Q8 - Retina, Anatomy & Physiology

Question 1

Layers of Retina

Answer 1

(From outside->inward)

1. Int. Limiting membrane
2. Nerve fiber layer (ganglion cell axons)
3. Ganglion cell layer
4. Inner plexiform layer (synapses 2nd&3rd neurons)
5. Inner nuclear layer (bipolar cells)
6. Outer plexiform layer (synapses 1st&2nd neuron)
7. Outer nuclear layer (Rods&Cones nuclei)
8. Outer limiting membrane
9. Rods & Cones layer (actual photoreceptors)
10. Retinal Pigmented Epithelium
11. Bruch’s membrane (BM of the choroid).

Question 2

Macula lutea

Answer 2

• contains only cones &RPE. Central vision, fovea. It’s own nerve supply, nutrition only from underlying choroid.

Question 3

Optic disc

Answer 3

Entry/Exit point of ganglion nerve/optic nerve. Has central retinal artery&vein.

Question 4

Vascular supply of retina

Answer 4

2 circulations of the ophthalmic artery (sup & inf)

Question 5

Physiology

Answer 5

Registers wavelengths between 380-760nm.
110-125 million rods -> mesotopic (twilight) and scotopic (night) vision. Rhodopsin.
6-7 million cones -> in macula, for color, phototopic (daytime) and resolution. Blue, green and red. Iodopsin.