The orbit and the Eye Flashcards

1
Q

Describe the papyrcea

A

medial wall containing sinuses

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2
Q

Describe the function of the orbital rim

A

thick wall, good at protecting the eye unless there is exophthalmos or piercing object

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3
Q

What is the risk with a blowout fracture?

A

Damage the infraorbital neurovascular bundle; resulting in a sensory deficit

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4
Q

What causes a blowout fracture?

A

Pressure increase inside the orbit rises dramatically, inferior or medial bones will fracture to release pressure

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5
Q

What are the four components of the eyelids?

A

Outer skin
Inner conjunctiva
Eyelashes
Glands

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6
Q

What is the function of the tarsal plate ?

A

Maintains shape and contains meibomian glands

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7
Q

What is the role of meibomian glands?

A

secrete lipids

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8
Q

What is the innervation pattern of obicularis oculi?

A

facial nerve

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9
Q

What is the result of obicularis oculi contraction?

A

closure of the eye

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10
Q

What does occulomotor nerve palsy result in?

A

Not be able to open your eye- ptosis

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11
Q

What is the limbus?

A

Corneoscleral junction

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12
Q

Which layers of the eye are continuous?

A

Cornea and sclera

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13
Q

What nerve is responsible for production of tears?

A

Parasympathetic CN 7 (facial)

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14
Q

What is the function of tears?

A

Wash over eye - lubrication

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15
Q

Describe the sclera?

A

White fibrous layer

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16
Q

Describe the function of the cornea?

A

refraction

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17
Q

What is the uvea?

A

Vascular middle layer

  • iris
  • ciliary body
  • choroid
18
Q

What is the function of the iris?

A

Control pupil diameter

19
Q

What is the function of the ciliary body?

A

Controls iris, shape of lens, secreted aqueous humour

20
Q

What is the function of the choroid?

A

Nutrition and gas exchange

21
Q

Why does the choroid appear black?

A

Vasculature and melanin

22
Q

What is the function of the retina?

A

Photosensitive inner layer containing rods and cones

23
Q

What is the anterior chamber of the eye ?

A

Infront of lens; between cornea and iris

Contains aqueous humour

24
Q

What is the posterior chamber of the eye?

A

Behind lens

Contains vitreous humour

25
Q

Where is a common location for floaters?

A

Posterior segment of the eye

26
Q

List the steps in circulation of aqueous humour?

A
  1. Ciliary body
    - smooth muscle and blood vessels, ciliary processes secrete aqueous humour
  2. Aqueous circulates
    - within posterior chamber, nourishes lens
  3. Aqruous passes though pupil
    - into anterior chamber and nourished cornea
  4. Aqueous reabsorberd
    - into scleral venous sinus (canal of schlemm)
    - at iridocorneal angle
27
Q

List the layers of the retina from posterior to anterior?

A
  1. Photoreceptors
  2. Ganglion cells
  3. Axons of ganglion cells
28
Q

What is the optic disc?

A

Point of CN II formation

only point of exit/entry for blood vessels and axons of CN II

blind spot

29
Q

What is the macula?

A

Area with greatest density of cones

30
Q

What is the fovea?

A

Centre of the macula

Depression, 1.5mm diameter

Area of most acute vision

31
Q

What does complete interruption of flow in a retinal artery branch/vein cause?

A

Loss of area of visual field corresponding to the area of ischaemia

32
Q

What causes monocular blindness?

A

Complete interruption of flow from the central artery or vein

33
Q

Which extrinsic muscles of the eye are innervated by the oculomotor nerve?

A

Medial Rectus
Superior Rectus
Inferior Rectus
Inferior Oblique

34
Q

Which extrinsic muscle of the eye is innervated by the abducens nerve?

A

Lateral rectus

35
Q

Which extrinsic muscle of the eye is innervated by the trochlear nerve?

A

Superior oblique

36
Q

Describe the function of the lateral rectus?

A

Abduction of the eye

37
Q

Describe the function of the medial rectus?

A

Medial movement of the eye

38
Q

Describe the function of the superior rectus?

A

Up and in

39
Q

Describe the function of the inferior rectus?

A

Down and In

40
Q

Describe the function of the superior oblique?

A

Down and out

41
Q

Describe the function of the inferior oblique?

A

Up and out