10-23 Orbit II Flashcards
A: The eye is an orb measuring about ____ mm in diameter and is protected by _____ ____
B: What are the 3 layers of the eye
A: Eye is an orb measuring about 25 mm in diameter and is protected by PERIORBITAL FAT
B: ºSclera[corneo-scleral layer] <— xtraocular muscles attach
º[Choroid uveal layer],
ºRetina
- Describing the Sclera [corneo-scleral layer]*
A: What is the Outer eye composed of?
B: What is [Tenon’s Capsule] and how is it related to the POST 5/6 of the eye?
C: Describe the Anterior 1/6th of the eye
E: Sclera is composed of __ layers and receives metabolites from ___ ___ and ___ ___. External environment contributes some ___ directly to the Sclera.
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F: Describe the Cornea
*Sclera [corneo-scleral layer] *
A: outer= dense connective tissue arranged in parallel, concentric bundles
C: ANT 1/6=is TRANSPARENT and AVASCULAR–>FORMS CORNEA
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D: Limbus= point where cornea meets sclera
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E: Sclera is composed of 5 DISTINCT layers receiving metabolites from AQUEOUS HUMOR & LIMBUS VESSELS.
EXT environment contributes some O2 directly to Sclera.
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F: Cornea= ANT 1/6 of eye with smaller radius of curvature, tht serves as MAIN refracting medium for focusing light onto retina
Describe [Choroid uveal layer] of EYE < 4 >
- Middle vascular layer containing eye ciliary vessels & nerve supply
- OCCUPIES POST 5/6 of eye; ending at limbus by forming free-floating iris
- Heavily pigmented using melanocytes-> which help absorb stray photons
- At limbus, forms Ciliary body
In Ciliary body of the [____ layer] of the Eye you will find Ciliary m. , Ciliary process and [Canal of Schlemm].
Describe the Ciliary muscles [3]
Ciliary body of the [Choroid uveal layer] of Eye
- Ciliary muscles*
1. At rest (far objects), lens is flattened
- Innervated by parasympathetics causing circumferential fiber constriction—>lens thicken (near objects)
- connected to lens capsule by [Zonular suspensory fibers]
In Ciliary body of the [____ layer] of the Eye you will find Ciliary m. , Ciliary process and [Canal of Schlemm].
Describe the Ciliary Process [4]
Ciliary Body of the [Choroid uveal layer] of Eye
- Ciliary Process*
1. Produces clear, watery fluid similar to CSF {AKA Aqueous humor}
2. Houses metabolites to maintain cornea & lens
- Produced by ACTIVE process mediated by double epithelia layer of cells
- Houses intraocular pressure ~15 mmHg due to balanced rate of production & reabsorption–>Stabilizes lens & cornea
In Ciliary body of the [____ layer] of the Eye you will find Ciliary m. , Ciliary process and [Canal of Schlemm].
Describe the [Canal of Schlemm] [3]
B: This Canal is also known as the ___ ___ ____
Ciliary Body of the [Choroid uveal layer] of Eye
- [Canal of Schlemm] *
1. REABSORBS Aqueous Humor
- Circumferential canal immediately ANT to iris at corneo-scleral junction lined w/endothelium & continuous w/venous system
- Covered with [Trabeculae meshwork]—>pumps aqueous humor from ANT chamber to Schlemm’s Canal
B: AKA: SCLERAL VENOUS SINUS
Aqueous Humor Blockage or defective pumping by the [____ ____] inside the [___ __ _____] can lead to INC _____ and _______
Aqueous Humor Blockage or defective pumping by [Trabeculae meshwork] inside Ciliary Body [Canal of Schlemm] —> INC intraocular pressure AND Glaucoma!
A: IRIS arises from ___ ___ and forms a ____ ____. It divides the ____ part of the eye into ANT and POST chambers.
B: Describe the IRIS composition
C: Describe the 2 muscles of the Iris
IRIS arises from CILIARY BODY and forms an ADJUSTABLE DIAPHRAGM. It divides the ANTERIOR eye into ANT and POST chambers.
C: 1. [Sphincter pupillae ]: circumferential m. located @ Iris free margin = constricts pupil upon CN3 PARAsympathetic control
Recite the ROUTE OF PASSAGE of AQUEOUS HUMOR [4]
MADE in POST chamber by [Ciliary Process]–>
flows around Lens—>
through pupil into ANT chamber—>
Pumped Out ANT chamber into [Canal of Schlemm] by its surrounding [Trabeculae meshwork]
Lens [5]
- Elastic biconvex body of VERY elongated epithelial cells
- Contain crystalline protein & adjacent cells fuse together
- Lose elasticity as we age (x>50)–>PRESBYOPIA
- Mature lens has fewer nuclei
- Lens Clouding = CATARACTS
Postremal chamber
Space behind lens [POST 5/6 of eye] thts filled with [gel-like VITREOUS HUMOR]—->cushions retina & maintains round eyeball shape during rapid mvmnt
RETINA
A: Function
B: Location
C: Name the 10 Retina Distinct Layers
RETINA
A: photosensitive neural layer tht transduces photon light energy—>CNS action potentials (vision)
C:
1. [iNNer limiting membrane] = ON TOP
- Optic nerve layer
- Ganglion cell layer
- [ Inner plexiform synaptic layer zone ]
- Inner NUCLear layer
- [Outer plexiform synaptic layer zone]
- Outer NUCLear layer
- [ Outer limiting membrane ]
- [ROdS/CONeS Photoreceptor] layer
- PIGMENTED EPITHELIUM
The RETINA is made of 10 DISTINCT Layers
*Describe its [iNNer limiting membrane] layer
- Most Superficial layer & tight junction found between processes of Muller cells
- Forms Blood:retinal barrier that retinal blood vessels sit on top of , next to vitreous body
The RETINA is made of 10 DISTINCT Layers
Describe its ……
A: [Optic nerve] layer
B: [Ganglion Cell Layer]
C: [Inner plexiform synaptic layer zone]
D: [Inner NUCLear layer]
(listed to SUP to Deep)
RETINA
A: ON=ganglion cell axons all converging @ optic disc —-> OPTIC NERVE
C: iPSLZ= houses synapses between bipolar interneurons, amacrine cells & ganglion cells
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D: [Inner NUCLear layer]= All retinal INTERneuron cell BODIES & Muller cell BODIES
The RETINA is made of 10 DISTINCT Layers
Describe its ……
A: [Outer plexiform synaptic layer zone]
B: [Outer NUCLear layer]
C: [Outer limiting membrane]
(listed to SUP to Deep)
RETINA
A: OPSLZ= houses synapses between photoreceptors, bipolar interneurons & horizontal interneurons
B: [Outer NUCLear layer]=Cell bodies of ALL Rods & Cones
C: [Outer limiting membrane] =EXT limit of Muller supporting cells located at junction of rods & cones and their respective cell bodies
The RETINA is made of 10 DISTINCT Layers
A: Describe [rODS/cONES Photoreceptor] layer
B: [PIGMENTED EPITHELIUM:
RETINA
A: [RODS & CONES] =photosensitive area of photoreceptors that transduce photon energy–>CNS Action potentials (vision)
B: PE= MOST DEEP Retina layer that absorbs stray photons & provide metabolic support to photoreceptive rod/cone tips
1) What change in Retina layers occurs in the Fovea?
2) Photoreceptors found at the fovea?
3) Type of Blood vessels at Fovea?
- At center of visual axis, retina layers are Displaced Laterally to allow photons to directly reach Cones
- Only [CONE-type photoreceptors] at Fovea
3) NO BLOOD VESSELS at Fovea!–>creates distinct retina area known as MACULA. .
- What is the Optic Disc
- ___ ___ ___ enter/exit eye through the Optic Disc
- What is the “Blind Spot”
- Explain why this is a convenient spot to observe CSF pressure changes.
- Optic Disc= area where [ganglion cell Axons] CONVERGE and form an Optic Nerve {AKA Optic Disc}
- RETINA BLOOD VESSELS enter/exit Eye through this Optic Disc
- There are NO PHOTORECEPTORS AT OPTIC DISC/NERVE converge point —-> “Blind Spot”
- CSF flows around Optic Disc/nerve covered by dura mater.
A: Papilledema
B: How can CSF result in swelled retinal arteries
C: How are these dysfunctions detected?
A: Papilledema= when INC in CSF pressure pushes on back of Optic disc & causes it to bulge!
C: BOTH detected/viewed by Ophthalmoscopic Exam
1) Which Orbit Wall is the THICKEST? Which is bone is it primarily?
2) Which Orbit Wall has a center axis angled at 22.5º? What structure does it point to?
3) The SUPERIOR/___ of the Orbit is composed of what 2 bones?
1) LATERAL WALL=THICKEST–>Made mostly of Zygomatic Bone
2) Orbit APEX has center axis pointing at SELLA TURCICA at 22.5º
3) SUPERIOR/ROOF of Orbit = FRONTAL + [some sphenoid lesser wing]
