Vision Flashcards
Who has the best thermal vision?
Snakes- great at spotting the heat of prey
Who has the sharpest eyesight?
Birds such as eagles, hawks, and buzzards have eyesight 3-4x sharper than ours
Who has the best underwater vision?
Sharks- can detect a glow that is ten times dimmer
Who has the best mammalian night vision?
Cats - large eyes, see 2x as well as we do in the dark
Who has the best all around view?
Grazing mammals such as horses, gazelles, and zebras have eyes that face sideways
What are the two main types of eyes?
Chambered (ours) and compound (insects, lobsters)
A compound eye consists of ______
thousands of individual photoreceptor units
Iris is responsible for ….
controlling the size of the pupils and thus the amount of light that reaches the retina
A pupil is…..
a hole located in the center of the iris that allows light to enter the retina
The lens is ____
an optical device which transmits and refracts light, converging or diverging the beam
The cornea is …
the transparent front part of the eye that covers the iris, pupil, and anterior chamber
The Retina is….
a light sensitive tissue lining the inner surface of the eye. The optics of the eye creates an image of the visual world on the retina, like film in a camera
Light striking the retina initiates a cascade of ____ and ____ events that ultimately trigger _____. These are sent to various _____ of the brain through the _____ of the optic nerve.
Light striking the retina initiates a cascade of chemical and electrical events that ultimately trigger nerve impulses. These are sent to various visual centers of the brain through the fibers of the optic nerve.
What are the two types of photoreceptor cells in the retina?
Rods (low levels of light) and cones (greater levels of light)
In the scotopic level of light ____ are active.
scotopic - rods
In the mesopic level of light ___ are active
mesopic - both rods and cones are active
In photopic levels of light ___ are active
photopic - cones
In starlight and moonlight, ____ are active
Both rods and cones (mesopic)
The optic chiasm is —
the “Crossing” - part of the brain where the optic nerves partially cross (where half the information from each eye crosses sides)
The optic tract is …
a continuation of the optic nerve that runs from the optic chiasm to the lateral geniculate nucleus
The Edinger-Westphal nucleus controls the _____
pupillary light reflex
The superior colliculus _______
orients the movements of the head and eyes
How is the hypothalamus involved in the visual pathway?
Regulates circadian rhythm
The lateral geniculate nucleus is the _______ for visual information received from the ____
The lateral geniculate nucleus is the primary relay center for visual information received from the retina
The lateral geniculate nucleus is located in the
thalamus, in both hemispheres
Neurons of the lateral geniculate nucleus (LGN) send their axons through ___ ____
optic radiation
What are the two kinds of layers of the lateral geniculate nucleus (LGN)?
Parvocellular layers and Magnocellular layers
Lateral Geniculate Nucleus (LGN): Parvocellular Layers (color, number, function)
4 green parvocellular layers, involved in object processing
The Lateral Geniculate Nucleus: Magnocellular Layers (color, number, function)
Magnocellular- 2, blue, motion
The primary visual cortex is also known as ___ or ____
V1 or the striate cortex
Visual cortex: the extrastriate areas consist of
V2, V3, V4, and V5
The secondary visual cortex is involved in ____
Association - where is it, what is it
What part of the brain is associated with social attention?
STS - superior temporal sulcus
Predictive vision refers to the fact that
faces are processed as a whole, not as parts
Visual pathway grows more complex from the retina to the layers of the cortex. This is known as ___
hierarchical processing
What is the order of visual processing?
Retina –> Optic tract –> Splits at Optic Chiasm –> lateral geniculate nucleus –> visual cortex –> dorsal/ventral pathway
