Week 4 Flashcards
__________ a camera eye one lense, photo receptors layed behind the one lense. In a simple eye the field of view is very small. But the precision of view is very high.
simple
what is an example of a species with a simple eye
humans, mammals, cephalopods, inverts
The function of an eye is to map the _________________ to a _____________________
angles of incoming light to points on the retina.
Far off light sources produce ________
parallel rays
Light rays that hit the retina at different angles are ______________
effectively parallel
_____________ all points on the retina Map to a different point in space
spatial vision
___________ 1 point in space maps to one receptor
1 to 1 mapping
The location at which the light rays hit the retina is called the ___________
receptor
______________ a simple visual organ of pigment or pigmented cells covering a sensory termination
eyespot
In an eyespot where is the visual epithelium located?
located on one side of the epithelium wall
Does an eyespot have spatial vision?
No spatial vision but light is always visible
__________ an eye consisting of a cup of dark pigment that contains anywhere from a few photoreceptors. In a pigment cup eyes there is no optical system other than the opening of aperture through which light enters the cup
pigment cup
________ extreme version of a pigment cup. The cup itself is very large across with millions of photoreceptors. They have muscles that move the eye and pupils in using diameters. They are significantly more invaginated and open to the seawater
pinhole eye
in a pinhole eye very few photons can travel through making the image ____________ because ___________
better because light s mapped onto the retina precisely,
in a pinhole eye can orientation be determined
orientation can be determined because lots of light can get through.
______ high light on retina precisely. This eye required a pinhole opening. Lens allows a larger opening to facilitate focus
camera eye
Thus small opening allows us to turn Reys into points on the retina.
camera eye
every increment of anatomy makes an eye better this explains _________
eye evolution
The pinhole eye is an excellent example of how physical contains can push ______________
physical specialization
vertebrate eyes have refracting lens with colliery muscle.
these muscle serve to adjust aperture
Unlike simple eyes where receptors are behind one lense, in a compound eye __________________
each receptor has its own lens and all lense are compounded together
compound eyes have lower resolution because the light defeats at
the edge of any lense
most of life uses compound eye due to almost _____________________
360’ resolution
__________ hyper polarize in response to light because NA conductance decreases
vertebrate photoreceptor
________ depolarization because increased sodium conductance
invertebrate photoreceptor
rhodopsin’s actives what
sodium channels
What is the vertebrate pathway
- rhodopsin( transformations light into enzymatic activity)
- engages in signaling cascade
- activated phosphodiesterase which deactivates cGMP
- closed the cGMP activated NA channel
hyperpolarization in vertebrates results in
deactivating cGMP, closing cGMP and activating Na+ channel
__________ rhodopsin activates PLC results in more IP3 and Dag which open a channel and increase sodium conductance
invertebrates
Light deactivates the light current. No light current
falls results in _____________
hyperpolarization
Each photoreceptor is sensitive to fractions of ________________-
wavelength of light
Each of these form different ______________
photoreceptors
The strength of the membrane potential is directly correlated to the ________
color
Our eyes us a ___________ system of light
trichromatic
emission spectra of a firefly peaks at the exact point of spectral sensitivity in ___________
both species
firefly match their own species
this allows for species identification
humans have ___________
3 receptors that cover about 380nm to about 800nm
butterflies are ________ which allows them to see UV spectrum
heterochromatic (4 receptors)
Goldfish can see in IR and UV- ____________the sensory spectrum, more sensitivity to more wavelengths, more discrimination between colors. They can see colors we can not
tetrachromatic fractionate (4 receptors)
__________ is highly directional and can reflect specifics. This allows for greater discrimination of the motion/ direction of butterflies
UV light
_____________ surfaces reflect sunlight and polarized lens filter plane of polarization in particles of sunlight. Light is a particle and a wave
polarized light
__________ are parallel in photoreceptors. Our photoreceptor cilia are scrambled not aligned preventing us from seeing polarized
microvilli
__________ maximize surface area. In one photoreceptor, all of them are parallel
microvilli
In one receptor, all the microvilli are in parallel because this allows
it to be intrinsically sensitive to the 3 vectors of light in eyes like a variety of polarized lenses
____________ changing the orientation changes the amplitude and the us wavelength
plane of polarization
how does eye location indicated predator or prey
eyes located on the side indicates the animal is likely prey while forward facing indicates predators
________________ result in the deformation of ion channels. There is then a recording of action potentials not Vm
stretch receptors
The receptor potential of a sensory receptor is determined by
-depolarization is driven by sensory stimuli not sodium. They still occur in the presence of TTX
receptor potentials are a slow process and are driven by
G protein receptors
