Retina and Vitreous Vol. 2

Question 1

What type of photoreceptor makes a one-to-one synapse on bipolar cells?

Answer 1

Cones

Question 2

What type of photoreceptor is associated with making multiple synpases on a single bipolar cell?

Answer 2

Rods

Question 3

What creates the internal limiting membrana (ILM)?

Answer 3

Footplates of Muller calls

Question 4

What creates the external limiting membrana (ELM)?

Answer 4

Zonular attachments between photoreceptors and Muller cells

Question 5

What creates the appearance of the middle limiting membrane?

Answer 5

Synaptic connection between the photoreceptors and the bipolar cells

Question 6

Where are the two layers of capillaries of the retina located?

Answer 6

1. Ganglion cell layer/NFL 2. Inner nuclear layer

Question 7

How is oxygen tension of the outer retina related to amount of light?

Answer 7

Oxygen tension of the outer retina decreases with dark (e.g. approaching zero)

Question 8

What percentage of the oxygen used in the fundus is provided by the retinal vascular system?

Answer 8

Approx.5% (the rest provided by the choroid)

Question 9

What is the embryologic origin of the RPE?

Answer 9

Neuroectoderm

Question 10

What does the RPE become continous with at the ora serrata?

Answer 10

Pigmented epithelial layer of the ciliary body

Question 11

Where is the apical layer of the RPE located?

Answer 11

On the side of the photoreceptors

Question 12

How does the shape of RPE cells change in the macula?

Answer 12

RPE cells become taller and denser in the macula

Question 13

What structures connect the RPE cells together at the apical surface?

Answer 13

Zonulae occludentes

Question 14

What structures form the outer retinal blood-ocular barrier?

Answer 14

Zonulae occludentes

Question 15

What is the function of melanosomes of the RPE?

Answer 15

Absorption of light

Question 16

What color of light is the most absorbed by the RPE?

Answer 16

Blue light

Question 17

What accounts for the fact that the RPE absorbs blue light better than red light?

Answer 17

Rayleigh absorption (e.g. shorter wavelength)

Question 18

At what time of the day do rods shed their outer segments?

Answer 18

Dawn

Question 19

At what time of the day do cones shed their outer segments?

Answer 19

Dusk

Question 20

What does A2E form in the RPE?

Answer 20

Lipofuscin

Question 21

Where does most of the regeneration of 11-cis? ratinaldehyde from 11-trans? retinaldehyde occur?

Answer 21

RPE

Question 22

What causes the bone spicule appearance of retinitis pigmentosa?

Answer 22

Hyperplasia of RPE cells that envelope the retinal vessels

Question 23

Patient with RPE abnormalities and intestinal polyposis

Answer 23

Think Gardner syndrome

Question 24

Name the 5 layers of Bruch’s membrane.

Answer 24

1. Basement membrane of the RPE 2.Collagen 3.Elastic fibers 4.Collagen 5.Basement membrane of the choriocapillaris

Question 25

What condition is associated with increased fragility of Bruchs' membrane?

Answer 25

Pseudoxanthoma elasticum

Question 26

Through what vessels does blood enter the choroid?

Answer 26

Short posterior ciliary arteries

Question 27

What is the outer layer of choroidal vessels known as?

Answer 27

Hailer layer

Question 28

What layer of the choroid does the Haller layer merge with?

Answer 28

Sattler layer

Question 29

Where is the choroid the thinnest?

Answer 29

Ora serrata (0.1 mm)

Question 30

What is the maximal thickness of the choroid at the posterior pole?

Answer 30

0.22 mm

Question 31

Where do the capillaries of the choroid drain into venules?

Answer 31

Choriocapillaris

Question 32

What has the highest blood flow rate of any tissue in the body?

Answer 32

Choroid

Question 33

What cells are the exposed to the highest oxygen tension that any other part of the body?

Answer 33

RPE cells {e.g. increases risk of oxidative damage)

Question 34

What is the most common intraocular tumor in adults?

Answer 34

Melanoma

Question 35

How many vortex veins does the each eye contain?

Answer 35

4 or 5

Question 36

What condition is associated with small eye with excessively thickened sclera?

Answer 36

Nanopthalmos

Question 37

What complication can be caused by the thickened sclera of nanophthalmos?

Answer 37

Uveal effusion syndrome (eg.due to impaired passage of fluid through the sclera)

Question 38

What structures mark the equator of the globe?

Answer 38

Vortex veins