LEC 3 retinal histology B7

Question 1

LIght energy is transformed into a neural signal

Answer 1

phototransduction

Question 2

Outer segment of rod photoreceptor is adjacent to what?

Answer 2

RPE

Question 3

Discs are composed of lipids which is the photopigment of the rod… what is it?

Answer 3

Rhodopsin

Question 4

WHat is the APEX to APEX relationship? (KNOW IT IMPORTANT)

Answer 4

APEX of RPE and APEX of Photoreceptor outer segments

Question 5

THis is the photopigment of the rod (only in rod)

-Located in the membrane of the discs (90%) and to a lesser extent in the cell membrane around the cell body (10%)

Answer 5

Rhodopsin

Question 6

Rhodopsin has peak absorption of light at wavelengths of ~_____?

Answer 6

500 nm

Question 7

Rod outer segments ______ are shed daily in the early morning. SHed into what space as what? (important concept)

Answer 7

Discs

Shed into Bruch’s membrane as Drusen

Question 8

Over 100 mutations in the rhodopsin gene have been identified that can lead to inheritance of the rod photoreceptor dystrophy called what?

Answer 8

Retinitis pigmentosa (RP)

Question 9

Retinal vessels supply what?

Choroid supplies what?

Answer 9

inner retina

outer retina

Question 10

What is the connecting bridge between outer and inner segment?

Answer 10

Cilium

Question 11

If cilium doesn’t form properly what happens?

Answer 11

Cant get protein for rhodopsin into the inner segment (can lead to blindness)

Question 12

Mitochondria are contained in what?

Answer 12

Ellipsoid (is closer to the rod outer segment)

Question 13

________ region is closer to the cell body of the rod.

Answer 13

Myoid - contains metabolic machinery for synthesizing new discs

Question 14

The ____________ extends from the inner segment to the cell body

Answer 14

rod outer fiber

Question 15

The outermost layer is composed of _______

Answer 15

cones

Question 16

Rod cell bodies are in what layer?

Answer 16

Outer nuclear layer

Question 17

The synaptic terminal of a rod is called what?

Answer 17

Spherule

-Each spherule has one triad

Question 18

WHat extends further into the retina than the Rod spherule?

Answer 18

Cone pedicles (slide 25 picture)

Question 19

How many rod photoreceptors are there?

Answer 19

92-120 million
SCOTOPIC
NO RODS IN FOVEA
ALL RODS CONTAIN RHODOPSIN

Question 20

What are the 3 opsins, what wavelength do they peak at, and what percent are they seen with? (IMPORTANT)

Answer 20

SHort- Blue- 488 nm (10%)
Middle- Green- 531 nm (60%)
Long- Red- 588nm (30%)

Question 21

____________ is when one of the three cone photopigments is absent and color is reduced to two dimensions

Answer 21

Dichromacy

Question 22

Dichromats are categorized into 3 different types, what are they?

Answer 22

Protanopes (absence of L cones)
Deuteranopes (loss of M cones)
Tritanopes (loss of S cones)

Question 23

Cone cell bodies are a _________ of nuclei in the outermost row of the ______.

Answer 23

Monolayer

Outer nuclear layer

Question 24

WHat is the neurotransmitter released by cone photoreceptors?

Answer 24

Glutamate

Question 25

How many cone photoreceptors are in the retina?

Answer 25

5 to 6 mill | 10% in the fovea

Question 26

These modulate the signal from photoreceptors to bipolar cells -They provide inhibitory feedback to photoreceptors and inhibitory feed-forward to bipolar cells.

Answer 26

Horizontal cells

Question 27

Where are horizontal cells found? (IMPORTANT) | WHat neurotransmitter do they use?

Answer 27

Outer most row of Inner nuclear layer | GABA- inhibitory

Question 28

What is the second neuron in the chain between the photoreceptors and the retinal ganglion cells.

Answer 28

Retinal bipolar cells

Question 29

What are the 2 types of bipolar cells?

Answer 29

Rod bipolar cells | Cone bipolar cells

Question 30

COne bipolar cells are established into ___ or ___ cells.

Answer 30

ON bipolar cells or OFF bipolar cells | rods are always on

Question 31

The most widely studied amacrine cell in the retina is the narrow-field ___________ cels.

Answer 31

A2 amacrine

Question 32

These convey the rod signal to the retinal ganglion cells as rod photoreceptors that have no direct contact with reinal ganglion cells.

Answer 32

A2 amacrine cellls

Question 33

Rod bipolar cells do not directly connect with what? they have to use what to connect them? (important)

Answer 33

retinal ganclion cells | A2 amacrine cells

Question 34

What are the radial glial cells of the retina? Creep around everything. Nuclei are located in what?

Answer 34

Muller cells | Inner nuclear layer

Question 35

These cells are found in the RNFL and the RGCL. Star shaped and send out processed that surround and provide structural support to the vasculature and axons located in the RNFL.

Answer 35

Astrocytes

Question 36

These are found in small number in the RNFL. Mobile phagocytes that become highly active and can be found anywhere in the retina under pathological conditions (e.g. trauma injury)

Answer 36

Microglia