07a: The Eye Flashcards by Nuna H

The eye is comprised of three principal layers called (X). List them.

X = Tunics

Corneoscleral
Uveal
Retinal

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Thick curved structure at anterior portion of eye.

Cornea

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Cornea (is/isn’t) transparent and has which layer(s)?

Is;

Stratified squamous (NK) epithelium
Bowman’s membrane
CT stroma
Descemet’s membrane
Endothelium

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White of the eye.

Sclera

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Sclera (is/isn’t) transparent and is composed of which type of tissue?

Isn’t;

Dense irregular CT

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Limbus of the eye is what?

Junction between cornea and sclera

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Lamina cribrosa of eye is:

portion of sclera at back of eye that’s disrupted by penetrating axons/blood vessels

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The (X) is found in the uveal layer of the eye and forms aperture called (Y) to admit light into eye.

X = iris;
Y = pupil

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Size of pupil is controlled by:

Sphincter and dilator pupillae

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Sphincter pupillae controlled by (X) and dilated pupillae controlled by (Y).

X = parasympathetic NS
Y = sympathetic NS

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The ciliary body is located immediately behind (X). It contains (Y). What underlies it?

X = iris;
Y = ciliary processes;
Z = ciliary muscle

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Immediately behind ciliary body is the (X), which extends as a layer on underside of (Y).

X = choroid;
Y = sclera

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(X) structure of eye contains enormous amount of pigment to absorb stray light.

X = choroid

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Photoreceptors supplied by dense capillary plexus called (X), which is contained in (Y) structure of eye.

X = choriocapillaris;
Y = choroid

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Bruch’s membrane separates:

Retina and choroid layers

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Retinal tunic consists of which layers? Star the one closest to choroid layer.

Neural retina

2. Retinal pigment epithelium layer (RPE)*

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Retinal pigment epithelium is (single/multi)-layered and composed of (simple/cuboidal/columnar) cells containing (X).

Single; cuboidal

X = pigment

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List the spaces in the eye.

Anterior chamber
Posterior chamber
Vitreal chamber

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Anterior chamber walls.

Cornea (anterior) and Iris/lens (posterior)

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Posterior chamber walls.

Ant: iris
Post: zonules
Medial: lens
Lateral: ciliary body

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(X) are small CT fibers attached to ciliary body and (Y) to hold (Y) in place.

X = Zonules;
Y = lens

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Posterior chamber of eye contains (X) fluid.

X = clear aqueous humor

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Anterior chamber of eye contains (X) fluid.

X = clear aqueous humor

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T/F: Fluid can travel between posterior and anterior chambers of eye.

True

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(X) chamber is between (Y) and the back of the eye. It's filled with what fluid?

``` X = vitreous Y = lens ``` Vitreous humor

Vitreous humor has which consistency/color?

Clear, gel-like

(X) is mucous membrane that's continuous with cornea and and lies on top of (Y).

``` X = conjunctiva; Y = sclera ```

List the portions of the conjunctiva and what each one lies on.

1. Palpebral (on back of eyelid) | 2. Bulbar (on sclera)

Tear film of fluid covers (X) structure of eye. List its layers.

X = cornea; 1. Outer lipid layer 2. Middle aqueous layer 3. Inner mucous layer

Innermost (X) layer of tear film is produced by (Y).

``` X = mucous; Y = goblet cells of conjunctiva ```

Middle (X) layer of tear film is produced by (Y).

``` X = aqueous Y = lacrimal glands ```

Outermost (X) layer of tear film is produced by (Y).

``` X = lipid Y = tarsal (Meibomian) glands of eyelid ```

An optically smooth surface of eye is possible, despite micrivilli projections of (X) epithelium, because (Y) fills in the gaps.

``` X = corneal; Y = innermost mucous layer of tear film ```

Which layer of tear film has defensive/protective properties due to presence of (X).

Middle aqueous layer; Lactoferrin, lysozyme, IgA

T/F: Epithelium of cornea is highly innervated

True - very sensitive to touch

T/F: Cornea is as sensitive to touch as fingertips.

False - 10x more sensitive

Corneal epithelium has (X), preventing anything from getting in/out.

X = tight junctions

Basement membrane of corneal endothelium is called:

Descemet's membrane

Corneal epithelium has (high/low) stem cell population and is (very/minimally) metabolically active.

Low; Very

Cornea is transparent due to fluid being constantly pumped (into/out) across (X) cells on its (inner/outer) margin.

Out; X = endothelial Inner

(High/low) organization of (X) in cornea when compared to sclera also contributes to its transparency.

High; | X = Type I collagen fibrils

The cornea is (vascular/avascular), meaning it must receive oxygen/nutrients from (X).

Avascular; | X = aqueous humor and air

Stem cells of cornea are located at (X).

X = limbus

Cells of lens are very (small/large) and formally called (X).

Large; | X = lens fibers

What contributes to (color/transparency) of lens?

Transparency; 1. Anucleate cells 2. Highly organized crystalline proteins ("crystallins") in lens fibers

"Cataracts" is a condition in which:

Lens becomes cloudy/opaque due to conformational change in crystallin molecules of lens fibers

In near focus, lens is which shape?

Round

In distant focus, lens is which shape?

Ellipsoid

Pulling on zonules will make lens more (round/ellipsoid).

Ellipsoid

Contraction of ciliary muscle will make lens more (round/ellipsoid) because it (increases/decreases) tension on (X).

Round; Decreases; X = zonules

You think you see something in the distance, so you try and focus on the object to ID it. Your ciliary muscles (contract/relax) to allow (rounder/flatter) lens and (less/greater) bending of light.

Relax; flatter; less

Presbyopia is a condition in which (X) loses its (Y).

``` X = lens; Y = flexibility ```

In the eye, the epithelium of (X) filters blood and a (high/low)-protein plasma is (passively/actively) transported into (X) chamber to provide nourishment for avascular structures.

X = ciliary body; Low; Actively; X = posterior

Production of aqueous humor is achieved by:

Ciliary body epithelium

"The angle" in the eye is between (X) structures and contains (Y).

``` X = iris and cornea; Y = trabecular meshwork ```

(X) passes through trabecular meshwork and enters (Y) before going to (Z).

``` X = aqueous humor; Y = canal of Schlemm; Z = episcleral venous system ```

In most basic terms, glaucoma refers to condition in which:

intra-ocular pressure is increased

What are the two types of glaucoma?

1. Open-angle | 2. Closed-angle

In open-angle glaucoma, what are possible underlying issues?

1. Increased production of aqueous humor by ciliary body | 2. Particulate matter blocking trabecular meshwork

In closed-angle glaucoma, what are possible underlying issues?

Angle of eye too closed (due to displacement of iris), blocking aqueous humor drainage

Vitreous humor is composed of:

1. Hyaluronic acid 2. Proteoglycans 3. Type II collagen 4. Water

List layers of retina, from innermost (near vitreous chamber) to outermost (near RPE).

1. GCL (ganglion cell layer) 2. IPL (inner plexiform) 3. INL (inner nuclear) 4. OPL (outer plexiform) 5. ONL (outer nuclear) 6. Photoreceptors (rods and cones)

There are several types of cells in the (X) layer of retina. List them.

X = INL 1. Bipolar 2. Horizontal 3. Amacrine 4. Muller

Cell bodies of photoreceptors make up (X) layer of retina.

X = ONL

Photoreceptors make connections with dendrites of other neurons in (X) layer of retina.

X = OPL

(X) cells receive signals from photoreceptors and relay the signals to dendrites of (Y) that are present in (Z) layer of retina.

``` X = bipolar; Y = retinal ganglion cells; Z = IPL ```

Ganglion cell axons that are (myelinated/unmyelinated) travel across (inner/outer) eye surface and head to (X), where they're (myelinated/unmyelinated).

Unmyelinated; Inner; X = optic disc Myelinated

At optic disc, (X) axons (enter/exit) by penetrating the (Y).

X = ganglion cell; Exit; Y = sclera

Papilledema is a condition in which (X) causes visible (Y).

``` X = increase in intracranial pressure Y = swelling of optic disc ```

In (X), a specialized part of retina, all cell layers besides (Y) have been pushed aside.

``` X = fovea; Y = cones ```

T/F: There are about 100x times cones than there are rods in fovea.

False - no rods! only cones

Cones in fovea are (thicker/thinner) and have (higher/lower/equivalent) packing density as other parts of retina.

Thinner; higher

(X) is area of central vision.

X = fovea

What allows for such high resolution vision in fovea?

Dense packing of cones

Inner (X) portion of retina blood supply.

X = 2/3 Branches of central retinal artery

(X) form sockets for photoreceptors to nestle in.

X = RPE cells

The eyes developed as outpouchings of (X) known as (Y). This is why retina and optic nerve are both part of (PNS/CNS).

X = diencephalon Y = optic stalk CNS

During development, inner layer of optic cup will eventually form (X) and outer layer will form (Y). Space between them is called (Z).

``` X = retina; Y = RPE Z = intraretinal space ```

A blow to the head can cause retinal detachment, which is separation of (X) from (Y).

``` X = retina; Y = RPE ```

07a: The Eye Flashcards

(79 cards)