RPE Flashcards
How is the RPE and photoreceptor outer segment aligned?
apex to apex
What is in the neural retina?
photoreceptors, bipolar, ganglion, horizontal and amacrine cells
Where is the ocular ventricle?
The potential space between the RPE and POS
After lens induction begins, the _____ _____ collapses back onto itself. The inner invagination becomes the _______ while the outer part becomes the _______
After lens induction begins, the optic vesicle collapses back onto itself. The inner invagination becomes the neural retina while the outer part becomes the RPE
The basement membrane of the RPE becomes ____ ____ during development. The basement of the neural retina becomes the ____ ____ ____
The basement membrane of the RPE becomes Bruch’s membrane during development. The basement of the neural retina becomes the inner limiting membrane
Where would you find microvilli on the RPE?
the apical portion. Microvilli envelope the photoreceptors
The epithelial cells of the Blood Retinal barrier are bound together by _____ _____ and divide the cells into apical halves that face the _______ and basal halves that face the ______
The epithelial cells of the Blood Retinal barrier are bound together by tight junctions and divide the cells into apical halves that face the receptors and basal halves that face the choroid
What gives the RPE its black appearance?
Pigment granules
What is proliferative vitreoretinopathy?
Pigment granules separate from the RPE as free cells and appear as “tobacco dust” in the vitreous. Cells then settle and form contractile fibrocellular membranes
What part of the retina uses the most energy?
The outer segments
Photoreceptor survival depends on having _____ and _____ in large quantities
blood and glucose
What are the four extreme properties that the choroid has developed to meet the demands of the photoreceptors?
- High permeability
- High throughput of blood - more blood faster
- High oxygen levels
- No auto-regulation
Name the two problems created by the thin and sparse central retinal circulation (made necessary since it lies in the path of light)
- Very little oxygen reserve
2. Small vessel diameter
What are the five functions of the RPE? (RPEAM)
Retinal barrier
Photoreceptor renewal and light absorption
Environment protection against superoxides
A… Vitamin A metabolism and storage
Matrix synthesis
What are the two aspects of the blood-retinal barrier?
- Tight junctions of the endothelial cells of the CRC
2. Tight junctions of the RPE keeping blood out of the retina
The fenestrated choriocapillaries permit leakage of _______
protein
Protein concentration in front of the RPE is ____ while the concentration in the ECS behind the RPE is ____
Protein concentration in front of the RPE is low while the concentration in the ECS behind the RPE is high
The RPE can absorb up to ___% of the aqueous secretion in a day
50%
What are the factors preventing RPE/retina detachment?
- Oncotic fluid gradient
- Finger-like folds of the RPE
- Interphotoreceptor matrix
Due to the high membrane fluidity required by the retina, the ____ bonds of the _____ _____ _____ make the retina highly susceptible to superoxide attack.
Due to the high membrane fluidity required by the retina, the double bonds of the unsaturated fatty acids make the retina highly susceptible to superoxide attack.
Hurler’s syndrome is the buildup of _____ molecules due to an improperly functioning degrading _____
Hurler’s syndrome is the buildup of GAG molecules due to an improperly functioning degrading enzyme
Photoreceptors are degraded by _____ and ____
Photoreceptors are degraded by phagocytosis and autophagy
A single RPE cells is responsible for phagocytosing ____ or more rods
10
Define autophagy
Self-digestion by a cell through the action of enzymes of the same cell
