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Head, Neck and Neurological Systems > Week 6 > Flashcards

Week 6 Flashcards

1
Q

Briefly outline the visual pathway from eyes to brain

A

Eyes → optic nerves → optic chiasm → optic tracts → optic radiations

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2
Q

Where are images of the right external environment relayed to?

A

Left side of the back of the eye

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3
Q

What is the result of optic nerve damage?

A

Loss of vision in that eye

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4
Q

What is the result of optic chiasm damage?

A

Crossing fibres are affected which causes loss of outer part of visual field of each eye

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5
Q

What could be the cause of optic chiasm damage?

A

Pituitary tumour compressing the chiasm

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6
Q

What is the result of optic radiation or cortical damage?

A

Loss of vision on opposite side to lesion

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7
Q

What does the red test look for?

A

Relative field defect

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8
Q

What does the finger movement test look for?

A

Absolute field defect

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9
Q

What is hemianopia?

A

Loss of vision on one side

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10
Q

What can cause hemianopia?

A

Ischaemia due to blockage of posterior or middle cerebral artery

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11
Q

What does homonymous mean?

A

Of the same distribution on both sides

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12
Q

What are the signs of homonymous hemianopia?

A

Complaint of poor vision with normal visual acuity
Bumping into objects
Stroke with movement problems on one side

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13
Q

What is the normal pupil response to light?

A

Rapid constriction of pupil to light (direct) and simultaneous constriction of other pupil (consensual)

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14
Q

Briefly outline the pathway of the pupil response

A

Light shone in one eye → signal passed down optic nerve → splits in chiasm → passes down both sides to upper tectal region of midbrain → passed to CN 3 on both sides → causes constriction of both pupils

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15
Q

What part of the visual pathway is affected by optic nerve, optic chiasm and optic radiations damage?

A

Nerve - clarity, pupil
Chiasm - visual fields
Radiations - homonymous

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16
Q

What part of the brain receives visual information?

A

Primary visual cortex/V1/striate cortex

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17
Q

How does light interact with the retina?

A

Deepest layers of retina (photoreceptors) receive light first; back-to-front mechanism

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18
Q

Approximately how long is the optic nerve?

A

50mm

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19
Q

How many optic fibres decussate at the optic chiasm?

A

50-60%

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20
Q

What is the LGN?

A

Lateral geniculate nucleus

Relay centre of the thalamus, alternating white and grey matter, 6 layers

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21
Q

What is the superior colliculus?

A

Area of the midbrain involved in control of eye movement to track a moving stimulus

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22
Q

Where is the pituitary stalk in relation to the optic chiasm?

A

Underneath

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23
Q

Where can optic fibres project?

A

LGN
Superior colliculus
Pretectal area

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24
Q

Input to which part of the retina will always cross over?

A

Nasal retina

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25
Q

What defect results from a partial optic nerve lesion?

A

Ipsilateral scotoma

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26
Q

What defect results from a complete optic nerve lesion?

A

Blindness in that eye

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27
Q

What defect results from an optic chiasm lesion?

A

Bitemporal hemianopia

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28
Q

What defect results from an optic tract lesion?

A

Homonymous hemianopia

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29
Q

What defect results from a Meyer’s loop lesion?

A

Homonymous upper quadrantanopia

30
Q

What is Meyer’s loop?

A

Part of the optic radiation which sweeps back on itself into the temporal lobe, just lateral to the temporal horn of the lateral ventricle

31
Q

What defect results from an optic radiation lesion?

A

Homonymous hemianopia

32
Q

What defect results from a visual cortex lesion?

A

Homonymous hemianopia

33
Q

What defect results from a bilateral macular cortex lesion?

A

Bilateral central scotoma

34
Q

What can cause optic nerve lesions?

A

Acute optic neuritis
Multiple sclerosis
Indirect traumatic optic neuropathy
Optic atrophy

35
Q

What can cause optic chiasm lesions?

A

Tumours (pituitary adenoma, meningioma)

Aneurysms (ACA)

36
Q

What can cause optic tract lesions?

A

Tumours
Trauma
Aneurysm of posterior cerebral artery

37
Q

What is Goldmann perimetry?

A

Assesses the extent of visual field
A test light is used as the stimulus (kinetic or static) and visual field can be mapped according to detection of the light

38
Q

What is the pupillary light reflex?

A

Pupil constriction in response to light

39
Q

What is the accommodation reflex?

A

Pupil constriction and convergence of the eyes when looking from a distant object to a close one

40
Q

Is pupil constriction under sympathetic or parasympathetic control?

A

Parasympathetic

41
Q

What is the pathway for pupil constriction?

A

Edinger-Westphal nucleus → ciliary ganglion → eye

42
Q

What is the pathway for pupil dilation?

A

Spinal cord → superior cervical ganglion → eye

43
Q

Is pupil dilation under sympathetic or parasympathetic control?

A

Sympathetic

44
Q

What nerves are involved in the afferent and efferent pathway of the pupillary light reflex?

A

Afferent - optic nerve

Efferent - occulomotor

45
Q

Briefly outline the pathway of the pupillary light reflex

A

Light shone in right eye → information from right eye reaches pretectal nuclei on right and left → both Eddinger-Westphal nuclei activated → right and left oculomotor nerves activated → constriction of both pupils

46
Q

What is hippus and when might it be seen?

A

Initial dilation/oscillation in response to light which is normal and can be found in some healthy young people

47
Q

What is the swinging flashlight test?

A

Test to identify asymmetry of afferent input in the pupillary light reflex (called a relative afferent pupil defect (RAPD))

48
Q

What can cause a RAPD?

A

Optic neuritis

Large retinal detachment

49
Q

What would be seen in an abnormal swinging flashlight test?

A

When moving the light source from the right to left eye, the left eye paradoxically dilates (problem with left eye afferent limb)

50
Q

What are the 3 components of the accommodation-convergence reflex and what muscles are responsible for each?

A 
Pupil constriction (constrictor pupillae)
Lens accommodation (ciliary muscles)
Convergence of eyes (medial rectus muscles)
51
Q

What is the stimulus in the accommodation-convergence reflex test?

A

Out-of-focus image

52
Q

What nerves constitute the afferent and efferent limbs of the accommodation-convergence reflex?

A

Afferent - optic nerve

Efferent - oculomotor nerve

53
Q

How are the pupils clinically examined?

A
  1. Inspect (irregularity/asymmetry)
  2. Direct and consensual light response
  3. Swinging light test
  4. Accommodation-convergence reflex test
54
Q

What is the Edinger-Westphal nucleus?

A

Accessory oculomotor nucleus

Parasympathetic pre-ganglionic nucleus that innervates the iris sphincter muscle and the ciliary muscle

55
Q

What is the calcarine sulcus a landmark for?

A

Marks primary visual cortex within the superior and inferior calcarine gyri

56
Q

What is the superior colliculus also known as?

A

Tectum

57
Q

What cranial nerves pass through the venous cavernous sinus?

A

Oculomotor
Trochlear
Abducens

58
Q

What percentage of brain tumours are anaplastic astrocytomas?

A

80%

59
Q

What cranial nerve is affected by suprasellar meningioma?

A

Oculomotor nerve

60
Q

What signs indicate that the oculomotor nerve has been compromised?

A

Fixed and dilated pupil

61
Q

What epithelium lines the air sinuses of the skull?

A

Respiratory epithelium

62
Q

What mneumoic can be used to determine what cranial nerves are sensory and/or motor in order?

A

Small ships make money but my brother says big boats make more

63
Q

What piece of equipment is required for a fundoscopy?

A

Ophthalmoscope

64
Q

What is the red reflex?

A

Reddish-orange reflection of light from the back of the eye observed when using an ophthalmoscope

65
Q

What vascular arcades are found in the eye?

A

Retinal - superior and inferior

66
Q

How can veins and arteries in the eye be distinguished?

A

Arteries - thin and bright

Veins - thick and dark

67
Q

How would you check the macula during a fundoscopy?

A

Ask the patient to look directly into the light

68
Q

How are facial injuries classified?

A

Le Fort I (lower)
Le Fort II (middle)
Le Fort III (upper)

69
Q

What Le Fort classifications are associated with base of skull fractures?

A

II and III

70
Q

How might surgeons use hyaluronic acid?

A

Lip fillers

Scar reduction

Head, Neck and Neurological Systems (6 decks)

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