Med Neuro [Week 2]

Question 1

The cornea contributes between ________ of the eyes total focusing power.

Answer 1

65-75%

Question 2

True or false: The cornea has no blood vessels.

Answer 2

True

Question 3

From outside to inside, what are the 5 layers of the cornea?

Answer 3

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

Question 4

What is the function of the epithelium of the cornea? (2)

Answer 4

1. Protection from dust, water, and bacteria

2. Absorb oxygen and nutrients from tears and distribute them to the rest of the cornea.

Question 5

What part of the cornea will scar as it heals?

Answer 5

Bowmans membrane

Question 6

Stroma consists primarily of water and collagen and contributes ______ of the cornea’s thickness.

Answer 6

90%

Question 7

What is the function of Descemet’s membrane?

Answer 7

Barrier against infection and injury

Question 8

What is the function of the corneal endothelium?

Answer 8

1. Pump excess fluid out of the stroma

Question 9

Can corneal endothelial cells regenerate?

Answer 9

No. Too much damage can lead to corneal edema and blindness

Question 10

Myopia

Answer 10

Nearsightedness (eye too long)

Question 11

Hyperopia

Answer 11

Farsightedness (eye too short)

Question 12

What are the three parts of the uvea?

Answer 12

1. Choroid
2. Ciliary body
3. Iris

Question 13

What makes up the largest component of the uvea?

Answer 13

The choroid

Question 14

What are the three layers of the choroid?

Answer 14

1. Vessel layer - medium sized arteries and veins
2. Chorocapillary layer - capillaries arranged in one plane
3. Bruch’s membrane - thin amorphous hyaline membrane where the retinal pigmented epithelia rests

Question 15

What is the ciliary body?

Answer 15

An expansion of stroma of the choroid near the lens

Question 16

What are the functions of the ciliary body?

Answer 16

1. Accommodation
2. Aqueous humor production
3. Production and maintenance of lens zonules

Question 17

What is the function of the iris?

Answer 17

1. Cover the lens

2. Regulate amount of light reaching retina

Question 18

People with brown eyes have more ____________.

Answer 18

Eumelanin

Question 19

What two muscles are behind the iris and regulate its size?

Answer 19

Sphincter pupillae - parasym

Dilator pupillae - symp

Question 20

Aqueous humor is drained from the anterior chamber via the ________________. From here it passes into the _______________________ that drains to the venous system

Answer 20

1. Trabecular meshwork

2. Canal of Schlemm

Question 21

Anterior chamber

Answer 21

Anterior of iris. Contains the aqueous humor, is avascular. Is involved in maintaining intraocular pressure

Question 22

What is the most common form of glaucoma?

Answer 22

Open-angle or chronic glaucoma - due to an obstruction of the drainage system

Question 23

What are the functions of the lens?

Answer 23

1. Refractive functions

2. Accommodation - thinner on distant objects - relaxed ciliary muscles

Question 24

The vitreous body is nearly acellular, major macromolecules are ____________________ and ___________________.

Answer 24

1. Type 2 collagen

2. Hyaluronic acid

Question 25

Where do the two regions of the retina come from?

Answer 25

Different layers of the optic cup during development

Question 26

What are the two regions of the retina?

Answer 26

1. Neural/sensory retina

2. Retinal pigment epithelium

Question 27

What are major functions of the retinal pigment epithelium?

Answer 27

1. Absorbs scattered light
2. Transports nutrients and ions between photoreceptors and choriocapillaries
3. Reisomerization of all-trans retinal
4. Secretion of GF for maintenance and structural integrity of retina

Question 28

The retina has a dual blood supply from the __________________ and the ____________________.

Answer 28

1. Choriocapillaries - outer retina

2. Central retinal artery - inner retina

Question 29

What receives the greatest blood flow?

Answer 29

The choroid - maintenance of the outer retina.