Retina

Question 1

Why is the optic disk a blind spot

Answer 1

Absence of photoreceptors

Question 2

Name the 11 retinal layers

Answer 2

ILM- Inner limiting membrane
NFL- Nerve Fibre layer
GCL- ganglion cell layer
IPL- inner plexiform layer
INL- inner nuclear layer
OPL- outer plexiform layer
ONL- outer nuclear layer
OLM- outer limiting membrane
is- (photoreceptors) inner segments
os- (photoreceptors) outer segments
RPE- retinal pigment epithelium

Question 3

Which of the photoreceptors has a higher number throughout most of the retina

Answer 3

Rods

Question 4

Which part of the retina contains no rods but many cones

Answer 4

Foveola

Question 5

What is the fovea

Answer 5

Area of the retina that provides the highest vision acuity
Center of gaze

Question 6

What is the neural retina

Answer 6

Innermost layer of the retina, which contains the photoreceptor cells

Question 7

What is the ILM

Answer 7

Inner limiting membrane- a transparent, delicate structure forming the interface between neural retina and vitreous humor

Question 8

Which are the components of NFL

Answer 8

Axons of ganglion cells

Question 9

What is the composition of GCL

Answer 9

Ganglion cell BODIES
some amacrine cell bodies

Question 10

Definition and function of ganglion cells

Answer 10

Final output neurons in the brain
Transmit visual information from the eye to the brain

Question 11

What is the primary function of IPL

Answer 11

Facilitates the communication between bipolar cells, amacrine cells and ganglion cells

Question 12

Describe the composition of the IPL

Answer 12

Axons and dendrites
Forms synapses of bipolar cells and amacrine cells WITH ganglion cells

Question 13

What are the 4 types of cell bodies found in the INL

Answer 13

bipolar
horizontal
Amacrine
Müller cells

Question 14

What is the composition of the OPL

Answer 14

Synapses of photoreceptor cells with bipolar and horizontal cells

Question 15

Are axons pre/post synaptic

Answer 15

Presynaptic

Question 16

Are dentrites pre/post synaptic

Answer 16

Post synaptic

Question 17

Which layer are the nuclei and cell bodies of rods and cones found

Answer 17

Outer Nuclear Layer

Question 18

Function of the photoreceptor inner segment

Answer 18

Responsible for metabolic and synthetic activities

Question 19

Function of the photoreceptors outer segment

Answer 19

Contains visual pigments responsible for light absorption

Question 20

Function of photoreceptor cilia

Answer 20

Facilitates communication and transport between inner and outer segments

Question 21

Describe the shape of the cells of RPE

Answer 21

Hexagonal
Simple cuboidal epithelium
Simple columnar epithelium over the fovea

Question 22

Function of RPE

Answer 22

forms barrier between choroidal blood and neural retina
Absorption of light by melanin
Synthesis of visual pigment chromophore

Question 23

What pigment is found in RPE and what is its function

Answer 23

Melanin
Absorbed excess lightband reduces light scattering in the eye

Question 24

Advantage of the macular pigment absorbing blue light

Answer 24

Minimizes chromatic aberration- results in a sharper image
Reduce the amount of high energy blue light reaching the sensitive cells of retina

Question 25

Describe the differences between the blood supply of outer retina and the inner retina

Answer 25

Outer retina- choroidal blood Inner retina- blood from blood vessels originating at the optic disk

Question 26

Based on adhesion and cell types, what are the two types of retina

Answer 26

Neural (neurosensory) retina Retinal pigment epithelium RPE

Question 27

What makes up the outer retina

Answer 27

Photoreceptors and RPE

Question 28

Two main functions of Bruch’s membrane

Answer 28

separating retina and choroid gaseous, nutrients and waste product exchange

Question 29

Where is Bruch’s membrane located

Answer 29

Between RPE and choroid

Question 30

What are the different functions of the apical and basal surfaces of RPE

Answer 30

Apical- phagocytosis of shed outer segments of photoreceptors Basal- facilitates substance exchange between choroid and retina

Question 31

Describe how the surface areas of the apical and basal surfaces is increased

Answer 31

Apical- microvilli Basal- infoldings

Question 32

Why is the RPE essential for viability and function of photoreceptors (7reasons)

Answer 32

1. Transport of nutrients, oxgyen etc between choroid and RPE 2. Storage of nutrients 3. Transport of nutrients to photoreceptors 4. Tight junctions regulate water and molecule flow 5. Phagocytosis of shed outer segments 6. Recycling of nutrients from phagocytosed os 7. Removal of waste

Question 33

What nutrients are recycled from phagocytosed os

Answer 33

Lipids Proteins Vitamin A

Question 34

3 Functions of omega-3 lipids

Answer 34

Photoreceptor function especially in the os Anti-inflammatory properties Protection against oxidative stress due to high metabolic stress in photoreceptors

Question 35

Why does the macula appear darker on a fundus

Answer 35

Increased concentration of melanin in the RPE

Question 36

What is the maximal retinal thickness range

Answer 36

349+/- 17 micrometers