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Neurology > Vision > Flashcards

Flashcards in Vision Deck (109)
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1
Q

What muscles make up the iris of the eye?

A

Constrictor and radial muscles

2
Q

Name some functions of the ciliary body?

A

Suspends Lens

Produces Aqueous humour

3
Q

What is the function of the choroid?

A

Supplies blood to the outer layers of retina

4
Q

What are the three layers of the eyeball?

A

Fibrous Coat
Vascular Coat
Sensory Body

5
Q

What makes up the fibrous coat?

A

Cornea and Sclera

6
Q

What makes up the vascular coat (uvea)?

A

Iris, Ciliary Body, Choroid

7
Q

What makes up the sensory body?

A

Retina (10 layers - made up of rods and cones)

8
Q

Where is the aqueous humour located?

A

Anterior segment (in front of Lens)

9
Q

What is the function of the aqueous humour?

A

Helps maintain intraocular pressure.

It is constantly produced and reabsorbed.

10
Q

How is the anterior segment divided?

A

Anterior Chamber (In front of iris)

Posterior Chamber (behind iris

11
Q

Where does the aqueous humour travel to?

A

Produced from the ciliary body -> Posterior chamber -> Anterior chamber -> Angle of anterior chamber

12
Q

Where does the aqueous humour drain out?

A

The trabecular meshwork at the angle of the anterior chamber.

Then into Schlem’s canal -> Episcleral veins

13
Q

Where is the vitreous humour located?

A

Posterior Segment (Behind the lens)

14
Q

What is the function of the vitreous humour?

A

Cushions the retina. (Retinal detachment occurs when becomes more liquefied)

15
Q

What is the shape of the lens?

A

Biconvex (suspended in 360 degree by suspensory ligaments of ciliary muscle)

16
Q

What are the three openings of the bony orbit?

A

Optic foramen, Superior orbital fissure, Inferior orbital fissure

17
Q

What is the space in the orbit filled with?

A

Fat (to support the eyeball) - one of the last reserves of fat in starvation.

18
Q

What happens to the eyes in hyperthyroidism?

A

Hypertrophy of the orbit - causing a protruding appearance

19
Q

How does sty formation happen?

A

Eyelash sebaceous glands being blocked?

20
Q

What muscle helps to open the eyelid?

A

Levator Palpabra Superioris (LPS)

21
Q

What muscle helps to close the eyelid?

A

Orbicularis Oculi

22
Q

What is the function of the tarsal plate in the eyelid?

A

Helps to prevent the eyelid to scrunch up

23
Q

Where is the lacrimal gland located?

A

In the roof of the orbit

24
Q

What nerve provides function to the lacrimal gland?

A

The facial nerve (parasympathetic)

25
Q

What does the lacrimal fluid drain into?

A

The lacrimal sac via punctae on the medial side of the eyelid - into nasolacrimal duct.

26
Q

What does the nasolacrimal duct drain into?

A

The inferior nasal cavity

27
Q

What happens with blinking?

A

The orbicularis oculi pulls the lacrimal sac open - negative pressure pulls in tears.

28
Q

What are the intrinsic ocular muscles?

A

Ciliaris muscle, constrictor pupillae, dilator pupillae

29
Q

What is the function of the ciliaris muscle?

A

When it contracts, makes lens change shape - accommodation

30
Q

What cranial nerve controls the ciliaris muscle?

A

Oculomotor Nerve (CNIII)

31
Q

What is the function of the constrictor pupillae?

A

Pupillary constriction

32
Q

What cranial nerve controls the constrictor pupillae muscle?

A

Oculomotor Nerve (CNIII)

33
Q

What is the function of the dilator pupillae?

A

Pupillary dilatation

34
Q

What nerves controls the dilatator pupillae muscle?

A

Sympathetic nerves

35
Q

What are the extrinsic muscles of the eye?

A
Superior Rectus
Inferior Rectus
Medial Rectus
Lateral Rectus
Superior Oblique
Inferior Oblique
36
Q

What extrinsic muscles are innervated by the occulomotor nerve CNIII?

A
Superior Rectus
Inferior Rectus
Medial Rectus
Inferior Oblique
(LPS)
37
Q

What extrinsic muscles are innervated by the trochlear nerve CNIV?

A

Superior Oblique

38
Q

What extrinsic muscles are innervated by the abducens nerve CNVI?

A

Lateral Rectus

39
Q

Which of the ocular cranial nerves is most frequently damaged?

A

Abducens Nerve (CNVI)

40
Q

Where does the trochlear nerve CNIV arise from?

A

The back of the brainstem

41
Q

Where do the cranial nerves III, IV and VI enter the orbit?

A

Superior orbital fissure

42
Q

Where does the general sensory innervation to the eyeball arise from?

A

CNV1 (from trigeminal, and CNV2)

43
Q

What are the branches of the opthalmic nerve? (CNV1)

A

Nasociliary, Frontal, Lacrimal

44
Q

Where does the maxillary nerve (CNV2) enter the orbit?

A

Inferior orbital fissure

45
Q

What blood vessel supplies blood to the eye/orbit?

A

Opthalmic artery (branch of internal carotid artery)

46
Q

What artery supplies the inner layers of retina?

A

Central Retinal Artery

47
Q

Where is the physiological blindspot?

A

The optic disc

48
Q

What does the central retinal vein look like compared to the artery

A

The vein is wider and darker

49
Q

Which venous sinus does the opthalmic veins drain in to?

A

Cavernous sinus

50
Q

Where does the cavernous sinus drain into?

A

The internal jugular veins (exit through the jugular foramen)

51
Q

What does the cavernous sins lie to either side of?

A

The body of the sphenoid bone.

52
Q

In embryology, what induces ectodermal cells to enlarge and form the nueral plate?

A

The notochord

53
Q

What does the neural plate fold up to become?

A

The neural tube

54
Q

What part of the neural tube gives rise to optic vesicles?

A

Diencephalon

55
Q

How is the lens placode formed?

A

Optic vesicles induce surface epithelium to thicken

56
Q

What does the optic vesicle form?

A

Optic cup

57
Q

What forms the choroid, sclera and extraocular muscle in the developing embryo?

A

Surrounding mesenchyme

58
Q

What form the lens?

A

Lens vesicle

59
Q

What forms the cornea, conjunctiva, eyelids?

A

Surface epithelium

60
Q

Between which layers of retina can a potential space form?

A

9-10

61
Q

What is refraction?

A

The bending of light from one optical medium to another

62
Q

What make up the refractive media in the eyeball?

A

Cornea, Aqueous Humour, Lens

63
Q

What happens to the lens as an object becomes closer?

A

The lens becomes thicker

To form a clear image on the retina

64
Q

Which of the refractive media is the most powerful?

A

The cornea

65
Q

What is the term used to describe the changes in both eyes as it changes focus from a distant object to a close object?

A

Accommodation

66
Q

What three things comprise accommodation?

A

Lens changes shape (ciliary body contraction)

Pupil constricts

Eyes converge

67
Q

What controls all three aspects of accomodation?

A

Parasympathetic innervation from CNIII (Oculomotor Nerve)

68
Q

What term describes a refractory error causing short-sightedness?

A

Myopia

69
Q

What term describes a refractory error causing long-sightedness?

A

Hyperopia

70
Q

What term describes a refractory error causing non-spherical curvature of the cornea?

A

Astigmatism

71
Q

What term describes a refractory error causing long-sightedness in old age?

A

Presbyopia

72
Q

What is phototransduction?

A

Light waves stimulating photoreceptor cells in the retina

73
Q

What is the visual pigment in rods and cones?

A

Rhodopsin (Opsin + Retinal)

74
Q

What vitamin forms the chromophore in opsin?

A

Vitamin A

75
Q

What happens when rhodopsin splits?

A

Bleaching

76
Q

What role does vitamin A from the liver play in the visual pigment?

A

Visual pigment regeneration

77
Q

What can happen to the eyes in response to raised ICP?

A

Increased pressure around optic nerves

78
Q

What is the descriptive term for everything seen with one eye?

A

Visual field

79
Q

Where is the area of peak central vision?

A

Fovea centralis

80
Q

What happens to objects in the visual field?

A

Formed upside down and inverted on the retina

81
Q

Where to fibres from the optic nerve pass to?

A

The optic chiasm

82
Q

What happens at the optic chiasm?

A

Medial nasal fibres cross to the opposite side

83
Q

What fibres does each optic tract contain?

A

Fibres from the (lateral) temporal half of the ipsilateral eye and the crossed-over nasal fibres from the contralateral eye.

84
Q

Where do the optic tract fibres synapse?

A

The Lateral Geniculate Body (LGB) of the thalamus

85
Q

Where is the Primary Visual Cortex located?

A

Occipital Lobe

86
Q

What visual disruption occurs when the right optic nerve is damaged?

A

Blindness in R Eye

87
Q

What visual disruption occurs when the optic chiasm is damaged?

A

Bitemporal Hemianopia

88
Q

What visual disruption occurs when the right optic tract is damaged?

A

Contralateral Homonymous Haemianopia

89
Q

What visual disruption occurs when the right optic radiation is damaged?

A

Contralateral Homonymous Haemianopia

90
Q

What is the function of intrinsic eye muscles?

A

Control pupil diameter & helps alter lens curvature to enable us to see near objects

91
Q

What is the function of extrinsic eye muscles?

A

Move the eye

92
Q

What is the action of the Lateral Rectus?

A

Abduction

93
Q

What is the action of the Medial Rectus?

A

Adduction

94
Q

What is the action of the Superior Rectus?

A

Elevation
Adduction
Intorsion

95
Q

What is the action of the Inferior Rectus?

A

Depression
Adduction
Extorsion

96
Q

What is the action of the Superior Oblique?

A

Intorsion
Depression
Abduction

97
Q

What is the action of the Inferior Oblique?

A

Extorsion
Elevation
Abduction

98
Q

What does the terminology RADSIN refer to?

A

Recti ADductors,

Superiors INtortors

99
Q

What terminology means misalignment of eyes?

A

Strabismus (Squint)

100
Q

What are the functional consequences of squint?

A
  • Amblyopia (lazy eye)

- Diplopia (double vision)

101
Q

What does increased illumination do to pupils?

A

Constriction (through parasympathetic innervation)

102
Q

What does decreased illumination do to pupils?

A

Dilation (through sympathetic innervation)

103
Q

Where does the afferent limb of the light reflex travel to?

A

The midbrain (where the IIIn nucleus is located)

104
Q

Does conjunctiva cover the cornea?

A

No

105
Q

What is the epithelium of the cornea?

A

Stratified squamous non-keratinised

106
Q

What is the bowman’s membrane?

A

Basement membrane of corneal epithelium

107
Q

What is the regularly arranged layer of collagen known as beneath bowman’s membrane?

A

Stroma

108
Q

Why is the avascularity of the cornea beneficial for graft surgery?

A

Lesser chance of foreign antigens from a corneal graft being recognised by the recipient -> lesser chance of a graft rejection.

109
Q

What are consequences of raised IOP?

A

Pressure on nerve fibres on surface of retina -> die out -> visual field defects

Altered field of vision