Chapter 3: Perception Flashcards
Which sense has the most dedicated area in the brain?
vision has more cortical area devoted to its perception
Light is based on an _____ continuum
EMR Spectrum
light vision deices make use of ____ light waves to detect heat
infrared
the image appears _______ when it gets projected onto the ____
appears upside down when it gets projected back on the retina
the portion of the retina dedicated to color perception is called the ___
fovea
what photoreceptor cells allow the fovea to detect color?
cones
center of visual field
fovea.
____ acts as a filter for light coming in
cornea
pupil
regulates how muhc light gets passed into the eye
iris
color bant, contains muscles to constrict and dilate the pupil
the ___ bends light to focus ir on the back of the eye
the lens
when elderly people cannot focus on objects, its most likely because:
the lens gets less flexible and cannot focus on objects.
the ___ acts as a projective screen, and is comprised primarily of _____ cells.
the RETINA acts as a projective screen, and is comprised primarily of PHOTORECEPTOR cells.
photoreceptor cells respond to ______, and turn it into a ____-signal
respond to light energy, and turn it into an electrical (NEURAL) signal
rods and cones convert the light stimulus into a neural signal, which is conveyed to the ____, which leave the eye through the ______ to the back of the brain.
rods and cones convert the light stimulus into a neural signal, which is conveyed to the GANGLION CELLS, which leave the eye through the OPTIC NERVE to the back of the brain.
the optic nerve are made of axons of _____.
ganglion cells.
what is the blind spot of the eye
the optic nerve
T/F: the optic nerve contains rods and cones
false. Only ganglion cells, which get their inormation from the rods and cones.
General route of light stimulus
cone/rods —> bipolar cells –> ganglion cells —> optic nerve
Myopia
nearsightedness.
Hyperopia
farsightedness/
as older people lose the flexibility of their lens, they generally suffer from:
hyperopia.
what about the tissue makes the retina so special compared to other eye structures?
it is actually composed of a thin layer of NEURAL TISSUE (ganglion and bipolar cells) lining the back of the eye
the ____ contains a large quantity of cones but has very little rods
the fovea
the periphery of the retina contains a lot of ____ and very little amount of _____
a lot of rods, not many cones.
Why does the optic nerve act as our blind spot?
because there are no photoreceptors, only axons and ganglia.
T/F: we have more cones than rods
false. WE have more rods than cones
what is the general mechanism behind vision loss?
dying out of photoreceptors
macular degeneration mechanism
destruction of cones in the fovea, we cannot see things directly in front of us, we only see the periphery
retinitis pigmentosa
destruction of peripheral rod cells. only see the center of the visual field.
a person can only see whats directly in front of them, but cannot see ther person sitting directly beside them. what condition might they have?
they might have retinitis pigmentosum.
photoreceptor that is responsive to bright light, allowing us to see fine detail
cone cells.
photoreceptor that is more responsive to dim light, mainly used for night vision
rods.
the outer segment of the photoreceptor contains _____ that responds to light energy and intiates the neural signal
the outer segment of the rods and cone contains PIGMENT that responds to light energy
how do rods and cones react to light? What must happen in order for the photoreceptors to function after exhaustion?
rods and cones contain pigment segments that respond to light energy and initiates the neural signal by separation of their two parts from each other.
In order for a rod/cone to trigger another neural signal via segment separation, the two parts must come together in order to receive more light.
Testing light sensitivity (recall logarithim of sensitivity vs time in dark graph): which photoreceptor more light-sensitive?
light sensitivity is tested by putting a person in a dark environment and measuring the time it takes for their vision to adapt to the darkness.
Initially, your eyes adapt to seeing color and depth in the dark. Around 7 minutes, your eyes will no longer adapt to seeing color in the dark. However, the rods will continue to get sensitive over 30 minutes, you will be able to see more and more in the dark (just not the color super well).
Rods are therefore more sensitive to light than cones
Why does it take longer for rods to reach peak sensitivity in the dark?
it takes time for the rod parts to come back together and recover after being exposed to light.
it takes 30 minutes in the dark for all the rods to recover (because some were activated in the light).