Exam #2: Eye Flashcards

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1
Q

What are the three layers of the eye?

A

1) Fibrous/ Corneoscleral
2) Vascular/ Uvea
3) Retina

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2
Q

Corneoscleral Layer of the Eye

A
  • Most superficial part
  • Cornea= anterior 1/6
  • Sclera= posterior 5/6
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3
Q

Where does the uvea get its blood supply from?

A

Ophthalmic Artery

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4
Q

Vascular Layer of the Eye/ Uvea

A
Iris= anterior, eyecolor 
Choroid= posterior, dark heavily pigmented portion
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5
Q

Retinal Layer

A
  • Neural/ innermost layer of the eye
  • Anterior= thin & nonvisual
  • Posterior= thin & visual
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6
Q

What marks the separation between the anterior & posterior portion of the retina?

A

Ora Serrata

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7
Q

What are the different chambers of the eye?

A
  • Eye is divided into an anterior & posterior segments by the Ora Serrata
  • Anterior segment is further divided into the anterior & posterior chambers by the iris
  • Posterior segment contains the vitreous chamber
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8
Q

Contents of the Anterior Segment

A
  • Aqueous Humor
  • Iris (vascular)
  • Ciliary Body & Muscle
  • Lens (avascular)
  • Cornea (avascular)
  • Anterior Sclera
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9
Q

Contents of the Posterior Segment

A
  • Vitreous Humor
  • Visual Retina
  • RPE
  • Posterior Sclera
  • Uvea
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10
Q

Aqueous Humor vs. Vitreous Humor

A
  • Aqueous= anterior chamber, provides stability & nutrition to keep the avascular structures alive
  • Vitreous= vitreous chamber (posterior segment), more jelly-like than aqueous humor b/c of 1% collagen)
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11
Q

What does dehydration of the vitreous humor lead to?

A
  • Detached retina

- The vitreous humor helps keep the retina on the vascular layer & choroid

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12
Q

Cornea

A
  • Anterior 1/6 of the eye
  • Transparent
  • Avascular
  • Provides 2/3 of the refractive power of the eye (more than lens)
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13
Q

What are the five layers of the cornea from outside to inside?

A

1) Corneal Epithelium
2) Bowman’s Membrane
3) Corneal Stroma
4) Descemet’s Membrane
5) Corneal Endothelium

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14
Q

Corneal Epithelium

A
  • Stratified squamous epithelium (non-keratinized)
  • Contains microvilli (prevent drying out)
  • Contains Ferritin (protects from UV damage)
  • Regenerates
  • Blink reflex (CN V & VII)
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15
Q

Bowman’s Membrane

A
  • Anterior basement membrane
  • Does not regenerate–> scarring
  • Provides strength to the cornea
  • Barrier to infections
  • Terminates at corneoscleral limbus
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16
Q

Corneoscleral limbus

A
  • Transition point of cornea & sclera

- Contains stem cell for the corneal epithelium

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17
Q

Corneal Stroma

A
  • Also called the Substantia Propria
  • 90% of corneal thickness
  • Contains proteoglycans & type V collagen organized in 90 degree lamellae
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18
Q

Descemet’s Membrane

A
  • Posterior basement membrane
  • Regenerates
  • Thickens with age
  • Helps maintain normal curvature of the eye through pectinate ligaments
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19
Q

Pectinate Ligaments

A

Connect the sclera to the ciliary body & help maintain the normal curvature of the eye

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20
Q

Corneal Endothelium

A
  • Simple squamous epithelium
  • Joined by zonula adherens, zonula occludens, & desmosomes
  • Adjacent to aqueous humor
  • Limited proliferative ability
  • Responsible for nearly all metabolic exchanges of the cornea & contains fluid pumps for hydration
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21
Q

Sclera

A
  • Posterior 5/6 of the eyeball
  • “White” of the eye
  • Contains though fibrous connective tissue (Collagen & Elastic Fibers)
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22
Q

What are the three layers of the sclera?

A

1) Episcleral
2) Substantia Propria
3) Suprarachnoid Lamina

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23
Q

Episcleral Layer

A
  • Outer layer of the sclera

- Contains tenon’s space

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24
Q

Tenon’s Space

A

A space between tenon’s capsule & periorbital fat that gives the eye room to move in

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25
Q

Substantia Propria

A
  • Intermediate layer of the sclera

- Contains Tenon’s Capsule

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26
Q

Tenon’s Capsule

A

Connection to the extra-ocular muscles

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27
Q

Suprarachnoid Layer

A
  • Inner layer of the sclera
  • Attachment of the sclera to the choroid
  • How the sclera gets nutrients
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28
Q

Iridocorneal Angle

A

Corner of the cornea & iris

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29
Q

Canal of Schlemm

A

Scleral venous sinus i.e. apparatus for outflow of aqueous humor

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30
Q

Contents of the Uvea

A

1) Iris
2) Ciliary Body
3) Choroid

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31
Q

Iris

A
  • Most anterior portion of the uvea

- Color part of the eye (no pigment= pink)

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32
Q

Pupil

A

Opening between the two edges of the iris

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33
Q

Dilator Pupillae

A
  • Radially arranged smooth muscle fibers that open the pupil

- SNS innervation

34
Q

Sphincter Pupullae

A
  • Circularly arranged smooth muscle fibers that close the pupil
  • PNS innervation
35
Q

Ciliary Body

A
  • Anterior to the Ora Serrata
  • Continuous with the iris
  • Produces aqueous humor (specifically, the ciliary processes)
  • Lined by two layer of simple columnar epithelium separated by a basement membrane
36
Q

What are the two layers of the Ciliary Body?

A

1) Pigmented

2) Non-pigmented

37
Q

Pigmented

A
  • Outer layer

- Helps reduce glare

38
Q

Non-pigmented

A
  • Inner layer

- Important for transferring fluids

39
Q

Ciliary Processes

A
  • Part of the Ciliary Body
  • 75 radial radial fibers that anchor to the lens
  • Suspend the lens
  • Produce aqueous humor
  • Contains tight junctions that create a blood-aqueous barrier
40
Q

Floater

A

When blood passes the blood-aqueous barrier established by the ciliary processes

41
Q

Describe the flow of aqueous humor.

A

1) Ciliary process
2) Behind the iris
3) Out the pupil
4) Toward iridocorneal angle
5) Canal of Schlemm
6) Diffusion into venous network

42
Q

Open Angle Glaucoma

A
  • Disruption of the Canal of Schlemm (aqueous humor outflow)
  • Gradual increase in symptoms/ intraocular pressure
43
Q

Closed Angle Glaucoma

A
  • Closure of the iridocorneal angle

- Rapid onset of symptoms/ increase in introocular pressure

44
Q

What are the two different fibers of the ciliary muscle?

A

1) Longitudinal

2) Circular

45
Q

Longitudinal Fibers of Ciliary Muscle

A

Pull on lens to flatten for far vision

46
Q

Circular Fiber of Ciliary Muscle

A

Reduce tension on lens for near vision

47
Q

Choroid

A
  • Dark layer of the posterior eye that is between the sclera & retina
  • Provides nutrition to both layers
  • Heavily pigmented by melanocytes
  • Functions to reduce glare
48
Q

What are the two layers of the choroid?

A

1) Choriocapillary layer= (outer) vascular layer of the choroid
2) Bruch’s Membrane (inner)

49
Q

What are the five layers of bruch’s membrane?

A

Bruch’s membrane is the basement membrane for the capillaries of the choroid

1) Basement membrane for capillaries
2) Collagen Layer
3) Elastic Layer
4) Collagen Layer
5) Basement membrane for RPE

50
Q

Neural Retina

A

Innermost layer of the retina

  • Non-photosenstive= anterior to ora serrata
  • Photosensitive= posterior to ora seratta
51
Q

Fovea

A
  • Point of greatest visual acuity
  • Thinnest part of retina
  • Cones only
52
Q

Optic Disc

A
  • Blind spot where the optic nerve exits the eye

- No photoreceptors

53
Q

Macula Lutea

A

Yellow area that surrounds the fovea

54
Q

RPE

A
  • Retinal Pigmented Epithelium
  • Heavily pigmented
  • Controls nutrient delivery & waste removal to/from the retina
55
Q

Detached Retina

A

Mechanical separation of the neural retina & RPE

56
Q

What are the four groups of cells found in the retina?

A

1) Photoreceptors
2) Conducting Neurons
3) Association & Other Neurons
4) Support Cells

57
Q

Photoreceptors

A
  • Rods

- Cones

58
Q

Conducting Neurons

A
  • Bipolar Neurons= synapse between photoreceptor & ganglion

- Ganglion= synapse between bipolar neuron & optic nerve

59
Q

Association & other neurons

A
  • Horizontal
  • Centrifugal
  • Interplexiform
  • Amacrine
60
Q

Supporting Cells

A
  • Muller= transport nutrients to rods & cones
  • Microglia
  • Astrocytes
61
Q

What are the 10 layers of the retina?

A

1) RPE
2) Rods & Cones
3) Outer Limited Membrane (apical muller cells)
4) Cell Bodies of the Rods & Cones
5) Outer Plexiform Layer (synapse to bipolar cells)
6) Inner Nuclear Layer (Bipolar cell bodies)
7) Inner Plexiform Layer (Synapse to ganglion cells)
8) Ganglion Cell Layer (Cell bodies of ganglion)
9) Optic Nerve Fibers (Axons of ganglion)
10) Inner Limiting Membrane (Basement membrane of muller cells)

62
Q

RPE

A
  • simple cuboidal cells

- villi intermesh with rods & cones to remove waste/ discs (restores photosensitivity)

63
Q

Rods

A
  • low intensity light (black, gray, white)
  • most abundant
  • shed discs
  • plasma membrane is continuous
  • rhodopsin
64
Q

Cones

A
  • high intensity light (red, green, blue)
  • shed discs, but not as much as rods
  • less numerous
  • plasma membrane is discontinuous
  • iodopsin
65
Q

Outer-segment of photoreceptors

A

photosensitive discs

66
Q

Inter-segment of photoreceptors

A

machinery of the cell

67
Q

Diabetic Retinopathy

A
  • Most common cause of blindness in developed countries

- Elevated glucose causes blood vessels to become fragile & bleed, inducing edema & neovascularization

68
Q

Neovascularization

A

Formation of new blood vessels

69
Q

Non-Proliferative vs. Proliferative Diabetic Retinopathy

A
  • Non-proliferative= NO neovascularization

- Proliferative= Neovascularization

70
Q

Age Related Macular Degeneration

A
  • Macula & Fovea Centralis start to degenerate
  • Characterized by Drusen
  • Macular edema
  • Intra-retinal bleeding
71
Q

Drusen

A
  • Hallmark of macular degeneration

- Lipid accumulation in macula

72
Q

Dry vs. Wet Macular Degeneration

A
Dry= No neovascularzation
Wet= Neovascularization
73
Q

What are the three parts of the lens?

A

1) Lens Capsule
2) Equatorial Zone
3) Subcapsular Epithelium

74
Q

Lens Capsule

A
  • Acellular
  • Basement membrane of lens
  • Outside
  • Composed of type IV collagen & proteoglycans
75
Q

Equatorial Zone of Lens

A
  • Contains the germinal zone that creates new lens fibers

- Consists of a simple cuboidal epithelium

76
Q

Crystallin

A

Protein in lens fibers

77
Q

Cataracts

A

Elasticity changes of the lens with age & an increase in opacity

78
Q

Vitreous Body

A
  • 99% H20
  • 1% gel
  • Very slow to exchange oxygen & nutrients (can be used forensically)
  • Should be clear, but dehydration can lead to collagen break-off causing floaters
79
Q

Palpebral Conjunctiva

A
  • Conjunctive lining the eyelid

- Stratified columnar epithelium with goblet cells

80
Q

Bulbar Conjunctiva

A

Reflection of the conjunctiva onto the eyeball itself