Ophthalmology Anatomy Flashcards
1
Q
what is covered by the cornea?
A
iris
2
Q
what are visible the blood vessels in the eyes called?
A
conjunctival vessels
3
Q
where does the lacrimal fluid collect?
A
lacrimal lake
4
Q
what are the small holes in the eyelids?
A
lacrimal punctum
5
Q
what is the raised part of the eyelid that the punctum are on?
A
lacrimal papilla
6
Q
junction between bulbar and palpebral conjunctiva
A
conjunctival cortex
7
Q
what is lined by the conjunctiva?
A
sclera
8
Q
what is the name of the corneoscleral junction?
A
limbus
9
Q
where is the lacrimal gland located?
A
superolaterally
10
Q
where is the nasolacrimal duct located?
A
inferomedially
11
Q
three layers of eye
A
outer fibrous, middle vascular (uvea), inner retina (photosensitive)
12
Q
two parts of outer fibrous layer
A
sclera and cornea
13
Q
function of sclera
A
muscle attachment
14
Q
function of cornea
A
2/3 of refractive power
15
Q
three parts of uvea
A
iris, ciliary body, choroid
16
Q
function of iris
A
control pupil diameter
17
Q
function of ciliary body
A
controls iris, shape of lens, secretion of aqueous humour
18
Q
function of choroid
A
nutrition and gas exchange
19
Q
what does anterior segment contain?
A
aqueous humour
20
Q
what is the anterior segment divided into?
A
anterior and posterior chambers
21
Q
2 facts about posterior segment
A
posterior 2/3 of the eye, behind lens
22
Q
what does the posterior segment of the eye secrete?
A
vitreous humour
23
Q
what is the vitreous body?
A
made up of vitreous humour
24
Q
path of aqueous humour
A
ciliary body –> posterior chamber –> anterior chamber –> canal of Schlemm –> venous system
25
what controls the release of aqueous humour into the venous system?
iridocorneal angle
26
artery that supplies the eye
ophthalmic artery
27
nerve that supplies the eye
optic nerve (CNII)
28
2 important branches of ophthalmic artery
forehead (scalp) branches and ciliary branches
29
what 3 veins does the orbit drain into?
superior ophthalmic vein, inferior ophthalmic vein, facial vein (anteriorly)
30
components of fundus
optic disc, macula, fovea,
31
function of fundus
posterior area where light is focussed
32
3 functions of optic disc
point of CNII formation, only point of entry/exit for blood vessels and axons of CNII, blind spot
33
what does the macula contain?
greatest density of cones
34
2 facts about fovea
1.5mm diameter depression, area of most acute vision
35
where is the fovea located?
centre of macula
36
3 layers of retina
photoreceptors, ganglion cells, axons of ganglion cells
37
are there photoreceptors in the optic disc?
no
38
features of fundoscopy
optic disc, central artery and vein of retina, nasal retina, temporal retina, branches of retinal vessels, macula of retina
39
where is light from objects in the left visual field processed?
right visual cortex
40
where is light from objects in the right visual field processed?
left visual cortex
41
transverse axis of eye movement
abduction/adduction
42
vertical axis of eye movement
elevation/depression
43
anteroposterior axis of eye movement
intorsion/extorsion
44
movement of lateral rectus
abduction of eyeball
45
nerve supply of lateral rectus
CNVI
46
movement of medial rectus
adduction of eyeball
47
nerve supply of medial rectus
CNIII
48
movement of superior oblique
depression of eyeball in adduction
49
nerve supply of superior oblique
CNIV
50
movement of inferior oblique
elevation of eyeball in adduction
51
nerve supply of inferior oblique
CNIII
52
movement of superior rectus
elevation of eyeball in abduction
53
nerve supply of superior rectus
CNIII
54
movement of inferior rectus
depression of eyeball in abduction
55
nerve supply of inferior rectus
CNIII
56
7 bones that make up the orbit
frontal, lacrimal, ethmoid, maxilla, zygomatic, sphenoid, palatine
57
is the apex of the orbital pyramid anterior or posterior?
posterior
58
is the base of the orbital pyramid anterior or posterior?
anterior
59
what are the 4 margins of the base of the orbital pyramid?
lateral, medial, superior, inferior
60
axis of orbit
anterolateral
61
axis of eyeball
anterior
62
blowout fractures involve...
medial wall and orbital floor
63
where is the outside of the orbit most likely to fracture?
suture
64
two parts of orbicularis oculi
palpebral and orbital
65
function of orbital part of orbicularis oculi
forced closing of the eye
66
function of palpebral part of orbicularis oculi
blinking
67
nerve supply of orbicularis oculi
CNVII
68
6 ligaments of eyelids
lateral palpebral, medial palpebral, superior tarsus, inferior tarsus, tendon of LPS, orbital septum
69
superior tarsus muscle aka
Mueller's muscle
70
tarsal glands aka
Meibomian glands
71
function of Meibomian glands
lipid secretion
72
innervation of the lacrimal gland
CNVII (parasympathetic)
73
where does lacrimal fluid collect?
lacrimal lake
74
where does lacrimal fluid drain?
lacrimal puncta
75
where does lacrimal fluid go after draining through the lacrimal puncta?
lacrimal sac and nasolacrimal duct
76
insertion of rectus and oblique muscles
sclera
77
origin of rectus muscles
common tendinous ring
78
origin of oblique muscles
sphenoid bone
79
origin of LPS
lesser wing of sphenoid
80
insertion of LPS
skin and tarsus of superior eyelid
81
afferent nerve involved in blink reflex
CNV1
82
efferent nerve involved in blink reflex
CNVII
83
oculocardiac reflex
reflex bradycardia in response to tension on extraocular muscles or pressure on eyes
84
4 sympathetic reflexes of the eye
open eyes wider, pupillary dilatation, emotional lacrimation, focus on far objects
85
3 parasympathetic reflexes of the eye
pupillary constriction, reflex lacrimation, focus on near objects
86
innervation of LPS
CNIII (sympathetic)
87
muscle that constricts pupil
sphincter pupillae
88
muscle that dilates pupil
dilator pupillae
89
sphincter pupillae fibres encircle...
internal circumference of iris
90
origin of dilator pupillae
external circumference of iris
91
insertion of dilator pupillae
internal circumference of iris
92
which end of dilator pupillae is mobile?
internal circumference of iris
93
non-physiologically enlarged pupil
mydriatic pupil
94
non-physiologically constricted pupil
miotic pupil
95
fixed-dilated/blown pupil indicates...
CNIII pathology
96
fixed pin-point pupil indicates...
opiate drugs
97
sensory component of pupillary light reflex
ipsilateral CNII
98
motor component of pupillary light reflex
bilateral CNIII
99
light reflex in stimulated eye
direct
100
light reflex in non-stimulated eye
consensual
101
3 steps of first neurones in light reflex
1. retinal ganglion cells pass via ipsilateral optic nerve
2. decussate in optic chiasm
3. synapse in pretectal nucleus in midbrain
102
path of second neurones in light reflex
pretectal nucleus to Edinger-Westphal nucleus
103
path of third neurones in light reflex
Edinger-Westphal nucleus via CNIII (inferior division) to synapse in ciliary ganglion
104
path of fourth neurones in light reflex
supply sphincter pupillae muscles via short ciliary nerves
105
what does ciliary muscle do in far vision?
relaxes
106
what does ciliary muscle do in near vision
contracts
107
innervation of ciliary muscle
CNIII
108
three types of tears
basal, reflex, emotional
109
basal tears
corneal health, clean, nourish and hydrate avascular cornea, contain lysozymes to hydrolyse bacterial walls
110
reflex tears
extra tears in response to mechanical or chemical stimulation
111
afferent nerve of reflex tears
CNV1 (from cornea/conjunctiva)
112
efferent nerve of reflex tears
CNVII (parasympathetic)
113
branch of CNVII that carries parasympathetic axons to lacrimal gland
greater petrosal nerve
114
3 steps of route of presynaptic sympathetic axons from CNS to head and neck
1. exit spinal cord at T1
2. ascend within sympathetic chain
3. synapse in superior cervical ganglion
115
4 steps of route of postsynaptic sympathetic axons from CNS to head and neck
1. enter external and internal carotid nerves
2. pass onto surface of external and internal carotid arteries
3. carried to organs of head and neck from branches of these arteries
4. ophthalmic artery carries axons to the orbit
116
what do the parasympathetic ganglia in the head supply?
eye, lacrimal gland, salivary glands
117
what does the vagus nerve supply?
organs of neck, chest and abdomen as far as midgut
118
what do the sacral spinal nerves supply?
hindgut, pelvis, perineum
119
do parasympathetic fibres synapse in the ciliary ganglion?
yes
120
do sympathetic fibres synapse in the ciliary ganglion?
no
121
where is the ciliary ganglion located?
bony orbit
122
what fibres contribute to the ciliary ganglion?
CNIII
123
where does CNIII connect with CNS?
junction of midbrain and pons
124
what sinus does CNIII pass through?
cavernous sinus
125
what does CNIII supply?
somatic motor to majority of extraocular muscles, presynaptic parasympathetic axons to ciliary ganglion
126
2 divisions of CNIII
superior and inferior
127
4 layers of meninges
dura mater, arachnoid mater, subarachnoid space, pia mater
128
sensory supply of dura mater
CNV
129
function of dura mater
encloses venous sinuses
130
what does arachnoid mater contain?
arachnoid granulations
131
what is in the subarachnoid space?
circulating CSF and blood vessels
132
what does pia mater adhere to?
brain and entering/leaving vessels/nerves
133
how to access CSF
lumbar puncture at L3/4/5 IV disc levels
134
where does subarachnoid space end inferiorly?
L2
135
what does the subarachnoid space communicate with at specific areas in the brain?
ventricles
136
6 ventricles of the brain
right lateral, left lateral, midline 3rd, midline 4th, cerebral aqueduct, central canal
137
8 steps of CSF circulation
1. secreted by choroid plexus
2. through right and left lateral ventricles
3. through midline 3rd ventricle
4. through cerebral aqueduct
5. through midline 4th ventricle
6. mainly into subarachnoid space, but some into central canal
7. reabsorbed in arachnoid granulations
8. into dural venous sinuses
138
function of arachnoid granulations
reabsorb CSF
139
Monro-Kellie hypothesis
if one structure in the brain increases in volume, the others must decrease in volume to compensate
140
what percentage of patients with ICP report visual problems?
65-75%
141
at what ICP is intervention required?
>20mmHg
142
optic discs specifically due to raised ICP
papilloedema
143
what can brain herniate through in raised ICP?
dural septae
144
4 sections of cranial cavity created by dural septae
falx cerebri, falx cerebelli, diaphragma sellae, tentorium cerebelli
145
what nerve is damaged in a 'down and out' eye?
CNIII
146
what nerve is damaged if the eye cannot move inferomedially?
CNIV
147
what nerve is damaged in medial deviation of the eye?
CNVI
148
which component of the blood-ocular barrier is located in the anterior segment of the eye?
blood-aqueous barrier
149
which component of the blood-ocular barrier is located in the posterior segment of the eye?
blood-retinal barrier
150
is epithelium hydrophilic or hydrophobic?
hydrophobic/lipophilic
151
is stroma hydrophilic or hydrophobic?
hydrophilic/lipophobic
152
3 major functions of CSF
mechanical protection, homeostatic function, circulation
153
specialised cells that secrete CSF
choroidal cells
154
networks of capillaries in the walls of brain ventricles
choroid plexus
155
what ions are transported in CSF secretion?
sodium, chloride, bicarbonate
156
does CSF secretion depend on other external factors?
no
157
where does CSF return to venous circulation?
superior sagittal sinus (SSS)
158
how does CSF get into SSS?
arachnoid granulations
159
what restricts the blood supply to the brain?
blood-brain barrier (BBB)
160
what is the site of the BBB?
endothelial cells of capillaries
161
3 components of BBB
capillary endothelium, basal membrane, perivascular astrocytes
162
2 parts of the brain that don't have a BBB
circumventricular organs, pineal gland
163
3 types of tumours of choroid plexus, CSF and ventricles
colloid cyst, ependymomas, choroid plexus tumours
164
3 types of ventricular haemorrhages
epidural haematoma, subdural haematoma, subarachnoid haematoma
165
where is aqueous humour produced?
ciliary body
166
what vitamin is a powerful antioxidant in the eyes?
vitamin C (ascorbate)
167
two layers of ciliary epithelium
pigment epithelium of retina (PE), nonpigmented epithelium (NPE)
168
what ions have a net movement through PE and NPE during aqueous humour production?
Cl- and Na+
169
what drugs can be used to block production of aqueous humour?
carbonic anhydrase (CA) inhibitors
170
name 2 CA inhibitors
dorzolamide and acetazolamide
171
what is the scope of the visual field
150 degrees
172
hemiretina from fovea to nose
nasal hemiretina
173
hemiretina from fovea to temporal bone
temporal hemiretina
174
Hebb's postulate
when an axon of cell A is near enough to excite cell B on a regular basis, its efficiency to excite cell B increases
175
3 steps in pathway for signal transmission
photoreceptors --> bipolar cells --> ganglion cells
176
receive input from photoreceptors and project to other photoreceptors and bipolar cells
horizontal cells
177
receive input from bipolar cells and project to ganglion cells, bipolar cells and other cells of their own type
amacrine cells
178
conversion of electromagnetic radiation to neural signals
transduction
179
4 regions of a photoreceptor cell
outer segment, inner segment, cell body, synaptic terminal
180
glutamate level in low light levels in dark current channel
higher
181
glutamate level in high light levels in dark current channel
lower
182
resting membrane potential of a photoreceptor
~-20mV
183
potential of sodium and potassium in the dark
equal
184
potential of sodium and potassium in response to light
potassium is higher
185
2 components of rhodopsin
retinal + opsin
186
what is retinal?
vitamin A derivative
187
what is opsin?
G-protein coupled receptor
188
what does light to do rhodopsin?
converts 11-cis-retinal to all-trans-retinal
189
4 steps to molecular mechanism of eyes
1. rhodopsin activates transducin
2. transducin activates phosphodiesterase
3. phosphodiesterase hydrolyses cGMP
4. reduced concentration of cGMP leads to closure of sodium channels
190
what is the high gain mechanism?
1 opsin activates 1000 transducin
1 PDE hydrolyses 1000 cGMP
191
which photoreceptor is associated with dark current channels?
rods
192
which photoreceptor is associated with light current channel?
cones
193
glutamate level in high light levels in light current channel
higher
194
glutamate level in low light levels in light current channel
lower
195
the ability to distinguish between two nearby points
visual acuity
196
what determines visual acuity?
photoreceptor spacing
197
which type of photoreceptor is concentrated at the fovea?
cones
198
where are rods distributed?
all over the eye
199
which type of photoreceptor has high convergence?
rods
200
which type of photoreceptor has low convergence?
cones
201
which type of photoreceptor has high light sensitivity?
rods
202
which type of photoreceptor has low light sensitivity?
cones
203
which type of photoreceptor has low visual acuity?
rods
204
which type of photoreceptor has high visual acuity?
cones
