Topography and vasculature B7 Flashcards
What are the first 3 cells of the visual pathway?
1st: Photoreceptors
2nd: Bipolar cells
3rd: Ganglion cells
Light energy is transformed into a neural signal
phototransuction
SIgnal is modified within the ______.
retina
The inner 9 layers are collectively referred to as the sensory or ________.
Neural retina
The outermost layer 10th is the ___.
RPE
What are the 10 layers
ILM: inner limiting membrane RNFL: retinal nerve fiber layer RGCL: retinal ganglion cell layer IPL: Inner plexiform layer INL: Inner nuclear layer OPL: outer plexiform layer (part of photoreceptor) ONL: outer nuclear layer ELM: external limiting membrane PRL: photoreceptor layer (part of photoreceptor) RPE: retinal
If it is outer retina it is dealing with what?
photoreceptors
If inner retina is what?
2nd order or 3rd order neurons distributing signal
Highest density of cone photoreceptors?
FOvea
S cones M cones L cones what wavelength is for what colors?
Short= blue Medium= green Long= red
The role of the photoreceptor is to absorb light photons and convert them into an electrochemical event (nerve signal) through the process of ___________.
phototransduction
No ___ cones in center of fovea
S
There are no ______ in the fovea
rods
Rod photoreceptor morphology, how many? dim or bright? contain what pigment?
92-120 million
dim vision (scotopic)
All contain photopigment rhodopsin
Peak density is in a ring 4.5 mm outside fovea
Cell involved in processing, piggy backing
Amacrine cells
Radial glial cells of retina
Müller cell, provide structural support and buffering environment
THese cells are found in retinal nerve fiber layer, wrap around vessels and give support.
Astrocytes
IN glaucoma what cells star to die off because of the pressure?
REtinal ganglion cells
Retinal thickness ranges from what to what?
80 um to 320 um
Fovea is 150- 200um
At equator 120-180 um
at ora serrata 80um
Dentate processes of the ora serata are on what side of retina?
nasal, think serrated knife
Dense population of cone receptors
Designed for color vision and fine detail discrimination
Central retina
Dense population of rod photoreceptors
Designed for night vision and motion detection
Peripheral retina
Dense packing of cones makes them appear rod like in structure are in what?
Foveola
Cone inner fibers that are oriented obliquely within the fovea are called ___________.
Henle’s fiber layer (aka= outer plexiform layer)
This extends 0.5 mm from foveal rim
Highest accululation of bipolar and retinal ganglion cells. Rod photoreceptors reach peak density
Parafovea
1.5 mm from the parafoveal rim
Axons of Henle’s fiber layer resume their vertical orientation.
Perifovea
Outer retina what do we think of?
photoreceptors
10-20% have this artery, comes from ciliary vessels, and supplies macula.
Cilioretinal artery (supplies ganglion cells around macula)
what is positioned more nasal, Central retinal artery or vein, CRA or CRV?
central retinal artery is more nasally
The CRA loses its __________- upon entering the eye, which distinguishes it from muscular arteries of the same size found elsewhere in the body.
tunica elasticum
Tunica elasticum is replaced by what?
tunica media
____________ is the outermost layer of blood vessels and is thicker in veins.
Tunica adventitia
At the very center of the fovea is what?
an avascular zone
