POSTERIOR SEGMENT - Neurosensory Retina

Question 1

What is the structure of rod cones from RPE to vitreous?

Answer 1

Outer segment (transductive) –> inner segment (region for maintenance of cellular homeostasis) –> nuclear region (outer nuclear layers) –> transmissive region (outer plexiform/synaptic layer)

Question 2

Which types of cells are present in the inner nuclear layer? (3)

Answer 2

(1) bipolar neurons
(2) horizontal cells
(3) amacrine cells

Question 3

What is the difference between the outer segments of rods and cones ? (2)

Answer 3

RODS: cylindrical and contain rhodopsin pigment, made up of vitamin A (night blindness)

CONES: conical and contain iodopsin pigment (colour blindness)

Question 4

What is the difference in numbers between rods and cones?

Answer 4

rods: 120 million
cones: 5 million

Question 5

what is the maximum spectral sensitivity of the rod cells?

Answer 5

496nm

Question 6

What are the main differences between rods and cones? (4)

Answer 6

1. Rod discs are enclosed with a cell membrane
2. Rod concentration higher in periphery
3. Ratio of rod:cone is 20:1
4. Peak sensitivity of rods is 496nm, cones is 420 (S), 530 (M) and 560 (L)