Histology of the Eye Flashcards
Eye 3 layers Outer to Inner
Tunica Fibrosa (sclera, cornea)
Uvea (choroid {vascular}, ciliary body, Iris)
Retina (neural, non-neural)
When light hits the eye, whats the order it goes thru
- Cornea
- Anterior Chamber
- Posterior Chamber (behind the eye)
- Vitrious Chamber
- ***KNOW STRUCTURE OF EYE
Insects/ Arthropods have what kind of eyes?
Compound Eye- can see motion and shading but can’t focus
Tunica Fibrosa structures
Sclera: connective tissue that holds the eye in shape
Cornea: is composed of 5 layers— Corneal Epithelium (more outward touching air), Bowman’s Membrane (extracellular material), Stroma (thrickest layer), Descemet’s Membrane, Endothelium (close to anterior chamber)
Canal of Schlemm (at junction of sclera and cornea
Facilitates equilibrium of pressure in the eye by allowing fluid (when theres too much) from anterior chamber flow out through this canal
Uvea consists of these 3 layers
- Choroid: layer of vascular connective tissue (blood vessels) and once it reaches the opening of eye, it forms the iris
- Ciliary Body:
- Iris:
What is the choriocapillary?
Layer of smaller blood vessels (sub component of Choroid)
Ciliary Body
Small structure containing muscle that can contract and change shape of lens for light accommodation
Ciliary Body Component
- Ciliary Muscle
- Ciliary Process: folds of epithelium attached to ciliary muscles- each process has zonulary fibers attached to the lens.
- Change of muscle changes the lens size
Ciliary Process layers
Double layer of low columnar epithelium. One pigmented (inner layer because of melanin granules) the other non-pigmented epithelium (outer layer)
Ciliary process continues and lines the back of (posterior) what structure…
the Iris
Layers of the Iris
Double layer of epithelium
What gives rise to eye color>
Double layer of epithelium in the back of Iris- the amount of pigment (melanin granules) in the pigmented epithelium
- Less pigment (blue)
- Intermediate Pigment (green)
- More pigment (brown)
- No pigment (Albino)- looks pink due to reflection of blood
Heterochromia Irdis
Difference in coloration can be complete herterochromia
-Part of one iris is a different color from its remainder and finally in central heterochromia there are spikes of different colors radiating from the pupil
Zonula Fibers
Oxytalin fibers (first component of elastic fibers) form a bridge between ciliary body processes and the lens
Retina Components
lines back of eyeball
- Neural
- Anterior Non-Neural: consists of double layer of cells with pigmented and non pigmented epithelia
Vitrious chamber
Largest chamber,
has a lot of polyromic acid in it (glycosalidic glycans whichcontain sugars that are hydrophobic)- hold water- viscous
Ora Serrata
Transition spot from neural retina (has a spot called the fovea which contains only cones) to non-neural retina (which is double layer of cells that line the ciliated body/process and the back of the iris)
-End of Photoreceptors continues as double layer of epithelium
Which part of the eye gives best visual accuity (sharpness)
Fovea
3 layers of Neural Retina
- Outer layer of rods and cones embedded in pigmented epithelium (receive photons of energy in form of light and can initiate stimulus)
- Intermediate layer of bipolar neurons- Support cells that forms connections with ganglion cells (one end connects with ganglion cell the other connected to rods/cones—one end conencted to bipollar neurons and the other to axons of cells??)
- Internal layer of ganglion cells- deepest layer
Where are rods and cones embedded?
Deepest layer of retina (pigmented epithelium) are the photoreceptors
What is most sensitive to light?
Rod Cells- only give black and shades of gray / white- NO COLOR- Rhodospin
What is Rhodopsin responisble for?
Shades of black and white
Color- variants of iodopin which gives perspection of color
Cone Cells
Other name for Fovea Centralis
Macula– area only has CONES NO Rods
Macula Degeneration
Lose central part of vision
Detached Retina
Condition in which the retina detaches from the choroid-disrupting vision
Central Artery of the Retina runs through…
The optic nerve
Optic Nerve
Blind Spot also showing the central artery- no rods or cones
What is the Non- Neural Retina lined by
Double layer of epithelium lines the ciliary body and posterior iris
Accessory Structures of the Eye
Lens, Eyelid & Conjuctiva, Lacrimal Apparatus
Lens Components
- Lens Capsule, proteoglycans, Type IV Collagen
- Lens Epithelium, simple suboidal to columnar
- Differentiating lens fibers contain crystallin proteins
- Mature Lens Fibers
Cateract- what is it and what the solution
Clouding of lens, TReated with surgey by removing the natural lens and replaceming with an intraocular lens implant
Eyelid Component (inner to outer)
- Conjunctiva (most inner)
- Tarsus Fibroelastic Plate
- Meibomian Gland (sebaceous)
- Orbicular Muscle
- Eyelashes (outer)
Conjuctiva Structure
Mucosa covering portion of Sclera continues as lining of internal eyelid, stratified columnar to stratifies squamous
Lacrimal Apparatus Produce…
Tears, they are tubuloalveoli acini, serous
Extramuscular Muscles
pull muscle to move around and focus
