OP Anatomy Flashcards
(93 cards)
1
Q
Which 2 parts of the orbit are most vulnerable to trauma?
A
Medial wall & orbital floor
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2
Q
What can be damaged in an orbital blowout fracture?
A
Infraorbital NVB
3
Q
What is the orbital septum?
A
A sheet of fscia
4
Q
What is the outermost muscle of the eyelid?
A
Orbicularis oculi
5
Q
What is the limbus also known as?
A
Corneoscleral junction
6
Q
Which nerve gives parasympathetic supply to the lacrimal gland?
A
CN VII (facial nerve)
7
Q
What do tears drain through?
A
Lacrimal puncta into the inferior meatus
8
Q
What are the 2 parts of the fibrous outer layer of the eye?
A
Sclera
Cornea
9
Q
What is the purpose of the sclera?
A
Muscle attachment
10
Q
What is the purpose of the cornea?
A
Refraction
11
Q
What are the 3 parts of the uvea?
A
Iris
Cilliary body
Choroid
12
Q
What is the function of the iris?
A
Adjust pupil diameter
13
Q
What are the functions of the cilliary bodies?
A
Control iris, shape of lens and secretion of aqueous humour
14
Q
What is the function of the choroid?
A
Nutrition and gas exchange
15
Q
Where is the anterior chamber?
A
Between cornea & iris
16
Q
What is in the anterior chamber?
A
Aqueous humour
17
Q
Where is the posterior chamber?
A
Between iris and suspensory ligaments
18
Q
What is found in the posterior chamber?
A
Aqueous humour
19
Q
What is found in the posterior segment of the eye?
A
Vitreous humour
20
Q
Where is aqueous secreted from?
A
Ciliary processes
21
Q
What is the circulation of aqueous?
A
Ciliary body
Then goes into posterior chamber to nourish lens
Then goes into anterior chamber to nourish cornea
It is then reabsorbed at the canal of schlemm
22
Q
What are the 3 parts of the fundus?
A
Optic disc
Macula
Fovea
23
Q
Where is the point of CN II formation?
A
Optic disc
24
Q
What is the ‘blind spot’ caused by?
A
Optic disc
25
Where is the area of most acute vision?
Fovea
26
Which is thicker on fundoscopy, artery or vein?
Vein
27
What are the 3 layers of the retina? (posterior to anterior)
Photorecptors
Ganglion cells
Axons of ganglion cells
28
Where is light from objects in the right visual field processed?
Left visual cortex
29
Where is light from objects in the lower visual field processed?
Upper part of the primary visual cortex
30
What is the only vein to drain the retina?
Central vein of the retina
31
What is the opthalmic artery a branch of?
Internal carotid artery
32
Where do all of the rectus muscles originate?
Common tendonous ring
33
What is the function of the levator palpebrae superioris?
Lifts upper eyelid
34
Where do the oblique & rectus muscles insert?
Sclera
35
Which nerve supplies the lateral rectus?
CN VI
36
Which nerve supplies the superior oblique?
CN IV
37
Which nerve supplies all the other EO muscles?
CN III
38
What are the only 2 eye muscles to not have a secondary movement?
Medial ~& lateral rectus
39
What effect does the superior rectus have on the eye?
Elevation
40
What effect does the inferior rectus have on the eye?
Depression
41
What effect does the suprior oblique have on the eye?
Depression
42
What effect does the inferior oblique have on the eye?
Elevation
43
What effect does the lateral rectus have on the eye?
Abduction
44
When the eye is abducted with 2 muscles allow elevation & depression?
Superior & inferior rectus
45
What effect does the medial rectus have on the eye?
Adduction
46
Which muscles elevate & depress the eye when in adduction?
Superior & inferior oblique
47
Which muscles are involved in pure elevation?
Superior rectus
| Inferior oblique
48
Which muscles are involved in pure depression/
Inferior rectus
| Superior oblique
49
In what direction does the zygoma tend to rotate if fractured?
Medially
50
Why does zygomatic fracture cause diplopia?
Suspensory ligament of the ele attaches to the zygoma laterally and injury may result in this being lowered towards the orbital floor
51
What is the suspensory ligament of the eye?
A thick fascial sling that holds the eye just above the floor of the orbit
52
How can orbital trauma cause a general sensory deficit of the facial skin?
Damage to infrrarbital NVB
53
Which nerves supplies the general sensory supply to the upper eyelid, cornea, conjunctiva, skin of the root/bridge/tip of the nose?
CN V1
54
Which nerves supplies the skin of the lower eyelid, the skin over the maxilla, the skin of the ala of the nose, the skin/mucosa of the upper lip?
CN V2
55
Which nerve supplies the skin over the mandible and TMJ?
CN V3
56
Which nerves supply the angle of the mandible?
C2,3 spinal nerves
57
What is involved in the sensory limb of the blink (corneal) reflex?
Action potentials are conducted centrally via CN V1 to the trigeminal ganglion then in CN V to the pons
58
What is involved in the efferent (motor) limb of the blink (corneal) reflex?
Action potentials are conducted peripherally in CN VII to the eyelid part of the orbicularis oculi
59
What is released from the sympathetic presynaptic axon?
Acetylcholine
60
What is released for the sympathetic postsynaptic axon?
Noradrenaline
61
Where do the presynaptic sympathetic axons synapse for supply to the head & neck region?
Cervical sympathetic ganglion
62
What carries sympathetic axons into the orbit?
Ophthalmic artery
63
What is release from the presynaptic axon in the parasympathetic system?
Acetylchholine
64
What is released from the postsynaptic axon in the parasympathetic system?
Acetylcholine
65
Where do all parasympathetic axons leave the CNS?
CN III, VII, IX & X
66
What does CN VII provide parasympathetic innervation to?
Lacrimal gland
Submandibular & sublingual salivary glands
Parotid salivary gland
67
Where does the vagus nerve provide parasympathetic innervation for?
Organs of the neck & chest & abdomen as far as the midgut
68
Where do the sacral spinal nerve carry parasympathetic axons to?
Hindgut
Pelvis
Perineum
69
What does the occulomotor nerve supply somatic motor to?
SR
MR
IR
IO
70
What does the occulomotor nerve supply parasymathetic axons to?
Ciliary ganglion
71
Which nerves control the diameter of the iris and the refractive shape of the lens?
Ciliary nerves
72
What is the oculocardiac reflex?
Reflex bradycardia in response to tension on the extraocular muscles or pressure in the eye (CNS connections between CN V1 & CN X)`
73
Sympathetic functions on the eye
Open eyes wider
Get more light into eyes
Focus on far objects
Emotional lacrimation
74
Parasympathetic functions on the eye
Allow orbicularis oculi to work
Get less light into eyes
Focus on near objects
Reflex lacrimation
75
What type of muscle is the levator palpebrae?
Skeletal & smooth muscle
76
How do axons get from the superior cervical symapthetic ganglion to the obrital structures?
Internal carotid nerve
Internal carotid plexus
Opthalmic artery
Branches to orbital structures
77
What kind of drugs dilate the pupil?
Mydriatic drugs
78
What drugs can cause a pinpoint pupil?
Opiates
79
What is a miotic pupil a compnent of?
Horner's syndrome
80
What is a fixed dilated pupil a pathological sign of?
CN III pathology
81
Whats is the direct light reflex?
Constriction of the pupil that the light is shone in
82
What is the consensual light reflex?
Constriction of the pupil in the non-stimulated eye
83
What the first neurone that pass via the ipsilateral optic nerve to deccusate in the optic chiasm then synapse in the pretectal nucleus in the midbrain?
Retinal ganglion cells
84
Where do the second neurones synapse in the light reflex?
Edinger Westphal nucelus
85
Where do the 3rd neurones in the light reflex synapse?
Ciliary ganglion
86
Where do the 4th neurones in the light reflex travel?
Short ciliary nerves to the sphincter pupillae muscles
87
Does the sphincter muscle contract or relax in far vision?
Relax and flatten
88
Does the ciliary muscle contract or relax when reading a book?
Contract (become spherical)
89
What are the 3 components of the accomodation reflex?
Bilateral pupillary constriction
Bi;atera; convergance
Bilateral relaxation of the lens
90
Which nerve controls the accomodation reflex?
CN III
91
What enzyme within tears helps to clean the cornea?
Lysozyme
92
What is the afferent limb of reflex tears?
CN V1
93
What is the efferent limb of reflex tears?
CN VII
