31: Eye Anatomy

Question 1

Sclera histo

Answer 1

Dense regular CT with flat bundles of type I collagen, microvascular near outer surface

Question 2

Vascularization of cornea

Answer 2

Avascular

Question 3

Anterior and posterior limiting membranes of cornea: basement membranes of what?

Answer 3

Anterior membrane: basement membrane of epithelium

Posterior membrane: basement membrane of endothelium

Question 4

Choroid histo

Answer 4

Loose CT with melanocytes

Question 5

Function of black layer in choroid

Answer 5

Prevents light from entering eye except through pupil

Question 6

What does the retina develop from?

Answer 6

Optic cup

Question 7

Outer pigmented layer of retina: histo

Answer 7

Simple cuboidal or low columnar ep

Question 8

Five functions of the outer pigmented layer of the retina

Answer 8

1. Absorbs scattered light
2. Forms blood-retina barrier
3. Isomerizes all-trans-retinal to 11-cis retinal
4. Phagocytosis of photoreceptor waste and free radicals
5. Secretes ATP, polypeptide GFs, immunomodulatory factors

Question 9

Where inner neural layer of retina extends to anteriorly?

Answer 9

To the ora serrata, continues as cuboidal ep covering the ciliary body and posterior iris

Question 10

Fovea centralis

Answer 10

Highest concentration of cones, where visual acuity is sharpest

Question 11

What is absent from the fovea centralis?

Answer 11

Vessels, cell bodies, axons

Question 12

Where is the macula lutea

Answer 12

Surrounding fovea

Question 13

Macula lutea function

Answer 13

Protects cones; antioxidant properties with short-wave UV filter

Question 14

Where is the blind spot and why

Answer 14

Optic disc - it lacks photoreceptors and only has ganglionic cell axons

Question 15

What makes up the optic nerve

Answer 15

Retinal ganglion cell axons

Question 16

What happens as the optic nerve passes through sclera

Answer 16

Becomes myelinated