Outer Fibrous & Middle Vascular Tunic Flashcards
(159 cards)
1
Q
T/F
THE EYE IS A Very complex and delicate organ consisting of many
tissues which protect optic nerve and photoreceptor cells
A
TRUE
2
Q
The eye is Located in the skull cavity and is surrounded by _____
muscle and _____ tissues
A
fibrous; lipoidal
3
Q
t/f
A normal human eye can see about 1 million different
colors
A
f; 10 million
4
Q
Cornea and sclera are connected by a ring called
A
limbus
5
Q
conveys signals of the eye to the brain
A
Optic nerve
6
Q
___________________ is the clear fluid contained in the anterior
and posterior chamber
A
Aqueous humor
7
Q
_________________ is the clear gel-like fluid in the vitreous
chamber
A
Vitreous humor
8
Q
3 main layer of the eyes
A
Outer fibrous tunic
Middle Vascular tunic
Inner Nervous tunic
9
Q
Covers the exposed part of the
globe, e.g. cornea (anterior to
the pupil), conjunctiva (anterior
to the sclera)
● Comes directly in contact with
the environment
● Protects eye from external environment
● Located anterior to the cornea
A
precorneal tear film
10
Q
lipid/oil layer is produced by
A
meibomian glans
11
Q
lipid/oil layer is secreted by
A
meibomian, zeis & moll glands
12
Q
The outermost, most superficial layer of the pre-corneal tear film
A
lipid layer
13
Q
PCTF
retard evaporation of aqueous
A
lipid layer
14
Q
PCTF
PREVENTS OVERFLOW OF TEARS
A
LIPID LAYER
15
Q
AQUEOUS LAYER OF PCTF IS PRODUCED BY
A
LACRIMAL GLAND
16
Q
PCTF
THICKES LAYER
A
AQUEOUS LAYER
17
Q
which layer of pctf nourishes cornea with oxygen?
A
aqueous layer
18
Q
aqueous layer of pctf has antibacterial function due to presence of
A
lysozyme
19
Q
Aqueous layer of PCTF allows passage of _______________________ after injury
A
leucocytes
20
Q
PCTF
Produced by goblet cells
A
mucin/mucoid layer
21
Q
PCTF
secreted by conjunctival goblet cells & gland of Manz
A
mucin layer
22
Q
PCTF
FUNCTIONS IN LUBRICATION
A
MUCIN LAYER
23
Q
PCTF
THINNEST
A
MUCIN LAYER
24
Q
Outermost layer of the eye containing cornea and sclera
A
Outer Fibrous Tunic
25
T/F
The cornea is 1/6 of the eye
T
26
T/F
the cornea has blood vessels
F
cornea is avascular
27
The first transparent medium where light passes through
cornea
28
The tissue in the cornea absorbs its nutrition and oxygen by ____
diffusion
29
Cornea is responsible for approximately ______ of focusing power of eye
70%
30
T/F
Gas-permeable contact lenses can be worn for longer periods than hard contact lenses
T
31
Describe the prolate shape of cornea
steeper center, flatter periphery
32
Refractive index of cornea
1.376
33
Dioptric power of cornea
43.25 D
34
Anterior anatomical section shape of cornea
Elliptical
35
Posterior/internal anatomical section shape of cornea
circular
36
Anterior Radius of Curvature of Central Cornea
7.8 mm
37
Posterior Radius of Curvature of Central Cornea
6.5mm
38
Vertical corneal dimension (measurement)
11mm
39
Horizontal corneal dimension (measurement)
12mm
40
3 factors for corneal transparency
1. Anatomical factors
2. Physical factors
3. Physiological factors
41
What factor of corneal transparency:
Epithelium is non-keratinized (nucleated living cells)
Anatomical Factor
42
What factor of corneal transparency:
Stromal lamellae are regularly arranged
Anatomical
43
What factor of corneal transparency:
Cornea is avascular
Anatomical
44
What factor of corneal transparency:
Refractive index of fibers and matrix is the same
Physcal factor
45
Physiological factor
State where the cornea is partially dehydrated for it to be transparent
Deturgescence
46
Layers of the cornea
Anterior Epithelium
Bowman's Membrane
Corneal Stroma
Descemet's Membrane
Endothelium
47
Layer of the cornea
50-90 μm
Anterior epithelium
48
Layer of the cornea
12 μm
Bowman's membrane
49
Layer of the cornea
500 μm
Corneal stroma
50
Anterior epithelium is made up of
Stratified squamous non-keratinized epithelium (5-6
layers containing nerve endings)
50
T/F
Descemet's membrane:
5 μm in adult & 2 μm in children
false
2 μm in adult & 5 μm in children
51
Layers of the cornea that regenerates
Anterior epithelium
Corneal Stroma
Descemet's membrane
52
Layers of the cornea that does not regenerate
Bowman's membrane
Endothelium
53
Where does regeneration of anterior epithelium occur?
limbus/limbal area
54
junction between cornea and sclera
limbus/limbal area
55
t/f
Anterior epithelium is hydrophilic to maintain transparency
F
Anterior epithelium is HYDROPHOBIC to maintain transparency
56
5-7 layers of cells of anterior epithelium regenerate every ____ days to prevent scar formation
7
57
Cells in the anterior epithelium
Wing cell layer
Epithelial cells
Basal cell layer
58
Outer 2-3 layers of anterior epithelium
epithelial cells
59
Middle 2-4 cell layer of anterior epithelium
wing cell layer
60
Flat with many microvilli & horizontal nuclei. Joined with desmosomes to prevent tears
from penetrating the cornea
epithelial cells
61
shape of wing cell layer
polyhedral
62
t/f
Wing cell layer has deep cells with round nuclei, becomes flatter as cells approach the surface of the
cornea
t
63
Wing cell layer is Joined together from base to apex by
desmosomes and _____________________________
zonula occludens
64
Cell in the anterior epithelium:
Tall and columnar cells that often show mitosis
basal cell layer
65
Lateral cell borders of basal cell layer are joined by
_____________________
desmosomes
66
basal cell layer is Joined to the basement membrane by
hemidesmosomes
67
Basement membrane is firmly attached to underlying Bowman zone by _________ filaments
irregular
68
After injury of basement membrane, attachments may take as long as _____________ to be
reestablished
6 weeks
69
This extracellular matrix of the cornea is secreted by basal cells and composed of type IV collagen and laminin
Basement membrane
70
Basemnt membrane is secreted by the
basal cell
71
Basement membrane is composed of __________________
type IV collagen and laminin
72
Minute spaces in between basal cells and disappear gradually towards the surface. This may be distended pathologically
lymph spaces
73
Cell junctions
Zonula occludens (tight junctions)
Zonula adherens (desmosomes)
Hemidesmosomes
74
Cell junction between wing cells. This encircle the cell & form a seal
which prevents small molecules to pass
zonula occludens
75
Zonula occludens is also known as
tight junctions
76
Cell junction between basal cells
Zonula adherens
77
Zonula adherens is also known as
desmosomes
78
Cell junction between basal cells and basement membrane
hemidesmosomes
79
layer of the cornea that is structure less, acellular hyaline stroma
bowman's membrane
80
Bowman's membrane is made up of _______ oriented collagen fibers
randomly
81
Bowman's membrane is resistant to trauma and infection. This layer regenerates.
1st statement is true, 2nd statement is false
2nd statement is true, 1st statement is false
both statements are true
both statements are false
1st statement is true, 2nd statement is false
Bowman's membrane is resistant to trauma and infection. This layer does not regenerate.
82
layer of cornea with 90% of corneal thickness
corneal stroma
83
Corneal stroma is also known as
substantia propia
84
corneal stroma has ____% water content
78%
85
Corneal stroma compose of lamellae of collagen fibrils arranged in a regular ________ (type I, III, V, VI)
lattice
86
Examples of wandering cells in corneal stroma
leukocyte
macrophages
87
Corneal nerves enter peripherally in a _______ pattern into the stroma
radial
88
Injury to this area will result in extreme pain from the swelling and stretching of those nerves
corneal stroma
89
what layer of the cornea
true membrane
descemet's membrane
90
Descemet's membrane is made up of type IV collagen fibers arranged in __________ pattern
hexagonal
91
Descemet's membrane is not resistant to infection & trauma. It does not regenerate after injury
1st statement is true, 2nd statement is false
2nd statement is true, 1st statement is false
both statements are true
both statements are false
both statements are false
Descemet's membrane is very resistant to infection & trauma. it regenerates readily after injury
92
T/F
Endothelium consists of a single layer of flattened/hexagonal cells
with large oval nuclei
T
93
Endothelium has apices of the cell are in direct contact with the aqueous humor with occasional ___________
microvilli
94
layer of the cornea where Cells are tightly bound together by desmosomes & tight junctions
endothelium
95
Responsible for deturgescence of corneal stroma
endothelium
96
Functions as permeable membrane to bring in oxygen via aqueous while transporting out fluid and
waste product
Endothelium
97
Not yet included as part of the layers. Anatomically found between corneal storma and descemet's membrane
Dua's layer
98
Opaque network of collagen (fibrous protein) and elastic
fibers
sclera
99
Sclera covers posterior ___ of the outer coat of the eye
5/6
100
SCLERA
Thickest in the region surrounding the _______.
optic nerve
101
sclera
Thinnest immediately in the insertions of the _________
recti muscles
102
Forms the white of the eye
sclera
103
Sclera is covered with:
episclera
fascia bulbi (tenon's capsule)
conjunctiva
104
Sclera is opaque white due to:
variable diameter of collagen fibers
irregular arrangement of collagen fibers
high water content
105
3 main functions of sclera
Protects
Maintains shape and exact position of diff parts of the optic system
Provides rigid insertion and serves as attachment sites for EOM
106
Give the color of sclera:
1. Children, scleral thinning
2. Old
3. high refractive power
1. bluish
2. yellowish
3. bluish
107
Sclera appears bluish in children due to the underlying ______ and the sclera not yet fully developed
choroid
108
appears bluish among people with high refractive power due to _____________________________________
stretching and continuous elongation
109
Sclera appears yellowish in the older population due to
___________
fatty deposits
110
Layers if the sclera
episclera
scleral stroma
lamina fusca
111
layer of the sclera
Moderately dense, vascular CT that merges with scleral stroma. The anterior portion has rich blood supply. Blood vessels are inconspicuous (not visible) except
when inflamed
Episclera
112
scleral inflammation wherein blood vessels are visible
scleritis
113
Layer of the sclera with bundles of typical collagen fibers (type I & III)
scleral stroma
114
Scleral stroma is white because the collagen fibers have:
1. Variable diameter
2. Irregular arrangement
3. High water content
4. With fibroblast and pigment cells
115
Layer of the sclera
- Innermost layer
- Formed mainly of elastic fibers & fine collagen fibers
- Brown color due to the melanocytes from the choroid
lamina fusca
116
lamina fusca is brown due to the ____________________ from the choroid
melanocytes
117
Middle layer of the eye. Consists of Choroid, ciliary body & iris
Middle vascular tunic
118
Highly pigmented coat lining the sclera
choroid
119
Structure connecting choroid & iris. Lined by the ciliary part of the retina
Ciliary body
120
Parts of the ciliary body
Pars plana
Pars plicata
121
Part of the ciliary body near the choroid
pars plana
122
part of the ciliary body: smooth ciliary ring
pars plana
123
part of the ciliary body: ridged crown
pars plicata
124
Ciliary body contains:
Ciliary muscle
Ciliary processes
125
Ciliary muscles comprises 2 sets of smooth muscle fibers which are
longitudinal fibers
Oblique fibers
126
smooth muscle fiber in the ciliary muscle that connect sclera to choroid
longitudinal fibers
127
smooth muscle fiber in the ciliary muscle that enter the base of ciliary processes
oblique fibers
128
smooth muscle fiber in the ciliary muscle Supplied by parasympathetic fibers by the way of ciliary nerves
oblique fibers
129
Contraction of oblique fibers makes ciliary body move _________
anteriorward
130
Ciliary processes are about a. _____in number. Arranged in a circle posterior to the b. _______
- Site of secretion of c. ____________
a. 70
b. iris
c. aqueous humor
131
Circular, pigmented diaphragm. Lies anterior to the lens in a coronal plane
iris
132
Iris has a pattern of radial striations that is unique from one
individual to another.
t/f
t
133
Iris is anchored ____________ to the ciliary body
peripherally
134
2 chambers divided by iris between cornea and lens
Anterior chamber
posterior chamber
135
Chamber bounded by cornea and iris
anterior chamber
136
chamber filled with aqueous humor
Anterior chamber and Posterior chamber
137
chamber bounded by iris, ciliary process, zonule, crystalline lens
posterior chamber
138
Parts of the iris
Collaterette
Stroma
SPhicter pupillae
Dilator pupillae
139
Anterior surface of the iris
collarette
140
Part of the iris
Normally contains melanin pigment
stroma
141
Color of eyes with low melanin amount
blue
142
COlor of eyes with high melanin amount
brown
143
Situated in the posterior part of the iris, near the
pupil
sphincter pupillae
144
what type of muscle does sphincter pupillae have?
smooth muscle
145
Sphincter pupillae is supplied by parasympathetic fibers by way of
short ciliary nerves
146
Contraction of sphincter pupillae muscle results in pupillary
constriction (miosis)
147
what drug is placed on the eye which annuls the action of ciliary muscle and sphincter pupillae
(both are under parasympathetic control)
atropine-like
148
Consists smooth muscle anterior to the pigmented epithelium on the posterior aspect of the iris, which constitutes iridial part of the retina
Dilator pupillae
149
Dilator pupillae is supplied by ____________ fibers
sympathetic
150
Contraction of dilator pupillae results in _____ of the pupil
dilation (mydriasis)
151
Sympathetic innervation arises as preganglionic nerves leaving the spinal cord in the upper 4 thoracic
_________
ventral roots
152
transmit the sympathetics to the gangliated chain and the preganglionic fibers enter and ascend the cervical sympathetic chain
White rami
153
Dilator pupillae
Sympathetic preganglionic fibers synapse in the
superior cervical ganglion
154
Nerve fibers in the dilator pupillae follow the _____________ and ___________ to reach the eye
internal carotid;
ophthalmic arteries
155
Congenital, radial defect of the iris
coloboma
156
What is the radial muscle of the iris?
dilator pupillae
157
What is the circular muscle of the iris?
iris sphincter
158
Accompanied with a small (meiotic) pupil and slight
drooping of the upper eyelid due to paralysis of the
superior tarsal muscle
horner's syndrome
