Embryology/Anatomy of Eye Flashcards Preview

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Flashcards in Embryology/Anatomy of Eye Deck (62)
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1
Q

from what structure in the embryo does the brain and spinal cord form from?

A

the neural tube

2
Q

from what part of the neural tube does the optic vesicles form from?

A

diencephalic part

3
Q

what do the optic vesicles in the embryo form?

A

the eyes

4
Q

in which direction do the optic vesicles grow?

A

grow laterally towards the ectoderm

5
Q

as the optic vesicle grows towards the ectoderm what happens?

A

the ectoderm layer becomes thicker and forms the lens placode

6
Q

what is formed when the lens placode pushes inwards?

A

optic cup

7
Q

how many layers does the optic cup have?

A

2

8
Q

through which fissure do the blood vessels which are located on the inferior wall of the optic cup pass through?

A

choroid fissure

9
Q

how many layers of the retina are there?

A

10

10
Q

from which layer do most of the layers of the retina form from?

A

the inner layer

11
Q

between which layers of the retina is there a potential space?

A

between the 9th and 10th

12
Q

what happens to the choroid fissure in adult hood ?

A

it obliterates

13
Q

what can occur if the choroid fissure is present in adult hood?

A

causes the development of a coloboma

14
Q

where are the three places where a coloboma can occur?

A

iris
retina
disc

15
Q

what are the choroid, stoma of the cornea, sclera and extra ocular muscles formed from?

A

mesenchyme

16
Q

what is the conjunctiva formed from?

A

surface ectoderm

17
Q

does the orbit have thick or thin walls?

A

thin

18
Q

is the orbit rims weak or strong?

A

strong

19
Q

what is the size of the eye ball?

A

2.1cm

20
Q

what is the length of the eye canal?

A

8cm

21
Q

why are the medial and inferior walls of the orbit weak?

A

because they are very close to sinuses so the thin walls can explode and cause hernia of the eye socket contents

22
Q

what is the characteristic sign of a orbital floor fracture on a CT scan?

A

tear drop sign

23
Q

what eye action can someone with an orbital floor fracture not be able to do?

A

elevation

24
Q

what is the main function of orbital fat?

A

support of the eye ball

25
Q

when there is hypertrophy of orbital fat, what can occur?

A

patient would have a staring appearance

26
Q

what attaches to the sclera?

A

muscles for moving the eye ball

27
Q

what is the epithelium on the cornea ?

A

stratified squamous non-keratinised

28
Q

what is the basement layer of the corneal epithelium called?

A

bowmans membrane

29
Q

what is contained in the stroma of the cornea?

A

regularly arranged collagen

30
Q

what separates the cornea and the aqueous humour ?

A

single layer of squamous epithelium

31
Q

are there any blood vessels in the cornea ?

A

no

32
Q

what three things maintains cornea transparency

A
  1. regular arrangement of collagen
  2. no blood vessels
  3. pump at single epithelium layer which keeps aqueous fluid out
33
Q

what is a corneal transplant called?

A

keratoplasty

34
Q

state an inflammatory pathology of the cornea

A

corneal ulcer

35
Q

state an non- inflammatory pathology of the cornea

A

dystrophies

36
Q

is it hard or easy to find a corneal donor?

A

easy

37
Q

is there is low or high chance of rejection for corneal transplants ?

A

low risk of rejection

38
Q

why is there is low risk of rejections of corneal transplants?

A

the cornea is avascular so there is a less chance of foreign antigens being recognised by the recipient

39
Q

which layer of the retina absorbs excess light in the eye?

A

the 1st layer (next to the choroid)

= pigment epithelial layer

40
Q

which layer contains cones and rods?

A

2nd layer

41
Q

which layer of the retina contains the nerve fibres?

A

9th layer

42
Q

what are the four quadrants of the retina?

A

superonasal
inferonasal

superotemporal
inferotemporal

43
Q

at the optic nerve head, what are the differences between the ophthalmic arteries and veins?

A

arteries

  • thinner
  • lighter

veins

  • larger
  • darker
44
Q

what is the area with lots of cones medial of the retina called?

A

fovea centralis

45
Q

what autonomic response dilates the pupil?

A

sympathetic

46
Q

are there blood vessels in the lens?

A

no

47
Q

what is lens opacification called?

A

cataract

48
Q

what are the two chambers of the eye called?

A

anterior chamber

posterior chamber

49
Q

what divides the two chambers of the eye ?

A

the lens

50
Q

what is the function of the aqueous humour?

A

maintains intraocular pressure

51
Q

what is the function of the vitreous humour?

A

cushions the retina

52
Q

what is the viscosity of the AH and VH?

A
AH  = watery fluid 
VH = gel
53
Q

where is aqueous humour produced?

A

ciliary body

54
Q

where is aqueous humour filtered out of the anterior chamber ?

A

trabecular meshwork

55
Q

what canal does the aqueous humour flow out of the anterior chamber ?

A

schlemms canal

56
Q

what is the condition caused by increased intraocular pressure ?

A

glaucoma

57
Q

is the cornea covered by conjunctiva ?

A

no

58
Q

what is the conjunctiva over the sclera called?

A

bulbar

59
Q

what is the conjunctiva over the inner surface of the eyelid called?

A

palpebral

60
Q

where is the lacrimal gland located?

A

lateral to the orbit

61
Q

what is the journey which tears follow?

A
  1. produced by the lacrimal gland
  2. lacrimal gland ducts open up to the conjunctiva sac
  3. tears drain into the lacrimal sac
  4. tears drain through the nasolacrimal duct into the inferior meatus of the nasal cavity
62
Q

what autonomic response causes tears to be produced?

A

parasympathetic