Eye Flashcards
1
Q
Normal tear menisucs is _mm above eyelid margin
A
1mm
2
Q
Which has a lower refractve index air or tear film
A
air
3
Q
what are the 2 layers of tear film
A
lipid layer over mucoaqueous phase
4
Q
Tear film thickeness ___um
A
3.4um
5
Q
steady state volume of tears is
A
7.4uL
6
Q
Name 2 glands part o f the accessory lacrimal gland
A
Glands of Krause
Glands of Wolfring
7
Q
Which ions regulate osmotic flow
A
Na, K, Cl
8
Q
Which ion regulated tear pH
A
Bicarbonate
9
Q
Most common immunoglobulin in the tear film
A
IgA
10
Q
Corneal avascularity is maintained by
A
VEGF receptor 1 . Blocks VEGF A
11
Q
Oxygen supply to cornea via
A
precorneal tear film
12
Q
Primary metabolic substrate of cornea is
A
Glucose
13
Q
Can Bowman’s layer regenerate
A
No
14
Q
Why does LASEK cause central haze compared to LASIK
A
LASEK Bowman layer is removed whereas in LASIK bowman layer transected by retained
15
Q
Stoma makes up _% corneal thickness
A
90%
16
Q
Major type of collagen in stroma
A
Type I
17
Q
Which collagen type associated with stromal healing
A
Tpye III
18
Q
AFter collagen____ are second most abundant biological constintuent in corena
A
Proteoglycans
19
Q
Most abundant collagen in Descemet membrane
A
Type IV
20
Q
aqeous humour is secreted by
A
Non pigmented ciliary epithelium
21
Q
Aqueous humour has high or low protein content
A
low
22
Q
Aqueous humour has high or low acorbate content
A
high
23
Q
refractive index of aqueous humour
A
1.336
24
Q
Lens refractive index
A
1.390
25
Lens relies on ____ for ATP production
glycolysis
26
What gives the lens a high refractive index
High amount of porteins suchs as crystallins
27
Main collagen type in lens capsule
Type IV
28
Which part of lens capsule is thicker anterior or posterior
anterior
29
Wavelenghth shorter than 400nm is referred to as
UV light
30
Wavelenghths lower than 30nm is blocked by which parts of the eye (2)
cornea and ascorbate
31
Vitreous makes up __ % volume of the eye
80
32
Stickler syndrom is due to mutation in gene COL2A1 which codes for_____
Type II collagen
33
which part of the eye has highest rate of oxygen comsumption
retinaa
34
light induces ________ , leading to cascade of reaction in the ______ outer segments called _______ which convertes light energy into electrical enegy
hyperpolarisation, photoreception, phototransduction
35
which are more sensitive to light, rods or cones?
rods
36
Two laminar structures line the back of the eye _____ and ____
RPE and neural retina
37
name the 3 glial cells in the retina
Muller, astrocytes, microglia
38
rods are highly sensitive and can be activated by a ____ photon and have a ____ surface area compared to cones
single, wider surface area
39
Cones are _____ sensitive than rods but can adapt to a wider range of light intensities and respond more rapidly to ____ stimulation
less, repetitive
40
In rod outersegments, there are roughly ____ discs and __________ membrane bound rhodopsin molcules in each disc
1000 discs
1 million rhodopsin molecules
41
rhodopsin in insensitive to ______ light
red light
42
rhodopsin ins embedded in the ____ membrane of outer segment
lipid membrane
43
in dark responses of rod:
rhodopsin is active or inactive?
Na channels open or closed
the rod is in a depolarised or hyperpolarised state?
glutamate released or not at synpatic cleft to bipolar cell?
bipolar cell hyperpolarised or depolarised
inactive
open
depolarised
glutatmate released
hyperpolarised
44
In light responses:
rhodopsin is active or inactive?
Na channels open or closed
the rod is in a depolarised or hyperpolarised state?
glutamate released or not at synpatic cleft to bipolar cell?
bipolar cell hyperpolarised or depolarised
active
closed
hyperpolarised
glutamate not released
bipola cell depolarised
45
S cones, short wavelength sensitive cones create what colour. vision
blue yellow
46
Middle waveleghth sensitive cones detect what type of colour
black white high resolution achromatic contrast
47
L cones create what colour vision
red green
48
what is the most common RHO mutation in RP
P23H
49
What are the 3 main cells involved in information flow from photoreceptor to optic vernce
Photoreceptor -> bipolar->ganglion
50
mutation of which gene leads to Leber congential amaurosis
RPE 65
51
RPE is a monolayer of epithelial cells that lie between _____ and _____
choriocapilliaris and photoreceptor outersegments
52
how many RPE cells per eye
4-6million
53
RPE cells are joined on the apical side by ___ ____
tight junctions
54
where are pigment granules in RPE cells
cytoplasm
55
this visual cycle is the conversion of ______ to _______ _______
11 cist retinal to all trans retinal to all trans retinol
56
this isemoersation of 11 cis retinal to all trans retinal is known as
bleaching
57
Phototransduction occurs where in the photoreceptor
photoreeptor outer segments
58
Int he visual pathway what is the first order neurone and second order neurone
first - photoreceptor ( rod or cone)
second - bipolar cell which synapses with ganglion cell
59
What are the 2 populations of ganglion cells and their function
parvocellular - fine VA and colour
Magnocellular - motion detection and coarser vision
60
At the optic chaism _____ fibres cross and _____ fibres remain uncrossed
nasal
temporal
61
THe optic tracts progress to the _________ on the ______________
lateral geniculate nucleus
posterior surface of the thalamus
62
In the LGN crossed fibres terminate to
Lamniae 1,4,6
63
In the LGN uncrossed fibres terminate to
Laminae 2,3,5
64
in the LGN ganglion cell fibres synapse with cells that connect via optic radiations to _______ area____
occipital cortex area 17
65
IN utero, at how many weeks do the edges of the optic stalk seal near the forebrain
5-6 weeks
66
What is the name of the remnant of glial cells and posterior hyaloid vessels that may persist at the optic nerve head
Bergmeister's papilla
67
WHat is the anterior remnant of hyaloid vessels on the posterior lens capsule
Mittendorf's dot
68
When are optic nerve fibres maximal
in utero, decrease before birth
69
How many ganglion cells axons are there
1.2 million
70
At what point do ganglion cell acons become myelinated
once exited lamina cribosa
71
lenghth of optic nerve
40mm
72
what is the role of microglial cells
resident macrophages
73
what is the role of astrocytes
structural support and regulate potassium
74
what is the role of oligodendrocytes
myelination
75
diameter of optic disc
1.5mm
76
How long optic nerve orbital portion
25mm
77
Ciliary ganglion lies between ____ and______
optic nerve and lateral rectus
78
How long intracanalicular portion of optic nerve
5mm
79
dimensions of optic chiasm
12mm x 8mm
80
Which fibress pass in the anterior and inferior chiasm
inferior nasal fibres
81
which fibres pass in the posterior and superior chiasm
superior nasal
82
If a bitemporal hemianopia is superioirly dense where is the compression
inferior compression e.g. pit adenoma
83
If a bitemporal hemianopia is inferiorly dense where is the compression
superior compression e.g craniopharnygioma
84
Pretectal nucleus is reponsible for
pupillary light reflexes
85
Suprachiasmatic nucleus responsbile for
circadian rhythm
86
Pulvinar nucleus responsible for
Visual attention and motor integration
87
Parvocellular reticular formation responsible for
arousal
88
Blood supply of optic tract
Posterior communicating artery
Pial arteries
89
From pretectal nuclues fibres pass to _____ nuclei
Edinger Westphal nuclei
90
From EW nuclei parasympathetic fibres travel in the _______ to the ________
oculomotor nerve to the ciliary ganglion
91
From EW nuclei postganglionic fibres travel in the _______ to the ________
short ciliary nerves to the constrictor pupillae
92
In the lateral geniculate nucleus, layers 1 and 2 receive data from
peripheral retina vai magnocellular pathway
93
In the lateral geniculate nucleus, layers 3-6 receive data from
fovea via parvocellular pathway
94
where do optic radiations terminate
striate visual cortex area 17
95
Are parvocellular fibres fast or slow fibres
slow fibres
96
magnocellular fibres are fast or slow fibres
fast fibres
97
parvocellular fibres go to which layers of LGN
layers 3-6
98
magnoceullular fibres go to which laters of LGN
layers1-2
99
conjunctiva emryologically derived from?
surface ectoderm
100
name the 2 accessory lacrimal glands
Krausse and Wolfring
101
Where is Gland of Krause
superioir fornix
102
Where is Gland of Wolfring
superior tarsal border
103
the accessory glands provide ____ tear production
basal
104
conjunctival sac has ___ microlitre capacity
25-30
