Sensory System

Question 1

The three layers of the wall of the eye

Answer 1

1. Outer (fibrous) coat = cornea and sclera
2. Vascular (uveal) coat = iris, ciliary body, choroid
3. Inner - retinal coat = retinal pigmented epithelium, neural retina

Question 2

3 chambers of the eye

Answer 2

Anterior, Posterior, Vitreous cavity

Question 3

Anterior chamber location

Answer 3

between cornea and iris

Question 4

Posterior chamber location

Answer 4

between back of iris and lens with attached fibers

Question 5

Vitreous cavity location

Answer 5

between lens and retina

Question 6

Cornea appearance and shape

Answer 6

Transparent and convex shape aids in focusing light onto retina

Question 7

Blood supply of central cornea

Answer 7

Avascular; no blood or lymph in central portion. Central part gets nutrients via diffusion from aqueous humor.

Question 8

Blood supply of peripheral cornea

Answer 8

Supplied by blood from limbus vessels.

Question 9

Number of layers in cornea

Answer 9

5

Question 10

Transplantation of cornea

Answer 10

Successful, and lacks rejection

Question 11

5 layers of the cornea

Answer 11

Epithelium, Bowman’s layer, Stroma, Decemet’s membrane, Corneal endothelium C-BEDS

Question 12

Epithelium layer description

Answer 12

• Anterior layer
• non keratinized stratified squamous epithelium w/small microvilli
• Pain receptors via trigeminal/oculomotor
• can regenerate

Question 13

Bowman’s layer description

Answer 13

• layer of type 1 collagen
• can not regenerate
• part of the Stroma layer

Question 14

Stroma layer description

Answer 14

• lattice of type 1 and type 5 collagen fibers

- rich ECM of chondroitin and keratan sulfate

Question 15

Decemet’s membrane description

Answer 15

• thick(5-10um) basement membrane
• contains type 7 collagen
• produced by corneal epithelium

Question 16

Corneal endothelium description

Answer 16

• surface faces anterior eye chamber

- impermeable intercellular spaces prevent leakage of fluid into corneal stroma

Question 17

Sclera connective tissue

Answer 17

dense irregular connective tissue, opaque

Question 18

Purpose of the sclera

Answer 18

provides protection and structure support and insertion point for extraocular muscles

Question 19

Limbus definition and location

Answer 19

corneoscleral junction; adjacent to trabecular meshwork and canal of schlemm

Question 20

Limbus contents

Answer 20

Aqueous humor(fluid resembles plasma, but less proteins)

Question 21

Production of aqueous humor

Answer 21

Ciliary body epithelium

Question 22

Pathway of aqueous humor

Answer 22

Produced by ciliary body to anterior chamber to trabecular network to canal of schlemm to aqueous veins to episcleral veins.

Question 23

Obstruction of aqueous humor

Answer 23

Leads to increased pressure in the eye; glaucoma

Question 24

3 regions of the middle coat

Answer 24

Iris, Ciliary body, choroid

Question 25

Description of choroid

Answer 25

• highly vascular nutrient supplier to all eye layers

- contains melanin

Question 26

Number of layers in choroid

Answer 26

3

Question 27

Names of three layers in choroid

Answer 27

Bruch’s membrane, Choriocapillaris, Choroidal stroma

Question 28

Description of Bruch’s membrane

Answer 28

• innermost layer
• collagen and elastic fibers and basal lamina
• derived from pigmented epithelials cells and endothelial cells of fenestrated capillaries

Question 29

Description of Choriocapillaris

Answer 29

• fenestrated capillaries

- supply retina and fovea

Question 30

Description of Choroidal stroma

Answer 30

• collage and elastic fibers
• large blood vessels
• some smooth muscle
• melanocytes
• autonomic neurons

Question 31

Components of Ciliary Body

Answer 31

Uveal(middle layer of cornea) and neuroepithelial portion

Question 32

Uveal description of Ciliary Body

Answer 32

-outer layer of choroid(supracilliaris) and ciliary muscle attached to suspensory ligament and layer of fenestrated capillaries

Question 33

Neuroepithelial description of Ciliary Body

Answer 33

• 2 layers of ciliary epithelium
• outer pigmented layer continuous with retinal pigmented epithelium
• inner nonpigmented layer

Question 34

Ciliary processes

Answer 34

Anterior portion of Ciliary body folded to form ciliary processes

Question 35

epithelium near ciliary body

Answer 35

Produces aqueous humor

Question 36

Description of Iris

Answer 36

• Continuation of ciliary body.
• anterior part of middle coat(uvea)
• has smooth muscle which controls the size of pupil

Question 37

Layers of smooth muscle of Iris

Answer 37

2 smooth muscle layers; circular and radial

Question 38

Autonomics of Iris

Answer 38

Constrictor muscle: parasympathetic

Dilated pupil: sympathetic

Question 39

Description of lens

Answer 39

• avascular, transparent, and elastic

- biconvex in shape

Question 40

Lens is enclosed in

Answer 40

thick basement membrane like material called the capsule

Question 41

Change of shape of the lens mediated by

Answer 41

tension on the suspensory ligament fibers

Question 42

Description of vitreous humor

Answer 42

• gel like
• transparent
• composed of water and hyaluronic acid
• fills the vitreous chamber
• keeps lens and retina in place

Question 43

Description of Cataract

Answer 43

-opacity of lens; associated with aging

Question 44

Layers of Retina

Answer 44

Retinal pigmented epithelium, layer of rods and cods

Question 45

Description of retinal pigmented epithelium

Answer 45

• absorbs scattered light rays
• phagocytosis of worn out discs shed from rods
• stores and releases vitamin A

Question 46

Structure retinal pigmented epithelium closely associated with

Answer 46

associated with Choroid; space can occur between RPE and retina where dislodging can occur.