Eye Flashcards
Week 5
Parts of the Eye
Cornea: transparent epithelial tissue, no vasculature, doesn’t stain much
Sclera
Iris
Ciliary Bodies
Choroid: vascular coat
Lens: connects via ligaments
Retina
Cornealscleral coat
Outer fibrous layer
Corneoscleral limbus
Transition between white and clear
Vascular coat
- Uvea (includes choroid, ciliary body, and iris)
- Iris: Highly pigmented with lots of smooth muscle
Retina
- Inner layer (photopigments)
- Outer layer (pigmented epithelium)
- Ganglion
Detailed eye structure
…
Cornea layers
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)
Conjunctivitis (pink eye)
- viral infections
symptoms: - keratohyaline granules
- anucleate squamous cell
exocytosis of lymphocytes - spongiosis
- perivascular chronic inflammatory infiltrate
Corneoscleral Junction
- 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
Iridocorneal angle
- 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
Iridocorneal angle and ciliary body
- 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)
Ciliary Epithelium
- Works with aqueous humor
- Zonula fibers: forms suspensory ligaments that attach to lens (pulls/loosens lens for accommodation)
Iris
- 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
Optic disc and nerve
…
Choroid strucutre
…
Retina Cells function
- 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)
Layers of retina
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
Retinal pigment epithelium
- 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
