Eye Anatomy Flashcards
1
Q
What are the parts of the fibrous coat of the eyeball?
A
Sclera & cornea
2
Q
What are the parts of the vascular coat of the eyeball?
A
Choroid
Ciliary body
Iris
3
Q
What are the parts of the sensory coat of the eyeball?
A
Retina
4
Q
What is the function of the sclera?
A
Gives attachments to the extrocular muscles
5
Q
How much of the fibrous coat does the sclera make up?
A
5/6th
opaque
6
Q
What is the function of the cornea?
A
Allows light to enter the eye
7
Q
How much of the fibrous coat does the cornea make up?
A
1/6th
Transparent
8
Q
What is the function of the choroid?
A
Supplies blood to outer layer of retina
9
Q
What is the function of ciliary bodies?
A
Produces Aqueous humor
Suspends the lens
10
Q
What is the function of the iris?
A
Controls the diameter of the pupil & therefore the amount of light entering the eye
11
Q
What is the function of the retina?
A
Has rods & cones which enable us to see
12
Q
Where is vitreous humor found?
A
Posterior segment
13
Q
Where is AH found?
A
Anterior segment
14
Q
What is the structure of the lens described as?
A
Biconvex crystalline structure that is suspended from the ciliary body by suspensory ligaments
15
Q
What is the function of the AH?
A
It maintains intraocular pressure
16
Q
What is the function of VH?
A
Cushions the retina
17
Q
What is the anterior segment further divided into?
A
Anterior & posterior chamber
18
Q
Where is the Anterior chamber found?
A
In front of the iris
19
Q
Where is the anterior segment found?
A
In front of the lens
20
Q
Where is the posterior chamber found?
A
Behind the iris
21
Q
Where is the posterior segment found?
A
Behind the lens
22
Q
At the angle of the anterior chamber where does AH drain?
A
Via trabecular meshwork into the Schlemms canal
23
Q
What are the names of the 3 entry/exit points in the bony orbit?
A
Optic foramen
Superior orbital fissure
Inferior orbital fissure
24
Q
Which paranasal sinuses is the orbit closely related to?
A
Maxillary
Frontal
Ethmoid
25
Which area of the orbit is the weakest?
Medial & inferior walls of the orbit
26
What cushions the eyeball in the orbit?
Periorbital fat
27
What is another name for the mucosa membrane on the inside of the eyelid?
Conjuntiva
28
What type of gland is associated with eyelashes?
Sebaceous gland
29
What muscle is responsible for elevating the eyelid?
Levator palpebrae superioris
30
What is the name of the hard plate found in the eye lid?
Tarsal plate
31
What is the name of the glands found in association with the tarsal plate in the eyelid which produce oily secretions?
Meibomian glands
32
What are the different areas of the conjuntiva called?
Palpebral conjunctiva
Ocular conjunctiva
Superior/ Inferior fornix
33
What does the ocular conjunctiva cover?
Sclera
34
Which nerve stimulates the lacrimal gland?
Facial nerve (parasympathetic)
35
Where do tears drain from the eyeball?
Via punctate in the medial side of eye into lacrimal sac
36
Where do tears drain from the lacrimal sac?
Nasolacrimal duct
37
Where does the nasolacrimal duct drain?
Inferior meatus
38
What do intrinsic muscles of the eye control?
Pupil diameter & regulate lens curvature
39
What do extra ocular muscles control?
The movement of the eyeball
40
What muscle constricts the iris? What innervation?
```
Constrictor pupillae (circular)
Parasympathetic - IIIn
```
41
What muscle dilates the iris? What innervation?
```
Dilator pupillae (radial)
Sympathetic nerves
```
42
What innervates the ciliary body muscles?
Parasympathetic (IIIn)
43
When the ciliary bodies are activated what happens to the structure of the lens? What is this called?
Thicker & rounded
Focus close up
Accomodatio
44
How many straight muscle (recti) are found in the eye orbit?
4 - SR, LR, MR, IR
45
How many oblique muscles are there?
2 - SO, IO
46
Where do the recti muscles arise/insert?
Apex of orbit from annular fibrous ring & insert anteriorly to sclera
47
Where does the SO arise/insert?
Roof of orbit & insert posteriorly to sclera
48
Where does the IO arise/insert?
Floor of orbit anteriorly & insert posteriorly
49
What nerve supplies the LR?
Abducent nerve (VI)
50
What nerve supplies the SO?
Trochlear nerve (IV)
51
What nerve supplies the IO
Oculomotor nerve (III)
52
Where do parasympathetic fibres carried by IIIn synapse?
Ciliary ganglion
53
Which nerve carries sensory information to the orbit?
Trigeminal nerve (V1 & 2)
54
Where dos the maxillary division of trigeminal exit onto the face?
Infraorbital foramen
55
What is the ophthalmic artery a branch of?
ICA
56
What branch of the ophthalmic artery travels within the optic nerve?
Central retinal artery
57
What is another name for the physiological blind spot?
Optic disc
58
What is the name of the area of retina which has a high density of cones?
Fovea centralis
59
What are the 4 divisions the retina is divided into?
Superonasal
Superotemporal
Inferonasal
Inferotemporal
60
Where do the superior & inferior ophthalmic veins drain into?
Cavernous sinus
61
Which germ layer do eyes originate?
Ectoderm (from neural tube)
62
Where do optic vesicles grow out from?
Diencephalic part of neural tube
63
What forms after the optic vesicle in embryonic development of eye?
Optic cup
64
What embryological layer forms the EOM?
Mesenchyme (mesoderm)
65
What epithelial layer is found at the cornea?
Stratified squamous non-keratinised epithelium
66
What is another name for the basement membrane at the corneal epithelium?
Bowman's membrane
67
What is the thickest layer in the cornea called?
Stroma
68
What is the stroma of the cornea composed of?
Regularly arranged collagen
69
How many histological layers are present at the cornea?
5
70
What factors contribute to the cornea being transparent?
Regularly arranged collagen fibres in stroma
No blood vessles
Endothelial layer has pump which keeps AH out
71
Why does the avascularity of the cornea contribute to effective corneal transplants?
Less risk of rejection
72
How many layers compose the retina?
10 layers
73
What is the 1st layer of the retina composed of?
Pigmented epithelium
74
What is the 2nd retinal layer composed of?
Rods & cones
75
What is lens opacification called?
Cataract
76
What are the functions of the tear film?
Keeps cornea moist
Washes away particles of foreign body
Has antibodies
Smooths outer layer of cornea for refraction
77
Clinically how can you visualise the tear film?
Staining with fluorescein
78
How many layers compose the tear film?
3
1: mucinous layer
2: aqueous layer
3: oily layer
79
Which muscles elevate/depress the eye when it is adducted?
Oblique muscles
80
Which muscles elevate/depress the eye when it is abducted?
SR/IR
81
What is the mnemonic used to remember EOM movements?
RADSIN
Recti adductors
Superior intortors
82
What are the actions of the SR?
Elevation
Adduction
Intorsion
83
What are the actions of the IR?
Depression
Adduction
Extorsion
84
What are the actions of the SO?
Depression
Abduction
Intorsion
85
What are the actions of the IO?
Elevation
Extorsion
Abduction
86
What is the clinical term for squint?
Strabismus
87
What is the name of a convergent squint?
Esotropia
88
What is the name of a divergent squint?
Exotropia
89
What is amblyopia?
A lazy eye caused as a result of squint left uncorrected leading to suppression of image
90
What are the functional consequences of a squint?
Amblyopia
| Diplopia
91
When there is an increase in illumination, what happens to the pupil?
Constricts via IIIn parasympathetic fibres
92
When there is an decrease in illumination, what happens to the pupil?
Dilates via sympathetic innnervation
93
In a pupillary reflex, what are the names of the responses you are looking for?
Direct
| Consensual
94
What is the term used to describe pupils of different sizes? In what condition is this seen?
Anisocoria
| eg Horners syndrome
95
In the pupillary reflex, does light go to the LGB & visual cortex?
No, it goes to the midbrain to the Edinger-Westphall nucleus (part of IIIn nucleus)
96
In the pupillary reflex, where do afferent fibres go from the EWN?
Preganglionic fibres pass through orbit via IIIn & synapse in ciliary ganglion.
Postganglionic fibres inveiate constrictor pupillae = PUPIL CONSTRICTION
97
What eye related condition is associated with MS?
Optic neuritis
98
What type of conditions can impair pupillary reflex?
Intracranial bleed
99
What disease can cause damage to IIIn however parasympathetic fibres are spared?
Diabetes
100
What are the clinical signs of Horners syndrome?
Anhydrosis
Ptosis
Miosis
101
Where do postganglionic sympathetic fibres travel?
Along blood vessels
102
Name a cause of Horners syndrome & what is its pathology
Loss of sympathetic innervation to the head
Tumour
Trauma
Pancoast lung tumour
103
What components of the eye are responsible for bending light?
Cornea
| Lens
104
What is another term for the bending of light?
Refraction
105
When an object is close up, what happens to the shape of the lens? Why?
Lens becomes thicker
| Light has to bend further in order to focus on retina
106
What part of the eye is the most powerful bender of light?
Cornea
107
The focusing capacity of the eye changes from distant to close object, is called?
Accomodation
108
What are the 3 changes occur when the eye accommodates?
Lens becomes thicker & spherical
Pupil constricts
Eyes converge
109
When the ciliary muscles contract, what happens to the lens?
Thicker & spherical
| suspensory ligaments become lax
110
What innervation causes contraction of ciliary muscles?
Parasympathetic (IIIn)
111
What EOM do we use in order to converge eyes in accomdation?
MR
112
What is the clinical term for shortsightedness?
Myopia
113
In myopia, where does the light refract?
In front of the retina
114
If someone has myopia, what is there vision like?
Hazy in distance
| Clear close up
115
If someone has emmetropia, what is there vision like?
Normal
116
What are some of the symptoms of myopia?
Headaches, unable to see blackboard
| In infants = divergent squint
117
How can myopia be treated?
Reduce the bending power of lens by:
Spectacles
Contact lens
Laser eye surgery
118
What is the clinical term for farsightedness?
Hyperopia
119
If someone has hyperopia, what is there vision like?
Hazy close up
| Distant is clear
120
Why might someone suffer from hyperopia?
Eyeball too short
| Lens too flat
121
Where is the image formed in the eye in hyperopia?
Behind the retina
122
What are some of the symptoms associated with hyperopia?
Eyestrain after reading
| Convergent squint
123
What can you use to treat hyperopia?
Contact lens
Laser eye surgery
Glasses
124
Where is the light focussed when a person has astigmatismsm?
Will not be refracted into one area on retina
125
Describe the pathology of astigmatisms
Les appears oval shaped resulting in light being bent differently
126
What will someones vision with astigmatism be like?
Hazy for close & distant vision
127
Ho can you treat astigmatism?
Laser eye surgery
Special spectacles - cylindrical glasses
Contact lens - topic lenses
128
What is longsightedness in older age called?
Presbyopia
129
Why does presbyopia occur in older age?
Lens becomes less mobile therefore when ciliary muscles contract, lens less able to change shape
130
How can presbyopia be treated?
Reading glasses
131
Where are photoreceptors found?
Retina
132
Define phototransduction
Defined as a conversion of light energy to electrochemical response by photoreceptors
133
Which vitamin is associated with phototransduction? What is its role?
```
Vitamin A (retinol)
Visual pigment regeneration
```
134
What are the 2 types of photoreceptor found in the retina?
Rods & cones
135
What is the main visual pigment found in the eye?
Rhodopsin
136
What is the main source of vitamin A?
Diet
137
If there is vitamin A deficiency, what will be clinical signs?
Night blindness
138
In what conditions can vitamin A dificiency occur?
Malabsorption disease - coeliac disease
139
What are some clinical signs of vitamin A defiency observed in the eye?
Bitots spots in conjunctiva
Corneal ulceration
Opacification of cornea (silver spots)
140
What is the visual field defined as?
Everything you can see in ONE eye (including periphery)
141
Where is maximal visual acuity achieved?
Fovea centralis
142
What is absent at the optic nerve head?
Rods & cones
143
Which fibres cross at the optic chiasm?
Nasal fibres
144
Where do fibres from optic tract synapse?
LGB
145
Where is the LGB found?
Thalamus
146
In the visual cortex, which visual field does the left side of the brain perceive?
Right visual field
147
If the optic tract or optic radiation is damaged, what will happen to visual field?
Contralateral homonymous hemianopia
148
If there is damage to the optic chiasm, what will happen to the visual field?
Bitemporal hemianopia
