Flashcards
the eyes
Cards in this deck (46)
- 1what does the pupil dosmall opening to let light in
black because contains pigment able to pick up every light frequency - 2what does the iris dosurrounds the pupil
contains muscles that change the size of the of the pupil opening- controls the light that can get into the eye - 3what holds the lens in placeciliary muscles
- 4what is the effect of contractions of the ciliary muscleschanges the shape of the lens
-helps focus an image at the back of the eye - 5what causes the blind spotthis is a region in the centre of the retina called the optic disk
-this is where the optic nerve leaves the eye
-there are no photoreceptors in this region - 6what are the names of the 2 types of photoreceptors on the eye-cones
-rods - 7which of the 2 photoreceptors is most sensitive to lightrods by up to 1000 times
during periods of reduced light (night) rods are the only receptors that are able to detect light - 8what is the opsin contained in the rodrhodopsin
- 9what effect does the presence of light have on the rods-closure of sodium ion channels that leads to hyper polarisation as cell becomes more neg.
-bipolar cells become more negative (snaps to the rod) - 10what cell is responsible for most of the light detection in daylight conditionscones
- 11what differs between the cones and rods-cones contain 3 different forms of opsin that allow them to detect colour
-red
-blue
-green - 12how does this signal reach the brainphotoreceptor > horizontal cells > bipolar cells > amacrine cells > ganglion cells > optic nerve
- 13what happens at the optic chiasmsome axons from each retina cross to the opposite side
- 14—
- 15how is light transduce into neural responses by the cellphotos are absorbed by specialised molecule called a retinal
-changes the conformation triggering processes within the cell - 16what does the receptive field of a ganglion cell showthere are 2 components
-excitatory centre and the inhibitory surround - 17what form of input is more common in the LGNtop-down
- 18how are visual signals transmitted (what pathway do these signals take)retina> LGN> occipital> parietal> inferotemporal cortex
- 19how is this signal transducede
- 20what is emmetropia?no reflective error because the refractive power of the eye is matched to the length of the eyeball
- 21what is the fovea-small depression in the retinal
-high concentration of cones
-centre of an object is aligned with the fovea - 22what is the eccentricitythe distance between a position on the retina and the centre of the fovea
- 23what is the purpose of the iris-muscular diaphragm surrounding the pupil
-regulate the light entering the eye - 24what is myopiainability to see distant object clearly
-a.k.a nearsightedness - 25what is the optic nervebundle of nerve fibres that carry impulses from the retina to the lateral geniculate nucleus and other structures
-contais 1 million ganglion cells - 26what is the peripheral retinaarea of the retina outside of the fovea
- 27what is photopic visionvision under well lit conditions
- 28what is presbyopiainability of the eye to to accommodate during the hardening of the lens and the weakening of the ciliary muscles
- 29what is reflectance and what is the reflectance curve-percentage of light reflected from a surface
-percentage of light that is reflected from a surface as a function of wavelength - 30what is scotopic vision?vision under low light conditions
- 31visual anglethe angle of an object relative to an observers eyes-
- 32what is the absorption spectruma plot of the amount of light absorbed by a visual pigment versus wavelength of light
- 33what is an amacrine cell?neuron that transmits signal laterally in the retina
-synapse with bipolar and ganglion cells - 34what is centre surround organizationarrangement of a neurons receptive fields in which one area is surrounded by another are
stimulation of the centre has the opposite response to the surrounds - 35literal geniculate nucleus (LGN)a structure in the thalamus that receives the input from the retinal ganglion cells
-has input and output connections with the visual cortex - 36what cells laterally inhibithorizontal and amacrine
- 37what are m cells?ganglion cells that have a large centre surround receptive field
-indifferent to wavelength and adapt quickly - 38what is the optic chaism?the part of the brain where the optic nerves cross over
-immediately below the thalamus - 39what are p cells?ganglion cells that have a small centre surround receptive field
-sensitive to the wavelength of light
-adapt slowly - 40what is phototransductionlight energy is transduced into electrical energy in the rods and cones in the retina of the eye
- 41what is retinalmolecules that is bound to membrane proteins in photoreceptors that can absorb photons
- 42what is a retinopic map?a map of the structure in the visual system
- 43what is spontaneous activityneural activity in the absence of an explicit task
-a.k.a resting state activity - 44striate cortexthe primary visual cortex
-also called V1
broadmann area 17 - 45what is the superior colliculusarea of the brain involved in the control if the eye movements and other visual behaviours
received 10% of the retinal ganglion cells that leave the eye in the optic nerve - 46what is the term for shortsightednessmyopia
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- Flashcards on the eyes , created by Samantha Bruce on 09/05/2018.
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- Samantha Bruce · May 2018
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- May 10, 2018
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