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Flashcards in OP Anatomy Deck (93):
1

Which 2 parts of the orbit are most vulnerable to trauma?

Medial wall & orbital floor
`

2

What can be damaged in an orbital blowout fracture?

Infraorbital NVB

3

What is the orbital septum?

A sheet of fscia

4

What is the outermost muscle of the eyelid?

Orbicularis oculi

5

What is the limbus also known as?

Corneoscleral junction

6

Which nerve gives parasympathetic supply to the lacrimal gland?

CN VII (facial nerve)

7

What do tears drain through?

Lacrimal puncta into the inferior meatus

8

What are the 2 parts of the fibrous outer layer of the eye?

Sclera
Cornea

9

What is the purpose of the sclera?

Muscle attachment

10

What is the purpose of the cornea?

Refraction

11

What are the 3 parts of the uvea?

Iris
Cilliary body
Choroid

12

What is the function of the iris?

Adjust pupil diameter

13

What are the functions of the cilliary bodies?

Control iris, shape of lens and secretion of aqueous humour

14

What is the function of the choroid?

Nutrition and gas exchange

15

Where is the anterior chamber?

Between cornea & iris

16

What is in the anterior chamber?

Aqueous humour

17

Where is the posterior chamber?

Between iris and suspensory ligaments

18

What is found in the posterior chamber?

Aqueous humour

19

What is found in the posterior segment of the eye?

Vitreous humour

20

Where is aqueous secreted from?

Ciliary processes

21

What is the circulation of aqueous?

Ciliary body
Then goes into posterior chamber to nourish lens
Then goes into anterior chamber to nourish cornea
It is then reabsorbed at the canal of schlemm

22

What are the 3 parts of the fundus?

Optic disc
Macula
Fovea

23

Where is the point of CN II formation?

Optic disc

24

What is the 'blind spot' caused by?

Optic disc

25

Where is the area of most acute vision?

Fovea

26

Which is thicker on fundoscopy, artery or vein?

Vein

27

What are the 3 layers of the retina? (posterior to anterior)

Photorecptors
Ganglion cells
Axons of ganglion cells

28

Where is light from objects in the right visual field processed?

Left visual cortex

29

Where is light from objects in the lower visual field processed?

Upper part of the primary visual cortex

30

What is the only vein to drain the retina?

Central vein of the retina

31

What is the opthalmic artery a branch of?

Internal carotid artery

32

Where do all of the rectus muscles originate?

Common tendonous ring

33

What is the function of the levator palpebrae superioris?

Lifts upper eyelid

34

Where do the oblique & rectus muscles insert?

Sclera

35

Which nerve supplies the lateral rectus?

CN VI

36

Which nerve supplies the superior oblique?

CN IV

37

Which nerve supplies all the other EO muscles?

CN III

38

What are the only 2 eye muscles to not have a secondary movement?

Medial ~& lateral rectus

39

What effect does the superior rectus have on the eye?

Elevation

40

What effect does the inferior rectus have on the eye?

Depression

41

What effect does the suprior oblique have on the eye?

Depression

42

What effect does the inferior oblique have on the eye?

Elevation

43

What effect does the lateral rectus have on the eye?

Abduction

44

When the eye is abducted with 2 muscles allow elevation & depression?

Superior & inferior rectus

45

What effect does the medial rectus have on the eye?

Adduction

46

Which muscles elevate & depress the eye when in adduction?

Superior & inferior oblique

47

Which muscles are involved in pure elevation?

Superior rectus
Inferior oblique

48

Which muscles are involved in pure depression/

Inferior rectus
Superior oblique

49

In what direction does the zygoma tend to rotate if fractured?

Medially

50

Why does zygomatic fracture cause diplopia?

Suspensory ligament of the ele attaches to the zygoma laterally and injury may result in this being lowered towards the orbital floor

51

What is the suspensory ligament of the eye?

A thick fascial sling that holds the eye just above the floor of the orbit

52

How can orbital trauma cause a general sensory deficit of the facial skin?

Damage to infrrarbital NVB

53

Which nerves supplies the general sensory supply to the upper eyelid, cornea, conjunctiva, skin of the root/bridge/tip of the nose?

CN V1

54

Which nerves supplies the skin of the lower eyelid, the skin over the maxilla, the skin of the ala of the nose, the skin/mucosa of the upper lip?

CN V2

55

Which nerve supplies the skin over the mandible and TMJ?

CN V3

56

Which nerves supply the angle of the mandible?

C2,3 spinal nerves

57

What is involved in the sensory limb of the blink (corneal) reflex?

Action potentials are conducted centrally via CN V1 to the trigeminal ganglion then in CN V to the pons

58

What is involved in the efferent (motor) limb of the blink (corneal) reflex?

Action potentials are conducted peripherally in CN VII to the eyelid part of the orbicularis oculi

59

What is released from the sympathetic presynaptic axon?

Acetylcholine

60

What is released for the sympathetic postsynaptic axon?

Noradrenaline

61

Where do the presynaptic sympathetic axons synapse for supply to the head & neck region?

Cervical sympathetic ganglion

62

What carries sympathetic axons into the orbit?

Ophthalmic artery

63

What is release from the presynaptic axon in the parasympathetic system?

Acetylchholine

64

What is released from the postsynaptic axon in the parasympathetic system?

Acetylcholine

65

Where do all parasympathetic axons leave the CNS?

CN III, VII, IX & X

66

What does CN VII provide parasympathetic innervation to?

Lacrimal gland
Submandibular & sublingual salivary glands
Parotid salivary gland

67

Where does the vagus nerve provide parasympathetic innervation for?

Organs of the neck & chest & abdomen as far as the midgut

68

Where do the sacral spinal nerve carry parasympathetic axons to?

Hindgut
Pelvis
Perineum

69

What does the occulomotor nerve supply somatic motor to?

SR
MR
IR
IO

70

What does the occulomotor nerve supply parasymathetic axons to?

Ciliary ganglion

71

Which nerves control the diameter of the iris and the refractive shape of the lens?

Ciliary nerves

72

What is the oculocardiac reflex?

Reflex bradycardia in response to tension on the extraocular muscles or pressure in the eye (CNS connections between CN V1 & CN X)`

73

Sympathetic functions on the eye

Open eyes wider
Get more light into eyes
Focus on far objects
Emotional lacrimation

74

Parasympathetic functions on the eye

Allow orbicularis oculi to work
Get less light into eyes
Focus on near objects
Reflex lacrimation

75

What type of muscle is the levator palpebrae?

Skeletal & smooth muscle

76

How do axons get from the superior cervical symapthetic ganglion to the obrital structures?

Internal carotid nerve
Internal carotid plexus
Opthalmic artery
Branches to orbital structures

77

What kind of drugs dilate the pupil?

Mydriatic drugs

78

What drugs can cause a pinpoint pupil?

Opiates

79

What is a miotic pupil a compnent of?

Horner's syndrome

80

What is a fixed dilated pupil a pathological sign of?

CN III pathology

81

Whats is the direct light reflex?

Constriction of the pupil that the light is shone in

82

What is the consensual light reflex?

Constriction of the pupil in the non-stimulated eye

83

What the first neurone that pass via the ipsilateral optic nerve to deccusate in the optic chiasm then synapse in the pretectal nucleus in the midbrain?

Retinal ganglion cells

84

Where do the second neurones synapse in the light reflex?

Edinger Westphal nucelus

85

Where do the 3rd neurones in the light reflex synapse?

Ciliary ganglion

86

Where do the 4th neurones in the light reflex travel?

Short ciliary nerves to the sphincter pupillae muscles

87

Does the sphincter muscle contract or relax in far vision?

Relax and flatten

88

Does the ciliary muscle contract or relax when reading a book?

Contract (become spherical)

89

What are the 3 components of the accomodation reflex?

Bilateral pupillary constriction
Bi;atera; convergance
Bilateral relaxation of the lens

90

Which nerve controls the accomodation reflex?

CN III

91

What enzyme within tears helps to clean the cornea?

Lysozyme

92

What is the afferent limb of reflex tears?

CN V1

93

What is the efferent limb of reflex tears?

CN VII