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Histology > Eyeball > Flashcards

Flashcards in Eyeball Deck (25):
1

Information about the external world is conveyed to the CNS from __

sensory receptors

2

What are the three concentric tunics of the eye?

-tough external layer (sclera and transparent cornea)
-middle vascular layer (choroid, ciliary body, and iris)
-inner sensory layer (retina)

3

The ____ communicates with the cerebrum through the posterior optic nerve

retina

4

___is a perfectly transparent biconvex structure held in place by a circular system of zonular fibers that attach to the ciliary body

lens

5

The ___surrounds a central opening the__

iris;pupil

6

The___chamber is between the cornea and the iris

anterior chamber

7

The___chamber is between the iris and the lens

posterior chamber

8

Step 1 of eye formation:
In the 4-week embryo epithelial ____ bulge bilaterally from the forebrain, then elongate as the optic stalks bearing optic cups

optic vesicles

9

Step 2 of eye formation:
Inductive interaction between optic cups and overlying surface ectoderm cause the latter to detach as the ____

intial hollow lens vesicles

10

Step 3 of eye formation:
The optic stalk develops as the ___

optic nerve

11

Step 3 of eye formation:
In the inferior groove called the___ encloses the HYALOID VESSELS that supply blood for the developing lens and optic cup

choroid fissure

12

Step 4 of eye formation:
In the ensuing weeks ___differentiates to form most of the tissue in the eye's two outer layers and the vitreous

head mesenchyme

13

Step 4 of eye formation: Ectoderm of the optic cup differentiates as the ___ and ___ form the corneal epithelium

retina and surface ectoderm

14

Step 4 of eye formation:
When the lens is fully formed, the __ and veins disappear leaving only the blood supply to the retina

Distal hyaloid artery

15

The fibrous external layer of the eye has two major regions __ and __

Posterior sclera and anterior cornea joined at the limbus

16

The white posterior five-sixths of the external layer of the eyeball (fibrous layer) is called the__

sclera

17

_____muscles move the eyes

extraocular muscles

18

The anteiror 1/6th of the fibrous layer of the eye is the___ and is the transparent and completely avascular layer

cornea

19

__supports eye shape, protects delicate internsal eye structures, extrinsic eye muscles attach here

Sclera

20

____Protects anterior surface of the eye, refracts incoming light

Cornea

21

___supplies nourishmnet to retina, pigment absorbs extraneous light

Choroid

22

___holds suspensory ligaments that attach to thelens and change the lens shape for far and near vision, epithelium secretes humor

Ciliary body

23

___controls pupil diameter and thus the amount of light entering the eye

Iris

24

___absorbs extraneous light, provides vitamin A for photoreceptor cells

Pigmented Layer

25

___detects incoming light rays; light rays are converted to nerve signals and transmitted to the brain

Neural Layer