-center GC | activate OFF center whenb it is dark |
| what NT is released in cones? | GLUTAMANE |
| what happens to more release of glutamane? | hits ganglion cells and fires more rapidly. |
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