40 Vision Flashcards
Incoming light is focused on:
fovea
As an image enters the eye, it is:
- refracted by the cornea
- inverted through the pupil
- refracted by the lens
- projected onto fovea
The lens refraction abilities are controlled by:
ciliary muscles (under SNS and PNS control)
Function of sclera?
protective layer for the retina and the choroid
Function of choroid?
vasc bed which provides blood flow and nutrients to the photoreceptors and RPE cells
The retinal blood flow is supplied by:
- central retinal artery (enters through optic nerves)
2. choroid
The cell bodies of the photoreceptors are located in:
And project to:
outer nuclear layer
outer plexiform layer
The photoreceptors signal through:
to:
through the outer plexiform layer to the bipolar cells
Cell bodies of bipolar cells are located:
in the inner nuclear layer
The final layer of neurons in the retina are:
retinal ganglion cells (located in the ganglion cell layer)
Function of retinal pigmented epithelial cells?
support the photoreceptors and provide nutrients
Line outermost surface of retina?
photoreceptors
Function of interneurons?
help in convergence of the image from the millions of photoreceptors to hundreds of bipolar cells to tens of ganglion cells
Types of interneurons?
horizontal cells and amacrine cells
Coalesce to form optic nerve head?
ganglion cell axons
Blind spot =
optic nerve head
Structure of fovea?
radially displaced retinal layers
allows for minimal distortion of the image
Main functions of retinal pigmented epithelial cells?
- separate the vascular choroid from the neural retina
- phagocytose rod outer segments every 10 days
- absorb some of the light that comes to the photoreceptors
Macular degeneration results when:
blood vessels damage the RPE + break through their barrier –> grow into macular region of the eye
Light detection/transduction occurs in:
outer segment of rods
What are spherules?
synaptic vesicles in rods
Cones are (shorter/longer) and (bigger/smaller) than rods.
shorter, smaller
How is color “seen”?
recognized by a unique combo of L-, M- and S-cones
Blue cones?
S
Green cones?
M
Red cones?
L