Neuro - Visual 1
The blind spot is also called the ____
optic disk
Rods have _____ (more or less) disks than cones do
more
Rods have a _____ (higher or lower) photopigment concentration than cones
higher
Rods are ____ (more or less) sensitive to light than cones are
more
Approximately how many rods do we have?
100 million
Approximately how many cones do we have?
5 million
Only cones operate at ____ lighting
photopic
Both rods and cones operate at ____ lighting
mesopic
Does the peripheral retina contain a higher or lower concentration of rods to cones, as compared the central retina?
higher
The peripheral retina has a ____ (high or low) ratio of photoreceptors to ganglion cells
high
True or False: Rods and cones are found in both the peripheral retina and the central retina
false
The central retina is specialized for ______ vision
high resolution
The area of the retina specialized for high visual acuity is known as the _____
fovea
_________ of cells above photoreceptors reduces scattered light
lateral displacement
An impairment in perception of long wavelengths is known as ________
protanopia
True or False: Colourblindness is often due to a defiency in the absorption of photopigments rather than a decrease in number of them
true
Does retinitis pigmentosa affect the central or peripheral vision?
peripheral
Which disease results in a loss of central vision, but maintains peripheral vision
macular degeneration
Do photoreceptors depolarize or hyperpolarize in response to light?
hyperpolarize
Photoreceptors release _____ (less or more) neurotransmitter in the dark
more
Trans retinol is transported into the pigment epithelium via a(n) _____ protein
IRB
Trans retinol is converted to _____ in the pigment epithelium
cis retinal
Does Calcium increase or decrease sensitivity to light?
decrease
decreases
cGMP channels ____ (open or close) in the presence of light
close
A decrease in Calcium will ____ (increase or decrease) the activity of Guanylate cyclase
increase