Unit 2: Visual System Flashcards
What is the structure that makes up the visual center?
Macula lutea
What receptors is the macula lutea comprised of?
Cones because it’s the area of high visual acuity
What is the structures that is a depression in the center of the macula lutea?
Fovea centralis
The fovea centralis is made of what?
Foveola (cones only)
Because this is where visual acuity of foveola that is the highest
What is the peripheral border of the functional retina called?
Ora serrata
There is an area of convergence of fibers of ganglion cells that form the optic nerve. What is this area called?
Optic papilla or the optic disc
This is medial (nasal) and superior to the macula
What is the retinal “blind spot” that has no rods or cones?
The optic papilla or optic disc.
This is where the fibers of ganglion cells converge to form the optic nerve. That’s why there are no rods or cones.
What is the name of the neurons of the retina?
Bipolar cells
The convergence of many rods to one bipolar cell results in:
Summation
The rod system provides for vision of low resolution/acuity and also provides for vision in low light conditions.
10 rods/bipolar cell near macula lutea
100 rods/bipolar cell near ora serrata
Neurons that innervate bipolar cells are called:
Ganglion cells
What part of the retina is best suited for low resolution vision, low light vision?
Peripheral retina
Because it mostly contains rods
What part of the retina is best suited for color vision, high resolution vision?
Macular retina
Because it is comprised mostly of cones and very little or no convergence of bipolar cells on rods.
What do axons of ganglion cells of the retina form?
Optic nerves
Fibers from nasal halves of each retina decussate here (temporal fibers, which do not decussate)
Optic chiasm
Fibers within this structure carry visual data from contralateral visual field:
Optic tracts
The right optic tract carries visual data from the ___ visual field
Left
Fibers within the right optic tract are from ganglion cells located in the:
Right (nasal) half of the left retina
Right (temporal) half of the right retina
Optic tracts project into the:
Lateral geniculate body/nucleus (LGB/LGB) of the thalamus
What nucleus relays neurons for visual data?
LGB/LGN (thalamus)
What is the pathway of vision to the cortex from the optic tracts?
LGB neurons send axons to posterior limb of internal capsule and then to the cerebral cortex on the medial aspect of the occipital lobe
Meyer’s loop relays visual information from the ________ of the visual field
Contralateral upper quandrant
What initiates the processing of visual data?
Primary visual cortex (V1)
where is the primary visual cortex (V1) located?
Upper and lower banks of calcarine sulcus (occipital lobe)
Corresponds with Brodmann map area 17
Primary Visual Cortex maintains retinotopic organization. Where is the macular visual field located in the Primary Visual Cortex (v1)?
Posterior 1/3 of visual cortex
Primary Visual Cortex maintains retinotopic organization. Where is the peripheral visual field located in the Primary Visual Cortex (v1)?
Anterior 2/3 of visual cortex
Primary Visual Cortex maintains retinotopic organization. Where is the contralateral lower quadrant of the Primary Visual Cortex (v1)?
Upper banks fo calcarine sulcus
Primary Visual Cortex maintains retinotopic organization. Where is the contralateral upper quadrant in the Primary Visual Cortex (v1)?
Lower banks of calcarine sulcus
What is the thing that functions to allow for conscious awareness of visual stimuli?
Primary Visual Cortex (v1)
What would a lesion of the cortex adjacent to calcarine sulcus (v1)?
Cortical blindness