Retinal Histology

Question 1

Ora serrata

Answer 1

anterior, non-sensory retinal pigmented epithelium located just posterior to the cilliary body

can lance with needle w/o damage to vision

Question 2

Macula Lutea

Answer 2

area around the fovea
high density of cones

vessels form thin loops at the periphery

center=fovea

Question 3

Optic disc

Answer 3

where the optic n. and vessels enter the eye

no photoreceptors, bipolar cells, or ganglion cells. only unmyelinated axon

Question 4

layers of the retina

Answer 4

from exterior (posterior) to interior (anterior)

1) Pigmented epithelial cells
2) photoreceptors
3) outer limiting membrane
4) outer nuclear layer
5) outer plexiform layer
6) inner plexiform layer
7) ganglion cell layer
9) optic n. fibers
10) inner limiting membrane

Question 5

Interphotoreceptor matrix

Answer 5

connection bw the photoreceptor and RPE

important for recycling of older discs and transports retinol to RPE and retinal to photoreceptors via interstitial retinoid binding protein

contains melanin which absorbs light and prevents it from being reflected back into eye

Question 6

Retinal pigmented epithelium

Answer 6

contain melanin granules
phagocytose and shed discs (in lysosomes) released into choriocapillaries

converts retinol to retinal

Question 7

photopsin

Answer 7

the opsin protein that is in cones

with chromophore 11-cis retinAL it is caled iodopsins

Question 8

bleaching

Answer 8

photopigment can absorb a photon of light and change conformation

i.e. changes retinol into retinal 
allows photopigment to acts as GPCR
converts cGMP to GMP
closes cGMP sensitive Na channes to close 
hyperpoloarizes cell 
decreased NT release

Question 9

Rhodopsin

Answer 9

photopigment present in the discs

contains 1) Opsin 2) retinal

which opsin is present determines wavelength absorbed

called photopsin in cones

Question 10

Leber congenital amaurosis type 2

Answer 10

mutations in the RPE65

prevents you from isomerizing trans to cis in the RPE retinal

Question 11

bipolar cell

Answer 11

receive impulse from photoreceptor cell

diffuse cone BP and rod BP get input from multiple photoreceptors and synapse on multiple gnaglion cells

midget cone bipolar get info from one cone and synapse on one ganglion cell

Question 12

ganglion cells

Answer 12

dendrites in the inner plexiform layer

diffuse ganglion cells contact several BP cells

Midgit ganglion contact one BP

Question 13

association neurons

Answer 13

integrate signaling

amacrine cells and horizontal cells

Question 14

amacrine cells

Answer 14

neuites ending axon terminals of BP cells and ganglion cell dendrites and bodies

Question 15

horizontal cells

Answer 15

neurites ending on cone pedicles and rod spherules

Question 16

Glial cells

Answer 16

mueller cells and microglia

Question 17

fovea

Answer 17

on visual axis of cornea
depression of retina, flatteing of inner layer to let more light in

highest density of cones which means high visual acuity

poor low light

Question 18

fovea centrais

Answer 18

highly packed cones arranged at an angle to pigmented layer

outer nuclear layer of the retinal do no obstruct light pathway

Question 19

optic n.

Answer 19

convergence of axons of retinal ganglion cells

unmyelinated affarents, myelination begins at disc (area of no photoreceptors)

Question 20

central retinal a

Answer 20

provides blood to inner parts of retina

branches run posterior to the inner limiting membrane

Question 21

Retinal detachment

Answer 21

detachment of the photoreceptors from the RPE

lack of nutrients cause retinal cells to die

Question 22

preproliferative Diabetic retinopathy

Answer 22

nonproliferative

increased size and number of intraretinal hemorrhages, but limited vision loss

much of vision loss occurs due to macular edema

Question 23

Age related macular degneration

Answer 23

when photoreceptors and RPE break down (can be due to Drusen) (dry) or when abnormal blood vessels grow and leak under the macula (wet)

causes rapid and painless vision loss

Question 24

Proliferative Diabetic retinopathy

Answer 24

formation of new blood vessels

can protrude into the vitreous and cloud vision and detach retina

may even extend into more anterior structures

Question 25

Diabetic retinopathy

Answer 25

microaneurisms (outpouching of retinal capillaries)

cotton wool spots (ischemia) 
dilated retinal veins 
lack of perfusion of retinal aa. 
loss of pericytes
apoptosis of capillary endothelial cells 

Hyperglycemia-induced intramural pericyte death and thickening of the basement membrane lead to incompetence of the vascular walls