Physiology Or RPE And Retinal Blood Barrier Flashcards
Apical side of RPE
Photoreceptor side
Basal side of RPE
BM of RPE from Bruchs
Where does general light absorption occur
Melanin in RPE
Blue light absorption
Supplemented by late in and zeaxanthin in photoreceptors
Most dangerous light for RPE
Blue light
Outer retina exposed to
Oxygen rich enovironment
Outer retina and oxidative damage
Susceptible to it since it is in the presence of the choriocapillaris blood supply
Line of defense against oxidative damage to the retina
RPE
Transepithelial transport RPE
- Transport from photoreceptors to blood
2. Transport from blood to the photoreceptors
Apical side of RPE
Photoreceptors (subretinal space between RPE and photoreceptors)
Basolateral side of RPE
Blood
Removal of water from apical side
The transport of water is driven by an active transport of Cl- from the retina to blood side
What happens when going from photoreceptors to blood
- Removal of water from apical side
2. Removal of lactic acid from apical side
Degeneration of RPE, bulls eye shaped lesion, the lesion primarily contains extracellular fluid. Caused by reduction in epithelial Cl- transport
Best’s Vitelliform macular degeneration
Transport of lactic acid from RPE
Requires a tight regulation of the intracellular pH
What transports nutrition from blood to photoreceptors?
RPE
Transports and RPE
Contains a lot of transporters to transport glucose to the photoreceptors
Things the RPE can transport into the photoreceptors
All-trans-retinol, glucose, DHA
Visual cycle
- reduction of all-trans-retinal into all-trans-retinol occurs in photoreceptors
- reisomerization of all-trans-retinol into 11-cis-retinal
- occurs in RPE
Where does reduction of all-trans-retinal happen
Photoreceptors
Here does reisomerixation of all-trans-retinol occur
RPE
Inherited retinal degeneration caused by mutations in genes of the visual cycle
Retinitis pigmentosa
Retinal degeneration caused by mutations int he genes of the visual cycle
Stargardt disease
The process of phagocytosis is under what control
Circadian
When is phagocytosis at its peak in the RPE
Morning
Every RPE cell is facing an average of ______ photoreceptors in the fovea
23
Inability of the RPE to phagocytosis photoreceptors outer segment
RP
What does RPE secrete into the photoreceptors
PEDF
VEGF
Other growth factors
Cytokines or immune modulators
VEGF in healthy eyes
Secreted in low concentrations
What is essential for maintenance of the structural integrity of retina?
Other factors (not PEDF or VEGF)
The most severe complication in age related macular degeneration. RPE cells secreted VEGF at a higher rate compared with RPE cells from eyes without neovasculariation
Choroidal neovascularisation
Retinal blood barrier
Retinal vascular endothelium
Tight junction between retinal pigment epithelium
Which option stand for apical side, basolateral side of RPE
Photoreceptor, choriocapillaris
Which option absorbs blue light
Lutein and zeaxanthin
Which one is driving force to remove water from apical side
Active transport of Cl- from retina to blood
Where does reisomerization of all-trans-retinol into 11-cis-retinal occur
RPE
Which disease is due to reduction of epithelia Cl- transport
Bests vitelliform macular degeneration
Which growth factor gets involved in choroidal neovascularization
VEGF
