ocular anatomy and physio nbeo1.txt
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What is phthiriasis palpebrarum?
What happens in the cornea as it ages?
- Intercellular junction construction
- Decreased wound healing
- Spatial degradation
- Corneal opacities
- Corneal sensitivity
- Corneal curvature in vertical meridian (ATR)
- Corneal thickness
- Increase light scatter
- Thickening of descemet's membrane
- Thinning of endothelium
What is Hudson-stahli line?
Horizontal pigment line
What are Krukenberg spindles?
Vertical pigment line
What is the limbal girdle of vogt?
Yellowish white opacity at 3 and 9oclock
What demographic of patient gets scleromalacia perforans?
Where does lymph drain from lateral portion of eye?
- Parotid lymph gland
Where does lymph drain from medial portion of eye?
Submandibular lymph node
Where is the pupil thickest?
In the collarette
Where is the thinnest part of the pupil?
Ciliary zone, where iris joins to ciliary body
The iris stroma is continuous with what?
Stroma of ciliary body
Where is the major circle of the iris located?
In the CB
Where is the minor circle of the iris located?
In the iris stroma at the level of the collarette
What autonomic nervous system innervated the sphincter muscle?
What part of the iris is the dilator muscle found?
What receptor cells are found on the dilator muscle?
A1 - sympathetic
What causes the iris color?
Due to the amount of pigmentation of melanocytes in the anterior border layer of the iris
What is Argyll Robertson pupil?
- Poor direct and consensual response
- Constricts with near response
What causes Argyll Robertson pupil?
- Diabetic neuropathy
- Alcoholic neuropathy
what is adies tonic pupil?
- Damage to ciliary body or short ciliary nerves
- Poor pupillary light response
- Loss of accommodation
What part of the brain controls near pupil reflex?
Frontal eye fields
What part of the ciliary body creates zonular fibers?
How does the parasympathetic system work on the ciliary muscle?
Stimulates contraction which causes accomodation
How does the sympathetic system work on the ciliary muscle?
Inhibitory to contraction
What reeptors are located on the ciliary muscle?
- A2 - constriction - reduces aqueous production
- B2 - inhibitory - increases aqueous production
What happens during accommodation?
- Decreases diameter of lens
- Release tension in zonules
- Lens becomes more spherical
- The lens thickens
- Anterior surface curve steepens
- Pupil constricts (iris sphincter)
- Decreases IOP
What accounts for 80-90% of aqueous production?
What is posner-schlossman syndrome?
Repeated bouts of unilateral mild ant uveitis and very high IOP
What is haller's layer?
Large lumina in choroid that stems from short posterior ciliary arteries
What is sattler's layer?
Small lumina in choroid that stems from short posterior ciliary arteries
What layer of the retina are angiod streaks found?
Breaks in bruch's membrane
Where are drusen located in the retina?
Between bruch's membrane and RPE
What is the blood supply to choriocapillaris?
Where is the retina derived from?
What are the 10 layers of the retina from most posterior to most anterior?
- External limiting membrane
- Outer nuclear layer
- Outer plexiform layer
- Inner nuclear layer
- Inner plexiform layer
- Ganglion cell layer
- Nerve fiber layer
- Internal limiting membrane
Where are hard exudates found?
Outer plexiform layer
Where are retinoschisis found?
Outer plexiform layer
What effect does diabetes have on the crystallin lens?
Excess glucose = excess sorbitol = hyper osmolaric conditions in lens = water swells in fibers = transparency lost
What causes cortical cataracts?
What causes nuclear cataracts?
- Loss of glutathione
- Causing oxidation
What causes PSC?
- Radiation therapy
- Steroid abuse
What causes sunflower cataracts?
Intraocular trauma involving copper
What causes Christmas tree cataracts?
What causes oil droplet cataracts?
What causes snowflake cataracts?
What receptors are found on muller's muscle?
A2 - sympathetic
what are glands of zeiss?
- Oil glands for lash follicles
- Site of external hordeolum
What are glands of moll?
- Modified sweat glands (like armpit glands)
- Specialized apocrine glands
- Associated with immune defense of lash and shaft
how is the lacrimal gland autonomicly innervated?
- Vasomotor innervation
- Secretomotor innervation
What are the source of concretions?
How do carotid arteries provide circulation of eyelid?
- Internal carotid branches - Provide circulation for deeper eyelid tissue
- External carotid - Provide circulation to superficial areas of eyelid
What are the functions of tears?
- Corneal transparency
How does vitamin A affect the eyes?
- Goblet cells
- Deficiency results in bitot's spots
What autonomic nervous system controls reflex tearing
What causes spontaneous blinking?
Contraction of palpebral portion of orbi. Oculi
What causes reflex blinking?
- Touch or irritation
- CN5 senses, CN7 causes blink
- Dazzle (bright light)
- Menace(visual threat)
What is bell's phenomemon?
Eyes go up and out on lid closure for protective purposes
What muscles cause forced blinking?
palpebral and orbital portions of orbicularis
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