Visual System Part 2 Flashcards
Rod discs contain these proteins
Rhodopsin- responds to mostly blue
Cone discs contain these proteins
Iodopsin- blue, green, red
Discs of photo receptors get created by this organelle
Golgi apparatus
Light diminishes _______ release from receptors
Glutamate
Light converts 11-cis retinal to _______
Trans-retinal
Light stimulates opsin to send signal to
Phosphodiesterase (PDE), which binds to cGMP—>GMP
Lack of cGMP, by PDE attachment results in this action on Na+ channels
Closes Na+ channels.
Function of rods
Peripheral; do not code for color. Night vision. Sensitive to scattered light.
Function of cones
Code for color, concentrated in fovea, spread out thinly to provide peripheral color vision. Sensitive to direct axial light
In order from anterior to posterior: Rods/cones, pigment epithelium, and _______
Choroid
Why are rods/cones against the choroid on the back of the retina?
Waste products created. Blood is supplied by the choroid, and provides oxygen, nutrients, and turnover system for the rods/cones
Light that passes rods/cones is later absorbed by
Melanin in the epithelium. Part of visual acuity. Lessens the impact of light
Blue light generates _______. The eye contains ______ to protect itself from this.
ROS
Melanin
Maintenance of excitability occurs by this
Conversion of trans-retinal to 11-cis-retinal. In the epithelium, Then this cis formation gets taken back to the rods/cones
Epithelial tight junctions controls the passage of these substances
Glucose, Vitamin A, Cl-, H2O
Water and ions return through the retinal pigmented epithelium (RPE) into
choroid veins. Lymphatic passageway, partially to keep fovea avascular
Retinal detachment occurs because of this
Retina contact with retinal pigmented epithelium is not very strong
Macular degeneration is due to these 2 things
Wet- rupture of blood vessel
Dry- build up of cellular waste
Horizontal cells communicate this
From cones/rods to other ones. They determine how active the signal from cones and rods to bipolar cells—->ganglion cells are going to be
Optic tract contains this
Meninges (dura, subarachnoid space with CSF, pia mater)
This CNS glia surrounds the axon of the optic nerve
Oligodendrocyte is the chief myelinating cell in the CNS
Astrocytes are here
Connect axons to the outside of the nerve tract, and connect to blood vessels
Papilledema is edema under this structure
Optic disc. There is increased pressure behind the retina due to high CSF pressure
Papilledema causes this to the veins
Fat tortuous veins form, and axoplasmic stasis of ganglion cells occurs
