Term
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Definition
frontal, lacrimal, maxillary, zygomatic
humans have a complete 360* of orbital bones. K9 and fel are missing a portion so are more prone to ext trauma |
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Term
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Definition
optic, orbital, alar
cranial fissure will have lots of cranial nn |
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Term
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Definition
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Term
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Definition
rectus and retrobulbar
rectus will do upside down movements |
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Term
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Definition
maxillary (source of blood to eye, if you hit it =death),
opthalmic,
ciliary |
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Term
| lacrimal glands of the eye |
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Definition
DORSAL LACRIMAL GLAND
*produces majority of the aq portion of tear film, 60-70%
LACRIMAL GLAND OF 3RD EYELID
* produces 40% of aq
all w/in orbit to keep eye lubricated |
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Term
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Definition
mammals blink with upper eye lid
birds and reptiles blink w/ lower eye lid
CANTHUS- where the eyelids meet, could be medial or lateral |
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Term
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Definition
outer epidermis w/ multp capillaries to protect eye
upper and lower portions contain:
◦ Meibomian glands
◦ Cilia
◦ Conjunctiva (no hairs)
form musculocutaneous junc --> skin on one side, mucous memb on other. very thin memb lined w/ epithelium and can slide back and forth across top off eyeball |
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Term
| eyelid closure/opening controlled by |
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Definition
CLOSURE (usually involuntary)
◦ Obicularis
◦ CN VII
OPENING (to allow light photons in)
◦ Levator palpebral superioris
◦ CN III |
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Term
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Definition
nuerous on upper and loweer eyelid
EX: styes are impactions of meibomian (lipid inside impacted = meibom)
meibom- oil that sits on top of tear film, prevents tears from evaporating |
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Term
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Definition
◦ protect cornea
◦ blink reflex allows tear film to distribute all over cornea
- flush potential fb/noxious molecules
◦ produce meibom from meibomian glands
◦ lined by palpebral conjunctiva w/ goblet cells (produce mucin) |
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Term
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Definition
◦ cartilage
◦ lacrimal gland
◦ lymphoid nodules
◦ conjunctiva
most species have. cart aligned w/ conjunctiva on both sides. has immune syst nodules that get activated in presence of dust, allergens, smoke |
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Term
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Definition
◦ Protects cornea as a conjunctival lined membrane with cartilage
- Passive movement of membrane due to retraction of globe
◦ Local immune system: lymphoid nodules
◦ Produces 40% aqueous portion of tear film
*if you puch on eyeball you can prolapse third eyelid
* retrobulbar musc (activated by CN VI) will prolapse 3rd eyeliid to protect eye (cant really see this happen) |
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Term
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Definition
Tear film composition
A) Meibum: lipids from meibomian gland
B) Aqueous: water from lacrimal glands
C) Mucin: glycoproteins from conjunctival goblet cells |
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Term
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Definition
Trilaminar fluid that covers cornea and conjunctiva
A) Meibum: prevents evaporation
B) Aqueous: contributes nutrients, immunoglobulins, WBC
C) Mucin: promotes adherence to cornea and conjunctiva
◦ Physically protects cornea and conjunctiva
◦ dilutes topical meds
◦ Exits via nasolacrimal system
- pumps drain excess tears into nose (why you have a runny nose when you cry) |
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Term
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Definition
◦ Lacrimal puncta (upper and lower)
- K9, fel, horse have 2 that join a duct and empty into nose; pig only have 1
◦ Canaliculi (2)
◦ Duct
◦ Nasal punctum |
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Term
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Definition
Thin translucent mucous membrane that reflects on itself; lining of the underside of the eyelid
◦ Protects the sclera
◦ Epithelial border: continuous with corneal epithelium
- so what is under the eyelid will reflect back onto the eyeball
◦ Contains capillaries that are normally invisible
◦ Goblet cells produce mucin
when healthy = thin and transparent
when infected = looks very angry, erethmyous |
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Term
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Definition
o White disorganized collagen fibers
o Covered by bulbar conjunctiva
o Perforations: optic nerve, blood vessels
o site where musc attach
NOTE: when removing the eye, you want to cut the musc insertion right at the sclera to limit blood loss |
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Term
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Definition
White protective fibrous outer tunic of eye
◦Young: elastic
◦Adult: fibrous
Provides entry for ocular vasculature and optic nerve
Serves as site for extraocular muscle attachments
◦CN III: dorsal, medial, ventral, and ventral oblique recti
◦CN IV: dorsal oblique rectus
◦CN VI: lateral rectus and retrobulbar muscle cone |
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Term
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Definition
back part of the eye is where the key structures are. think of a balloon filled w/ water.
trauma causes sclera to squish and E causes it to snap back and break |
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Term
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Definition
Borders:
◦ Tear film
◦ Limbus
-where cornea becomes disorganized and more sclera
◦ Aqueous humour
3 layers:
◦ Epithelium
◦ Stroma
◦ Endothelium (inside eye)
◦ Descemet’s membrane
**very organized collagen fibers
Innervation: ophthalmic branch of CN V (Blink reflex) |
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Term
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Definition
o Non-keratinized stratified epithelium
-no bv, keratin, lymph
o Lipophilic layer
o Renews itself in 7 days
o Mechanical barrier
o transparent structure
- lets light photons penetrate eye
- cannot be pigmented or we cant see
- to stay transparent, receives nutrients from tears as opposed to vasculature |
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Term
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Definition
o Parallel collagen fiber bundles made from keratocytes
-precisely aligned collagen allow to let light in
-epithelium (top) and endothelium (bottom) to protect
- if you remove epithelium, then stroma would absorb tear film
o Hydrophilic in nature
o Retains fluorescein stain
o CN5 sensory ending
- cornea is innervated by this n so very sensitive area and can be distressing |
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Term
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Definition
◦ Monolayer
◦ No mitosis
◦ Makes Descemet’s membrane
*back of cornea facing iris
* keeps cornea dehydrated b/c dont want fluid in there. has memb to help |
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Term
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Definition
◦ Basement membrane
◦ Elastic in nature
◦ Does not retain dye
◦ Barrier |
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Term
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Definition
Epithelium: protects cornea due to tight junctions
Transparent: no keratin, pigmentation, vascularisation
7 day turnover, 10 replicative cycles, germinal cells at limbus
- heals quickly
Stroma: precise orientation of collagen fibrils leads to transparency
Transparent: no vascularisation or lymphatics
24 hour delay in healing abilities
- try to delay scarring so everything can arrange appropriately (better vision) b4 it happens
Endothelium: maintains dehydrated and transparent status of cornea
Na/K pump keeps aqueous out of stroma |
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Term
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Definition
o Iris: central opening is pupil
o Ciliary body: aqueous humour production
o Choroid: supplies nutrients to retina |
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Term
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Definition
o pupil gets small in light b/c many light photons are hitting back of eye so it dec SA to limit exposure.
o in opposite, eye will dilate to inc SA and grab more light photons to see better
sphincter musc will shirnk pupil (to a slit= fel, pinpoint =K9) other musc will allow eye to open up pupil |
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Term
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Definition
◦ Opaque colourful structure
◦ Door monitor of light photons
◦ Bright lights: pupil constricts to limit potentially damaging photons
◦ Low lights: pupil dilates to get as many photons into eye
◦ Full of blood vessels: endothelial cells have tight junctions
- limit bacteria
◦ Anterior face: no tight junctions: leaks “stuff” into anterior chamber |
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Term
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Definition
vertical iris --> only in domestic cats (big ccats do not have a slit)
ungulates will have slit iris (prey lifestyle) to allow them to have a lrger FOV |
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Term
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Definition
Production of aqueous humour (never overproduces)
From nonpigmented ciliary body epithelium
Static or decreased production possible
Provides accommodation: muscle action on zonules (ligaments that hold onto lens)
Near vision: contraction of muscles (ciliary body) leads to relaxation of zonules, spherical lens
Far vision: relaxation of muscles leads to tension on zonules, discoid lens |
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Term
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Definition
Nourishes the retina (photoreceptors)
- retina is hungry all the time, so choroid is working to feed it/ supply nutrients
No tight junction or auto-regulation of blood vessels |
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Term
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Definition
o Capsule
o Suture lines
o Equator |
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Term
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Definition
Clear structure due to precise orientation of lens fibers
- magnifies things
Permits accommodation (focusing)
-Action on zonules for near and far vision
Lifelong production of lens fibers:
-Compression in center: nuclear sclerosis
Malalignment of lens fibers: cataract
-has a capsule w/ very precisely alignede lens fibers = no opacity, see well. when not aligned = cataracts, opacity
- catract sx --> empty out lens fiber b/c they are misaligned |
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Term
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Definition
o Anterior
◦ Water
◦ produced by ciliary body
o Posterior
◦ aq humor
◦ nourishing Around lens, back of cornea, little of eyelids
o Vitreal
◦ Viscous type of fluid
from front of eye (more watery fluid) to back (more viscous) |
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Term
| anterior and posterior chambers |
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Definition
Contain aqueous humour: clear fluid
Nourishes: cornea, iris, lens
Made by: non-pigmented ciliary body epithelium
Travels from posterior to anterior chamber via pupil
Exits by iridocorneal angle
-Secondary exit: uveoscleral outflow
-Fast turnover rate: 24 hours |
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Term
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Definition
not big in cats, more in K9 and horses
acts as another escape route that couls be activated to help. good target for drugs |
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Term
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Definition
where vitreous meets iris
kind of like the drain of the eye
if not formed properly --> can block and aq keeps accumulating --> glaucoma (blind and painful) tx w/ sx or eye drops |
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Term
| anterior and posterior chamber func |
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Definition
Blood aqueous barrier: prevents infection
- Tight junctions: non-pigmented ciliary body epithelium & iris endothelial cells
- Protection: prevents contamination inside eye
No barrier between all chambers |
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Term
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Definition
Transparent gel that permits light to reach retina
-denser consistency allows appose retina to the back of the eye (retina anchored at optic n + at periphery, rest of it is opposed)
-exerts press on retina to maintain position on choroid to get nutrition
Maintains shape of eye
Maintains retinal apposition to choroid
Nourishes inner retina
Slow turnover rate (months)
- if you put a drug in vitreous, usually slower pace and can last up to 3m |
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Term
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Definition
if vitreous becomes more liquid, will not exert as much press on retina so it will come off and have no connection to nutrition --> retinal detachments (not painful, but you see black)
majority of retina is not anchored so if you re-anchor you can get vision back |
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Term
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Definition
9 layers + retinal pigment epithelium
* not teaching us the others, but bottom layer is retinal epithelium
*retina does not actual havee color,depnds on color coat of animal |
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Term
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Definition
Serves as the flash card in a camera
-Photoreceptors start the process of making an image (antennae)
-Signal is modified by several retinal layers
-Signal is delivered to ganglion cells and their axons (fiber optic cable)
Mainly apposed to choroid and only anchored in periphery and at optic nerve
-Can easily detach with choroidal effusion or vitreal disease
Dorsal retina has adjacent tapetum
-Tapetum serves to re-stimulate photoreceptors |
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Term
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Definition
K9 and fel dont have as many antennae and ganglion cells as humnas --> these animals have more pixelated view of world.
- the more ganglion cells, the less pixelated
# and type of photoreceptors is species specific |
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Term
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Definition
great horned owl
* have more rods b/c need to see in low light/ quick movemetns
parrot
* have more retina to see more color (fruits) |
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Term
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Definition
serves as a mirror so when one light photon come through, it bounces off tapetum and restimulates photoreceptors so giving twice as much info for cats that it will for humans (humans dont have tapetum)
in cats, tapetum is much more more active than in K9, so cats can see better than K9 |
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Term
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Definition
* links eyeball to brain
* a very sepcialized/unique cranial n
-only one w/ dura mater and CSF (reason why it is so involved w/ the brain)
* perforates back of the eye (could be a weakness)
o CN II
o Axons from ganglion cells
o Dura matter & CSF |
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Term
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Definition
Fiber optic cable that delivers image to visual cortex
- Made of ganglion cell axons
Covered by dura matter and CSF
- Directly communicates with CNS
info travels from ganglion cells --> down to optic n --> brain |
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