Eye Anatomy Flashcards Preview

Neurology > Eye Anatomy > Flashcards

Flashcards in Eye Anatomy Deck (148)
1

What are the parts of the fibrous coat of the eyeball?

Sclera & cornea

2

What are the parts of the vascular coat of the eyeball?

Choroid
Ciliary body
Iris

3

What are the parts of the sensory coat of the eyeball?

Retina

4

What is the function of the sclera?

Gives attachments to the extrocular muscles

5

How much of the fibrous coat does the sclera make up?

5/6th
(opaque)

6

What is the function of the cornea?

Allows light to enter the eye

7

How much of the fibrous coat does the cornea make up?

1/6th
Transparent

8

What is the function of the choroid?

Supplies blood to outer layer of retina

9

What is the function of ciliary bodies?

Produces Aqueous humor
Suspends the lens

10

What is the function of the iris?

Controls the diameter of the pupil & therefore the amount of light entering the eye

11

What is the function of the retina?

Has rods & cones which enable us to see

12

Where is vitreous humor found?

Posterior segment

13

Where is AH found?

Anterior segment

14

What is the structure of the lens described as?

Biconvex crystalline structure that is suspended from the ciliary body by suspensory ligaments

15

What is the function of the AH?

It maintains intraocular pressure

16

What is the function of VH?

Cushions the retina

17

What is the anterior segment further divided into?

Anterior & posterior chamber

18

Where is the Anterior chamber found?

In front of the iris

19

Where is the anterior segment found?

In front of the lens

20

Where is the posterior chamber found?

Behind the iris

21

Where is the posterior segment found?

Behind the lens

22

At the angle of the anterior chamber where does AH drain?

Via trabecular meshwork into the Schlemms canal

23

What are the names of the 3 entry/exit points in the bony orbit?

Optic foramen
Superior orbital fissure
Inferior orbital fissure

24

Which paranasal sinuses is the orbit closely related to?

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