Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Ocular Physiology > Function of the Iris > Flashcards

Function of the Iris Flashcards

1
Q

Cornea _______ the iris

A

magnifies

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Diameter of Iris

A

12mm

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Thickness of Iris

A

500 microns at thinnest point

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Abnormally decentered pupil

A

ectopic

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

Posterior portion of iris originates from….

A

neuroepithelium

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Parts of posterior portion of iris

A

dilator m
sphincter m
post pigmented epithelium

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Anterior Portion of iris originates from…..

A

mesoderm

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Parts of anterior portion of iris

A

iris stroma
iris vessels
iris nerves
chromatophores

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Optimal Pupil Size

A

2mm

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Functions of Iris

A

regulates retinal illumination, glare, optical aberrations, depth of focus
nonverbal communication and social signaling
attraction/ mate selection

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Miosis

A

Constriction

pupillary portion pleats, ciliary portion smooths out

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

Mydriasis

A

Dilation

stroma in pupillary portion goes flat, ciliary portion pleats

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

T/F Stroma and iris are elastic

A

false

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Iris Stroma

A

thickest part

made of collagen

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Function of Stroma

A

anchor for sphincter m, nerves and vessels

protects nerves and vessels from stretching and kinking

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Anterior Border Layer

A

pigment- melanocytes

thicker in darker eyes

17
Q

Iris Vessels come from….

A

ophthalmic artery- long post ciliary aa + ant ciliary arteries (next to rectus mm)

18
Q

T/F Iris does not bleed when cut

A

T

19
Q

Myopes/ Hyperopes have larger pupils?

A

myopes

greater corneal power and deeper anterior chambers

20
Q

Affects vision if pupil size is smaller than 2 mm

A

diffraction limit

reduced illumination

21
Q

Pupil size ______ with age

A

decreases

22
Q

Near Vision Triad

A

convergence, miosis, accommodation

23
Q

Iris sphincter and dilator originate….

A

neural ectoderm

24
Q

Iris Sphincter innervated by…

A

parasympathetic

25
Q

Iris Dilator innervated by…

A

sympathetic

26
Q

Which iris muscle is stronger?

A

they are equal

27
Q

Iris and Aging

A

no change to dilator m or light reflex

pupil size reduced

28
Q

Horner’s Pupil

A

dilates less than normal when given cocaine

29
Q

Cocaine

A

blocks reuptake of post-ganglionic NE causing dilation

30
Q

Apraclonidine

A

increased mydriasis in Horner eye

31
Q

Part of iris absorbing heat

A

pigment of posterior iris

causes sphincter to contract- possible iritis w/ miosis

Ocular Physiology (5 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions