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Question 2

Optical tissues: 4 layers

Answer 2

Vitreous body (vitreous humorLens – Biconcave diskAqueous humor Cornea – most anterior

Question 3

Cornea

Answer 3

anterior 1/6 of eye wallRefractive(most of light bending occurs here)Connective TissueTransparent - avascular

Question 4

Lens

Answer 4

Biconcave disk Refractive - for adjustable fine focusCellstransparent

Question 5

Aqueous humor

Answer 5

mostly water liquid b/w cornea and lens - clearProvides nutrients and metabolites to both tissuesAnterior chamber: b/w cornea and irisPosterior chamber: b/w iris and lens

Question 6

Vitreous body (vitreous humor)

Answer 6

accellular gel like substance filling space posterior to lensGives eye physical supportMostly water but has proteoglycans and hyaluronic acid gell formation• Also has fibrillary collagen (type II)

Question 7

Eye wall tissues: 3 layers

Answer 7

Outer layer - regular dense connective tissue Cornea ScleraMiddle layer – very loose CT Choroid Iris Cilliary body Inner layer: retina

Question 8

Cornea: 5 layers

Answer 8

Epithelium – stratified squamous not keratinized• Mostly protective barrier• Highly innervatedBowmans Membrane: dense CT of collagen fibrils - secondary protectionStroma – dense regular CT (highly organized)• Arranged collagen fibrils (type I) - NO light scattering• Absorbs fluid - to much -> eye swelling and opacityDescemet’s membrane: endothelium basement mambraneEndothelium – simple squamous (low cuboidal)• fluid balance of stroma - secretes ions into anterior chamber - water follows

Question 9

Lens epithelium

Answer 9

Single layer of cuboidal epithelial cells on anterior surface

Question 10

Lens capsule

Answer 10

elastic basement membrane surrounding entire lens

Question 11

Lens fiber cells

Answer 11

“dead cells” that make up majority of lens• no nuclei or organelles, “bags” of citrullins (like RBC’s)• uniform (little light scattering and transparent), full of proteins• interdigitation• Avascular and get nutrients from aqueous humor of anterior chamberEnlarges as age – appositional growth (cells cant slough off)• Cells we’re born with are on inside… newer cells on outside

Question 12

Sclera

Answer 12

continuous with cornea (posterior 5/6 of eye wall)whiteAttachment for extraocular musclesno endothelium, more hydrated ->scatters light

Question 13

Choroid

Answer 13

in middle layer of eye wallloose connective tissue; posterior to anterior (everywhere retina is)- Very vascular- Identified by its heavy pigmentation- many white blood cells

Question 14

Cilliary body

Answer 14

In middle layer of eye wallchoroid widens into cilliary body- Loose CT w/ many melanocytes- Embedded w/ cilliary smooth muscles- very uniform tissue

Question 15

Iris

Answer 15

most anterior of eye wall middle layer; disk with hole in it (pupillary hole)

Question 16

Retina

Answer 16

2 layers: neural and pigmented epitheliumdual blood supply: choroidal circ and central retinal artery10 layerscontains photoreceptors

Question 17

Cilliary epithelium

Answer 17

2 layers: outer pigmented (continuous w/ pigmented retinal ep.) and inner unpigmented (continuous w/ neural retina)secretes aqueous humour -> maintains intraocular pressure

Question 18

Iris

Answer 18

consists of stroma and epitheliumStroma – anterior iris; very loose CT (no epithelial lining)• Highly vascular, melanocytes2 layers of pigmented epithelium cells lining posterior surface

Question 19

Sphincter pupillae

Answer 19

conventional SM - contracts iris Parasympathetic innervation

Question 20

Dilator Pupillae

Answer 20

not true smooth muscle (myoepithelial cells)-Microvilli processes that attach to edge of pupil - contraction pulls iris open -> dilationSympathetic innervation

Question 21

Sympathetic innervation

Answer 21

attach lens and ciliary bodies – composed of fibrillin

Question 22

 Aqueous Humor

Answer 22

Maintains positive pressure w/in the eyepumped into eye via cilliary epitheliumgives nutrients to corneaoutflow through canal of schlemm

Question 23

ophthalmic artery

Answer 23

penetrates eye wall through sclera -> branches into capillaries in choroid -.> supplies PRE

Question 24

Horizontal Cells

Answer 24

interconnect photoreceptor cell axons and bipolar cell dendrites (outer plexiform layer)

Question 25

amicrine cells

Answer 25

interconnect bipolar axons and ganglion cell dendrites

Question 26

muller cells

Answer 26

supporting cells around neural retina neurons

Question 27

Retinal pigmented layer

Answer 27

nutrient transport to photoreceptor cellsblood retinal barrierphagocytosis -> aids renewal of photoreceptorslight absorption -> pigmented