Eye

Question 1

Parts of the Eye

Answer 1

Cornea: transparent epithelial tissue, no vasculature, doesn’t stain much
Sclera
Iris
Ciliary Bodies
Choroid: vascular coat
Lens: connects via ligaments
Retina

Question 2

Cornealscleral coat

Answer 2

Outer fibrous layer

Question 3

Corneoscleral limbus

Answer 3

Transition between white and clear

Question 4

Vascular coat

Answer 4

• Uvea (includes choroid, ciliary body, and iris)
• Iris: Highly pigmented with lots of smooth muscle

Question 5

Retina

Answer 5

• Inner layer (photopigments)
• Outer layer (pigmented epithelium)
• Ganglion

Question 6

Detailed eye structure

Answer 6

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Question 7

Cornea layers

Answer 7

1) Corneal epithelium: stratified squamous
2) Bowman’s membrane (anterior basement membrane) - fibrillar lamina, ends at corneoscleral limbus
3) Corneal stroma: Lamella containing collagen fibrils (specialized connective tissue)
- flat fibroblast-like cells + collagen lamellae (allows light to pass)
4) Descemets’s membrane: basement membrane (thinner) - contains pores
5) Corneal endothelium: Simple squamous; metabolic exchange for corneal cells occurs in this region
- diffusion of O2 + nutrients from aqueous humor (because no blood supply)

Question 8

Conjunctivitis (pink eye)

Answer 8

• viral infections
  symptoms:
• keratohyaline granules
• anucleate squamous cell
  exocytosis of lymphocytes
• spongiosis
• perivascular chronic inflammatory infiltrate

Question 9

Corneoscleral Junction

Answer 9

• More loose connective tissue (more vasculature) ??
• Sclera: thick fibrous layer containing flat collagen bundles - oriented in various directions - supports and protects the eye
• Stroma is less organized
• thicker

Question 10

Iridocorneal angle

Answer 10

• Merger of Iris, cornea, and sclera
• Stromal region: formation of trabecular meshwork which merge onto Canal of Schlemm
• Canals of Schlemm: drain the aqueous humor which is created by the ciliary bodies

Question 11

Iridocorneal angle and ciliary body

Answer 11

• Outer layer: smooth muscle, ciliary muscle (control shape of lens during accommodation?
• Inner layer: vascular region that extends into ciliary processes (LCT)
• Ciliary process: thickening inner vasculature, covered by pigmented ciliary epithelium (absorbs light)

Question 12

Ciliary Epithelium

Answer 12

• Works with aqueous humor
• Zonula fibers: forms suspensory ligaments that attach to lens (pulls/loosens lens for accommodation)

Question 13

Iris

Answer 13

• Connective tissue stroma - highly vascularized
• Posterior pigment epithelial cells - face the posterior chamber
• Anterior pigment myoepithelial cells: make up the dilator pupillae muscles
• Spincter pupillae muscles: circular

Question 14

Optic disc and nerve

Answer 14

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Question 15

Choroid strucutre

Answer 15

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Question 16

Retina Cells function

Answer 16

• Photoreceptors: rods and cones
• Bipolar neurons: conducting cells
• Associated neurons: send info to optic nerve brain
• Supporting cells (Muller’s cells)
• Retinal pigment epithelial cells: cuboidal cells near outside of eye (non-neuronal)

Question 17

Layers of retina

Answer 17

Light coming in
- inner limiting membrane
- nerve fiber layer
- ganglion cells
- inner plexiform layer
- inner nuclear layer
- outer plexiform layer
- outer nuclear layer
- outer limiting membrane
- layer of rod and cones
- retinal pigment epithelium
- lamina vitrea (Bruch’s membrane)
- choroid

Question 18

Retinal pigment epithelium

Answer 18

• A single layer of cuboidal cells which sit on basement membrane
  Function:
• absorbs light passing through neural retina - prevents reflection/glare
• isolates the retina from blood-borne substance - blood-retina barrier
• Maintains the photopigment integrity
• Phagocytoses and removes discs from rods and cones