Vision Flashcards
___ is the ability to bend light
Refractive power
Measured by: Diopters
____ is the refractive power of the eye
59 diopters
2/3 by the cornea (fixed refractive power)
1/3 by the lens (variable refractive powerr)
The ciliary muscles are ___ (relaxed, tensed) when the lens becomes flat and there is an increased tension from suspensory ligaments
relaxed
Ciliary muscles are contracted if the lens is spherical and there is decreased tension from suspensory ligaments
The optic nerve is composed of ___ that combines together
ganglion cell’s axons that combines together
___ type of retinal cell that prevents light scattering, converts 11cis retinal to all-trans retinal. damage of this is involved in macular degeneration, retinal detachment, and albinism
Pigment Epithelial Cells
This type of retinal cell is absent in the optic disk. It is associated with color blindness.
Receptor cells (Rods and cones)
The location in which the rods are most concentrated
Parafoveal region
This type of retinal cell are contrast detectors
bipolar cells
This type of retinal cell maintains the internal geometry of the retina
Muller cells
This type of ganglion cell (output cells of the retina) is responsible for color, form, fine details
P cells
M cells is for movement and illumination
During nighttime, this receptor cell is more active
Rods - more sensitive to low-intensity light (nighttime, black and white vision)
Cones - more sensitive to high intensity light (Daytime, colorful)
The conversion 11 cis retinal to All-trans retinal leads to the ____ (opening, closure) of Na channels leading to ___ (depolarization, hyperpolarization) resulting to decreased glutamate production.
closure of Na Channel leads to hyperpolarization!
Hyperpolarization causes the action potential in vision!
Decrease glutamate leads excitation and depolarization of the INHIBITORY METABOTROPIC GLUTAMATE RECEPTORS
The three cell types that detect shape and orientation of figures
- Simple cells - responds to bars of light
- Complex cells - responds to moving or edges of light
- Hypercomplex cells - respond to lines with particular length and to angles
When light strikes the eye, the activity of this increases
transducin
the lens is held by ____
suspensory ligament (zonula fibers)
[Refractive disorders]
myopia: light converge ___ of retina
in front
[Refractive disorders]
myopia: the eyeball is ___
long
[Refractive disorders]
myopia: the corrective lens is ____
biconcave
a long eyeball needs a ___ corrective lens
biconcave
[Refractive disorders]
hyperopia: the eyeball is ____
short
[Refractive disorders]
hyperopia: the light rays converge ___ the retina
behind
[Refractive disorders]
hyperopia: the corrective lense is
convex
the eyeball of a person whose vision is corrected by a convex lens is ___
short
Age at which age-related loss of accommodation can happen
> 40 years old
inability to read newspaper in elderly people can be due to failure of contraction of the ___
ciliary body
this relaxes when a person is looking at a far object
ciliary
this relaxes when a person is looking at a near object
suspensory ligament
___ layer is where the ganglion cells combine to form the optic nerve
ganglion cell layer
[retinal cell]
involved in macular degeneration, retinal detachment, and albinism
pigment epithelial cells
[retinal cell]
converts 11 cis retinal to all trans retinal
pigment epithelial cells
[retinal cell]
cells affected in color blindness
rods and cones
What happens to the acuity when
many rods synapse on a single bipolar cell
rod acuity decreases
What happens to the sensitivity when
many rods synapse on a single bipolar cell
rod sensitivity increases
What happens to the acuity when
few cones synapse on a single bipolar cell
high acuity of cones
What happens to the sensitivity when
few cones synapse on a single bipolar cell
sensitivity of cones lowers
[retinal cell]
are interneurons. form local circuits. form local circuits with bipolar cells
amacrine, horizontal cells
[retinal cell]
maintains internal geometry of the retina
muller cells
[retinal cell]
seen in retinal glial cells
muller cells
[retinal cell]
ganglion cell involved in illumination and movement
M cells
[retinal cell]
axons form the optic nerve
ganglion cell
[retinal cell]
output cell of the retina
ganglion cell
[retinal cell]
active in daytime vision
cones
[retinal cell]
active at night
rods
[site of lesion: right side, guess the affected area]
non-homonymous bitemporal hemianopia
optic chiasm
[site of lesion: right side, guess the affected area]
contralateral homonymous hemianopsia
geniculate tract
[site of lesion: right side, guess the affected area]
meyers loop
superior left homonymous quadrantanopia
[site of lesion: right side, guess the affected area]
pie in the sky
superior left homonymous quadrantanopia
[site of lesion: right side, guess the affected area]
pie on the floor
inferior left homonymous quadrantanopia
[neurophysio of the vision]
the closure of Na channels due to decrease in cGMP leads to
hyperpolarization
[neurophysio of the vision]
hyperpolarization leads to a ____ glutamate release
decrease
[neurophysio of the vision]
what converts 11-cis retinal to all trans retinal?
light
[neurophysio of the vision]
before transducin activation all trans retinal will initially first become
metarhodopsin
[neurophysio of the vision]
activation of phosphodiesterase leads to ___
decrease in cGMP
[neurophysio of the vision]
this activate phosphodiesterase
transducin
[neurophysio of the vision]
the activity of this increases when light strikes the eye
activity of transducin
The center of the receptive field is formed by ___
receptor cells connected to ganglion cells
the receptor cells and ganglion cells are connected by ___ cells
bipolar
the surround of receptive field of the ganglion cells is formed by ____
receptor cells
the receptor fields that form the surround of the receptive field are connected by
horizontal cells
[cells in visual cortex]
___ cells respond to bars of lights
simple cells
[cells in visual cortex]
___ cells respond to moving bars or edges of light
complex cells
[cells in visual cortex]
___ cells respond to lines with particular length
hypercomplex cells
[cells in visual cortex]
___ cells respond to curves/angles
hypercomplex cells
[cells in visual cortex]
name the 3 types of cells that detect shape and orientation in the visual cortex
simple cells
complex cells
hypercomplex cells
