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Flashcards in B10 Deck (242)
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1

The pupil that is seen is actually a _____ image of the ____ pupil

Magnified virtual image of the real object pupil

2

Name the 7 functions of the iris

-improve visual clarity (regulates optical aberrations
-attraction/mate selection
-non verbal communication
-reduce glare
-control illumination
-prevent dazzling
-increase the depth of focus

3

The iris separates the

Anterior and posterior chambers of the eye

4

The iris is surrounded by what fluid?

Aqueous

5

T/f: the iris is the most anterior portion of the uveal tract

True

6

The iris rests lightly upon the ___

Lens

7

What is the average diameter of the iris?

12mm

8

The pupil center is slightly __ and ___ to the iris center

Slightly nasal and inferior

9

An abnormally decentered pupil

Ectopic

10

What does irregular or ectopic pupils do to optical quality

They degrade it

11

The pupillary margin rests on the ___ surface of the lens

Anterior

12

How does aqueous humor flow

It flows from the posterior-->anterior through the pupil

13

T/F: Temporal iris in humans broader than nasal iris

True

14

The posterior portion of the iris is derived from?

Neuroectoderm/neuroepithelium

15

The dilator muscle is derived from the

Neuroepithelium

16

The sphincter muscle is derived from the

Neuroepithelium

17

The posterior pigmented epithelium is derived from the

Neuroepithelium

18

The anterior portion of the iris is derived from

Mesoderm

19

The iris stroma is derived from

Mesoderm

20

The iris vessels is derived from

Mesoderm

21

The iris nerves are derived from

Mesoderm

22

The chromatophores are derived from

Mesoderm

23

What are the 4 layers of the iris?

-anterior border layer
-stroma and sphincter muscle
-anterior epithelium and dilator muscle
-posterior epithelium

24

What layer contains both mesoderm and ectoderm

Stroma and sphincter muscle

25

The reduction in optical aberrations and depth of focus is optimal at

2mm or less

26

What are the only elements in the iris that is capable of initiating movement

Iris muscles

27

What occurs in miosis (constriction if pupils)

the pupillary portion of iris gathers into pleats while the ciliary portion smooths out.

28

What occurs in mydriasis (dilation)

the stroma in the pupillary zone pulls flat while
contraction furrows appear in the ciliary area.

29

T/F: blow flow is impeded by wither miosis or mydriasis

False. It is not impeded

30

T/F: in the past, it was believed that the stroma and blood vessels were responsible for iris movements, via elastic expansion, changes in hydration, and/or engorgement.

True