Flashcards in Retina and Vitreous Vol. 2 Deck (38)
What type of photoreceptor makes a one-to-one synapse on bipolar cells?
What type of photoreceptor is associated with making multiple synpases on a single bipolar cell?
What creates the internal limiting membrana (ILM)?
Footplates of Muller calls
What creates the external limiting membrana (ELM)?
Zonular attachments between photoreceptors and Muller cells
What creates the appearance of the middle limiting membrane?
Synaptic connection between the photoreceptors and the bipolar cells
Where are the two layers of capillaries of the retina located?
1. Ganglion cell layer/NFL 2. Inner nuclear layer
How is oxygen tension of the outer retina related to amount of light?
Oxygen tension of the outer retina decreases with dark (e.g. approaching zero)
What percentage of the oxygen used in the fundus is provided by the retinal vascular system?
Approx.5% (the rest provided by the choroid)
What is the embryologic origin of the RPE?
What does the RPE become continous with at the ora serrata?
Pigmented epithelial layer of the ciliary body
Where is the apical layer of the RPE located?
On the side of the photoreceptors
How does the shape of RPE cells change in the macula?
RPE cells become taller and denser in the macula
What structures connect the RPE cells together at the apical surface?
What structures form the outer retinal blood-ocular barrier?
What is the function of melanosomes of the RPE?
Absorption of light
What color of light is the most absorbed by the RPE?
What accounts for the fact that the RPE absorbs blue light better than red light?
Rayleigh absorption (e.g. shorter wavelength)
At what time of the day do rods shed their outer segments?
At what time of the day do cones shed their outer segments?
What does A2E form in the RPE?
Where does most of the regeneration of 11-cis? ratinaldehyde from 11-trans? retinaldehyde occur?
What causes the bone spicule appearance of retinitis pigmentosa?
Hyperplasia of RPE cells that envelope the retinal vessels
Patient with RPE abnormalities and intestinal polyposis
Think Gardner syndrome
Name the 5 layers of Bruch's membrane.
1. Basement membrane of the RPE 2.Collagen 3.Elastic fibers 4.Collagen 5.Basement membrane of the choriocapillaris
What condition is associated with increased fragility of Bruchs' membrane?
Through what vessels does blood enter the choroid?
Short posterior ciliary arteries
What is the outer layer of choroidal vessels known as?
What layer of the choroid does the Haller layer merge with?
Where is the choroid the thinnest?
Ora serrata (0.1 mm)