Eye Anatomy Flashcards Preview

Neurology > Eye Anatomy > Flashcards

Flashcards in Eye Anatomy Deck (148)
Loading 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
Q

Which area of the orbit is the weakest?

A

Medial & inferior walls of the orbit

26
Q

What cushions the eyeball in the orbit?

A

Periorbital fat

27
Q

What is another name for the mucosa membrane on the inside of the eyelid?

A

Conjuntiva

28
Q

What type of gland is associated with eyelashes?

A

Sebaceous gland

29
Q

What muscle is responsible for elevating the eyelid?

A

Levator palpebrae superioris

30
Q

What is the name of the hard plate found in the eye lid?

A

Tarsal plate

31
Q

What is the name of the glands found in association with the tarsal plate in the eyelid which produce oily secretions?

A

Meibomian glands

32
Q

What are the different areas of the conjuntiva called?

A

Palpebral conjunctiva
Ocular conjunctiva
Superior/ Inferior fornix

33
Q

What does the ocular conjunctiva cover?

A

Sclera

34
Q

Which nerve stimulates the lacrimal gland?

A

Facial nerve (parasympathetic)

35
Q

Where do tears drain from the eyeball?

A

Via punctate in the medial side of eye into lacrimal sac

36
Q

Where do tears drain from the lacrimal sac?

A

Nasolacrimal duct

37
Q

Where does the nasolacrimal duct drain?

A

Inferior meatus

38
Q

What do intrinsic muscles of the eye control?

A

Pupil diameter & regulate lens curvature

39
Q

What do extra ocular muscles control?

A

The movement of the eyeball

40
Q

What muscle constricts the iris? What innervation?

A
Constrictor pupillae (circular)
Parasympathetic - IIIn
41
Q

What muscle dilates the iris? What innervation?

A
Dilator pupillae (radial)
Sympathetic nerves
42
Q

What innervates the ciliary body muscles?

A

Parasympathetic (IIIn)

43
Q

When the ciliary bodies are activated what happens to the structure of the lens? What is this called?

A

Thicker & rounded
Focus close up

Accomodatio

44
Q

How many straight muscle (recti) are found in the eye orbit?

A

4 - SR, LR, MR, IR

45
Q

How many oblique muscles are there?

A

2 - SO, IO

46
Q

Where do the recti muscles arise/insert?

A

Apex of orbit from annular fibrous ring & insert anteriorly to sclera

47
Q

Where does the SO arise/insert?

A

Roof of orbit & insert posteriorly to sclera

48
Q

Where does the IO arise/insert?

A

Floor of orbit anteriorly & insert posteriorly

49
Q

What nerve supplies the LR?

A

Abducent nerve (VI)

50
Q

What nerve supplies the SO?

A

Trochlear nerve (IV)

51
Q

What nerve supplies the IO

A

Oculomotor nerve (III)

52
Q

Where do parasympathetic fibres carried by IIIn synapse?

A

Ciliary ganglion

53
Q

Which nerve carries sensory information to the orbit?

A

Trigeminal nerve (V1 & 2)

54
Q

Where dos the maxillary division of trigeminal exit onto the face?

A

Infraorbital foramen

55
Q

What is the ophthalmic artery a branch of?

A

ICA

56
Q

What branch of the ophthalmic artery travels within the optic nerve?

A

Central retinal artery

57
Q

What is another name for the physiological blind spot?

A

Optic disc

58
Q

What is the name of the area of retina which has a high density of cones?

A

Fovea centralis

59
Q

What are the 4 divisions the retina is divided into?

A

Superonasal
Superotemporal
Inferonasal
Inferotemporal

60
Q

Where do the superior & inferior ophthalmic veins drain into?

A

Cavernous sinus

61
Q

Which germ layer do eyes originate?

A

Ectoderm (from neural tube)

62
Q

Where do optic vesicles grow out from?

A

Diencephalic part of neural tube

63
Q

What forms after the optic vesicle in embryonic development of eye?

A

Optic cup

64
Q

What embryological layer forms the EOM?

A

Mesenchyme (mesoderm)

65
Q

What epithelial layer is found at the cornea?

A

Stratified squamous non-keratinised epithelium

66
Q

What is another name for the basement membrane at the corneal epithelium?

A

Bowman’s membrane

67
Q

What is the thickest layer in the cornea called?

A

Stroma

68
Q

What is the stroma of the cornea composed of?

A

Regularly arranged collagen

69
Q

How many histological layers are present at the cornea?

A

5

70
Q

What factors contribute to the cornea being transparent?

A

Regularly arranged collagen fibres in stroma
No blood vessles
Endothelial layer has pump which keeps AH out

71
Q

Why does the avascularity of the cornea contribute to effective corneal transplants?

A

Less risk of rejection

72
Q

How many layers compose the retina?

A

10 layers

73
Q

What is the 1st layer of the retina composed of?

A

Pigmented epithelium

74
Q

What is the 2nd retinal layer composed of?

A

Rods & cones

75
Q

What is lens opacification called?

A

Cataract

76
Q

What are the functions of the tear film?

A

Keeps cornea moist
Washes away particles of foreign body
Has antibodies
Smooths outer layer of cornea for refraction

77
Q

Clinically how can you visualise the tear film?

A

Staining with fluorescein

78
Q

How many layers compose the tear film?

A

3

1: mucinous layer
2: aqueous layer
3: oily layer

79
Q

Which muscles elevate/depress the eye when it is adducted?

A

Oblique muscles

80
Q

Which muscles elevate/depress the eye when it is abducted?

A

SR/IR

81
Q

What is the mnemonic used to remember EOM movements?

A

RADSIN
Recti adductors
Superior intortors

82
Q

What are the actions of the SR?

A

Elevation
Adduction
Intorsion

83
Q

What are the actions of the IR?

A

Depression
Adduction
Extorsion

84
Q

What are the actions of the SO?

A

Depression
Abduction
Intorsion

85
Q

What are the actions of the IO?

A

Elevation
Extorsion
Abduction

86
Q

What is the clinical term for squint?

A

Strabismus

87
Q

What is the name of a convergent squint?

A

Esotropia

88
Q

What is the name of a divergent squint?

A

Exotropia

89
Q

What is amblyopia?

A

A lazy eye caused as a result of squint left uncorrected leading to suppression of image

90
Q

What are the functional consequences of a squint?

A

Amblyopia

Diplopia

91
Q

When there is an increase in illumination, what happens to the pupil?

A

Constricts via IIIn parasympathetic fibres

92
Q

When there is an decrease in illumination, what happens to the pupil?

A

Dilates via sympathetic innnervation

93
Q

In a pupillary reflex, what are the names of the responses you are looking for?

A

Direct

Consensual

94
Q

What is the term used to describe pupils of different sizes? In what condition is this seen?

A

Anisocoria

eg Horners syndrome

95
Q

In the pupillary reflex, does light go to the LGB & visual cortex?

A

No, it goes to the midbrain to the Edinger-Westphall nucleus (part of IIIn nucleus)

96
Q

In the pupillary reflex, where do afferent fibres go from the EWN?

A

Preganglionic fibres pass through orbit via IIIn & synapse in ciliary ganglion.
Postganglionic fibres inveiate constrictor pupillae = PUPIL CONSTRICTION

97
Q

What eye related condition is associated with MS?

A

Optic neuritis

98
Q

What type of conditions can impair pupillary reflex?

A

Intracranial bleed

99
Q

What disease can cause damage to IIIn however parasympathetic fibres are spared?

A

Diabetes

100
Q

What are the clinical signs of Horners syndrome?

A

Anhydrosis
Ptosis
Miosis

101
Q

Where do postganglionic sympathetic fibres travel?

A

Along blood vessels

102
Q

Name a cause of Horners syndrome & what is its pathology

A

Loss of sympathetic innervation to the head

Tumour
Trauma
Pancoast lung tumour

103
Q

What components of the eye are responsible for bending light?

A

Cornea

Lens

104
Q

What is another term for the bending of light?

A

Refraction

105
Q

When an object is close up, what happens to the shape of the lens? Why?

A

Lens becomes thicker

Light has to bend further in order to focus on retina

106
Q

What part of the eye is the most powerful bender of light?

A

Cornea

107
Q

The focusing capacity of the eye changes from distant to close object, is called?

A

Accomodation

108
Q

What are the 3 changes occur when the eye accommodates?

A

Lens becomes thicker & spherical
Pupil constricts
Eyes converge

109
Q

When the ciliary muscles contract, what happens to the lens?

A

Thicker & spherical

suspensory ligaments become lax

110
Q

What innervation causes contraction of ciliary muscles?

A

Parasympathetic (IIIn)

111
Q

What EOM do we use in order to converge eyes in accomdation?

A

MR

112
Q

What is the clinical term for shortsightedness?

A

Myopia

113
Q

In myopia, where does the light refract?

A

In front of the retina

114
Q

If someone has myopia, what is there vision like?

A

Hazy in distance

Clear close up

115
Q

If someone has emmetropia, what is there vision like?

A

Normal

116
Q

What are some of the symptoms of myopia?

A

Headaches, unable to see blackboard

In infants = divergent squint

117
Q

How can myopia be treated?

A

Reduce the bending power of lens by:
Spectacles
Contact lens
Laser eye surgery

118
Q

What is the clinical term for farsightedness?

A

Hyperopia

119
Q

If someone has hyperopia, what is there vision like?

A

Hazy close up

Distant is clear

120
Q

Why might someone suffer from hyperopia?

A

Eyeball too short

Lens too flat

121
Q

Where is the image formed in the eye in hyperopia?

A

Behind the retina

122
Q

What are some of the symptoms associated with hyperopia?

A

Eyestrain after reading

Convergent squint

123
Q

What can you use to treat hyperopia?

A

Contact lens
Laser eye surgery
Glasses

124
Q

Where is the light focussed when a person has astigmatismsm?

A

Will not be refracted into one area on retina

125
Q

Describe the pathology of astigmatisms

A

Les appears oval shaped resulting in light being bent differently

126
Q

What will someones vision with astigmatism be like?

A

Hazy for close & distant vision

127
Q

Ho can you treat astigmatism?

A

Laser eye surgery
Special spectacles - cylindrical glasses
Contact lens - topic lenses

128
Q

What is longsightedness in older age called?

A

Presbyopia

129
Q

Why does presbyopia occur in older age?

A

Lens becomes less mobile therefore when ciliary muscles contract, lens less able to change shape

130
Q

How can presbyopia be treated?

A

Reading glasses

131
Q

Where are photoreceptors found?

A

Retina

132
Q

Define phototransduction

A

Defined as a conversion of light energy to electrochemical response by photoreceptors

133
Q

Which vitamin is associated with phototransduction? What is its role?

A
Vitamin A (retinol)
Visual pigment regeneration
134
Q

What are the 2 types of photoreceptor found in the retina?

A

Rods & cones

135
Q

What is the main visual pigment found in the eye?

A

Rhodopsin

136
Q

What is the main source of vitamin A?

A

Diet

137
Q

If there is vitamin A deficiency, what will be clinical signs?

A

Night blindness

138
Q

In what conditions can vitamin A dificiency occur?

A

Malabsorption disease - coeliac disease

139
Q

What are some clinical signs of vitamin A defiency observed in the eye?

A

Bitots spots in conjunctiva
Corneal ulceration
Opacification of cornea (silver spots)

140
Q

What is the visual field defined as?

A

Everything you can see in ONE eye (including periphery)

141
Q

Where is maximal visual acuity achieved?

A

Fovea centralis

142
Q

What is absent at the optic nerve head?

A

Rods & cones

143
Q

Which fibres cross at the optic chiasm?

A

Nasal fibres

144
Q

Where do fibres from optic tract synapse?

A

LGB

145
Q

Where is the LGB found?

A

Thalamus

146
Q

In the visual cortex, which visual field does the left side of the brain perceive?

A

Right visual field

147
Q

If the optic tract or optic radiation is damaged, what will happen to visual field?

A

Contralateral homonymous hemianopia

148
Q

If there is damage to the optic chiasm, what will happen to the visual field?

A

Bitemporal hemianopia