Cell Eyes

Front 1

All information from the photoreceptors in the retina is conducted by the ___________ to the brain.

Back 1

optic nerve

Front 2

Define accomodation.

Back 2

altering the shape of our lens so we are able to focus light as we look at varying distances

Front 3

What muscles are used for accomodation?

Back 3

Ciliary muscles within the ciliary body which are connected to the lens by suspensory ligaments

Front 4

What is the function of the iris?

Back 4

Gives eye color; adjusts the amount of light entering the body

Front 5

What is the function of the fovea centralis?

Back 5

used for fine vision

Front 6

What is found at the center of the fovea?

Back 6

Macula - it is weak and it degenerates easily -- called macular degeneration

Front 7

What is the eye from embryologically?

Back 7

the brain

Front 8

Describe the formation of the retina.

Back 8

1. The eye begins from part of the brain.

2. It invaginates and grows toward the surface ectoderm and forms a cup from neural tissue.

3. Differentiates into a pigmented layer and neural layer.

4. The 2 layers will contact either other causing the liquid space in between to disappear.

Front 9

Describe the formation of the lens.

Back 9

The surface ectoderm starts to invaginate which gives rise to the lens. THE LENS IS OF ECTODERMAL ORIGIN.

As it grows, it will become completely separated from the ectoderm.

Later in development we have the growth of the vessels called the HYALOID vessels into the eye all the way to the lens.

Front 10

What do the cornea and sclera develop from?

Back 10

Connective tissue under the epithelium.

Front 11

What does the neural layer give rise to?

Back 11

retina

Front 12

What does the pigmented layer give rise to?

Back 12

Retinal Pigmented Epithelium (RPE)

Front 13

Why can you have retinal detachment?

Back 13

The neural retins (retina) and the pigmented layer (retinal pigmented epithelium) fuse. This association; however, is relatively weak.

Front 14

How long does it take the eye to develop?

Back 14

After 2 months the eye is pretty much developed.

Front 15

The _____________ is very rich in blood vessels and is heavily pigmented.

Back 15

choroid.

Front 16

The cells of the lens are differentiating into ______________ .

Back 16

Primary lens fibers. The other cells will die leaving us the primary lens which we will have throughout life.

Front 17

(T/F) The lens continues to grow throughout life.

Back 17

True

Front 18

Which structures in the eye are avascular?

Back 18

retina (has a little vasculatization), lens, vitreous, and the cornea

if there is too much vascularization, it will affect vision.

Front 19

(T/F) Because the eye develops so fast, the vitreous caivty has to be vascularized to support this, but those vessels must later be removed.

Back 19

True

Front 20

What are the 3 layers of the eye?

Back 20

1. outer -- cornea, sclera, limbus.

2. choroid

3. retinal layer - nervous tissue (from nervous ectoderm)

Front 21

What is the limbus?

Back 21

transition region between cornea out in front and sclera in the back and towards the side

Front 22

What is the choroid?

Back 22

Contains the blood vessels and also have the ciliary body as an extension of it.

Front 23

Where does the iris come from?

Back 23

LAter in development, the iris comes from the choroid.

Front 24

What is the ora serrata?

Back 24

The retinal layer does not go all the way up to the ciliary body. There is a gap between called the ora serrata. This is where surgeons can enter without touching the retina.

Front 25

Describe the cornea.

Back 25

It must allow passage of light. Covered with epithelium which rests on the basal lamina and a very thick basement membrane called Bowman's layer.

The stroma contains very dense collagen.

Descement's layer - another BM like structure

The cornea is not vascularized -- it suppresses the growth of blood vessels

Front 26

Which structure is more highly organized: cornea or sclera?

Back 26

cornea - highly organized collagen fibers.

sclera - much more random collagen fibers.

Front 27

Does the cornea have nerves?

Back 27

Yes, it has nerves that go into the epithelium. It is very painful if you scratch.

Front 28

What is being done in the Lasik procedure?

Back 28

Use of a laser to reshape the cornea.

Front 29

What holds the lens in place?

Back 29

filaments/suspensory ligaments hold the lens in place. They contain fibrillin.

Have lens dislocation in Marfan syndrome because fibrillin is the location of the mutation.

Front 30

What is the sequence of events so you can see objects that are close?

Back 30

1. ciliary muscle contracts
2. tension is reduced.
3. lens rounds to see close objects.

Front 31

What is the sequence of events so we can see objects that are far?

Back 31

1. Ciliary muscle is relaxed.
2. tension increases.
3. lens flattens so we can see things far away.

Front 32

There is movement of liquid in the eye. Where is this liquid made and what tract does it follow during its flow.

Back 32

The liquid is made by the ciliary body. It travels between the lens and the iris and comes into the anterior chamber. It leaves the eye by going through a filter called the trebecular meshwork via the Canal of Schlemm into the aqueous veins.

Front 33

What happens in the trabecular meshwork of the Canal of Schlemm gets blocked?

Back 33

Glaucoma and this pressure can also damage the function of the optic nerve.

Front 34

What are the epithelium layers of the ciliary boddy. Where does secretion of the liquid originate?

Back 34

2 layers:
1. Outer non-pigmented
2. inner pigmented

Secretion occurs from the non-pigmented layer

Front 35

What is the iris?

Back 35

Part of the iris is heavily pigmented and the epithelium that is continuous with the epithelium ciliary body is full of pigmented granules.

Front 36

What determines the size of the pupil?

Back 36

The dilator muscle runs under the pigmented layer and then below that is the constrictor muscles. These determine the size of the pupil.

Front 37

Describe the development of the lens in regards to the lens fiber cells.

Back 37

The lens is of epithelium origin and has no blood vessels. It is a single layer of epithelium cells that elongate to give the lens fiber cells. The cells in teh center will die during development during development leaving just the outer elongated cells.
Contains specific proteins called CRYSTALLINS

Front 38

Describe the ADULT lens.

Back 38

Single layer of simple cuboidal epithelium and there is a BM on the outer surface called the lens capsule (very tough)

In the inner lens which are now just remnants of the lens fibers. These fibers are full of the protein crystallin.

There are no blood vessels and no CT except for the BM containing type 4 and laminin.