4 - Retina + central visual pathways Flashcards Preview

Semester 5 - Neuro > 4 - Retina + central visual pathways > Flashcards

Flashcards in 4 - Retina + central visual pathways Deck (30):
1

Name the 2 main layers of the retina:

1) Retinal pigment epithelium
2) Neural layer

2

What is the function of the retinal pigment epithelium?

- Melanocytes absorb scattered light entering retina to protect against photooxidation of macula cells
- Transport nutrients to retinal visual cells

3

Why do albinos have problems seeing in bright sunlight?

- Retinal pigment epithelium is not pigmented (no melanin), so light entering retina is not dampened down = damaged macula cells

4

What are the 3 main types of cells in the neural layer of the retina?

1) Photoreceptor cells: rods and cones
2) Bipolar cells
3) Ganglion cells

5

Name the 2 main ways to view the retina:

1) Fundoscopy
2) Optical Coherence Tomography

6

Total blindness of one eye:
- where is the lesion?
- name some common causes:

Optic nerve
- Optic nerve glioma/meningioma
- Trauma
- Retinoblastoma

7

Bitemporal hemianopia:
- where is the lesion?
- name some common causes:

Optic chiasm
- Pituitary adenoma
- ACA aneurysm

8

Left homonymous hemianopia:
- where is the lesion?
- name some common causes:

Right optic tract
- Neoplasia
- Stroke
- Trauma

9

Left inferior homonymous quadrantonopia:
- where is the lesion?
- name some common causes:

Right superior parietal radiations
- Neoplasia
- Stroke
- Trauma

10

Right superior homonymous quadrantonopia:
- where is the lesion?
- name some common causes:

Left inferior temporal radiations (Meyer's loop)
- Neoplasia
- Stroke
- Trauma

11

Left homonymous hemianopia with macula sparing:
- where is the lesion?
- what is the cause?
- why is the macula spared?

Right primary visual cortex (occipital lobe)
- Stroke in posterior cerebral artery
- Macula is supplied by MCA

12

Which nucleus is involved in the visual pathways?

Lateral geniculate nucleus

13

What is amaurosis fugax?
Name some common causes:

Sensation of 'black curtain' falling over 1 or both eyes temporarily
- TIA
- Giant cell arteritis
- Papilloedema
- MS

14

A pituitary adenoma can compress the optic chiasm. What visual change would this cause?

Bitemporal hemianopia

15

What visual change is associated with a stroke in the posterior cerebral artery?

Contralateral homonymous hemianopia with macular sparing

16

What is the function of the Medial Longitudinal Fasciculus?

Yokes the medial movement of one eye to the lateral movement of the other eye during lateral gaze

17

What is internuclear ophthalmoplegia?

Medial longitudinal fasciculus is damaged, so lateral gaze no longer linked
= abducting eye can move, but adducting eye cannot follow

18

What are some causes of internuclear ophthalmoplegia?

- MS
- Brainstem stroke
- Pontine glioma

19

A patient has a tumour arising from the right cavernous sinus and invading medially towards the optic chiasm. Which visual field defect might this result in?

Unilateral right nasal hemianopia

20

Destruction of the optic tract is rare. What would be the consequence of compression of the right optic tract?

Left homonymous hemianopia

21

Homonymous superior quadrantanopia is most commonly seen in lesions to which part of the visual pathway?

Meyer’s loop (inferior temporal optic radiation)

22

Which geniculate nucleus is involved in the visual pathway?

Lateral geniculate nucleus

23

Which geniculate nucleus is involved in the auditory pathway?

Medial geniculate pathway

24

Depolarisation of hair cells in the auditory pathway is dependant on the influx of which ion?

K+

25

Name some common causes of conductive hearing loss:

- Blocked EAM
- Ruptured tympanic membrane
- Otitis media
- Otosclerosis
- Rubella

26

Name some common causes of sensorineural hearing loss:

- Gentamicin toxicity
- Trauma
- Age-related loss
- Acoustic neuroma
- Tinnitus
- Congenital
- Neuropathy ie hyperbilirubinaemia

27

What are the 3 most common causes of vertigo?

1) BPV = Benign Paroxysmal positional vertigo
2) Acute labyrinthitis
3) Meniere's disease

28

In which lobe is the auditory cortex?

Temporal lobe

29

Otitis media causes which type of hearing loss?

Conductive loss

30

Hyperbilirubinaemia can cause which type of hearing loss?

Sensori-neural (neuropathy)