Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Control & Movement > Control L17 visual pathways > Flashcards

Control L17 visual pathways Flashcards

1
Q

What nucleus at the end of the optic tract is involved in the visual pathway?

A

Lateral geniculate body

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Where is the lateral geniculate body found?

A

On the lateral aspect of the thalamus connected to the optic tract

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

How does information from the eyes travel from the lateral geniculate body to the primary visual cortex?

A

Via optic radiations

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

In what lobe is the primary visual cortex?

A

Occipital lobe

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

Where is the primary visual cortex located?

A

In the gyri directly above and below the calcarine sulcus

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

What if he primary visual cortex also known as?

A

Striate area/coretx

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Where does the primary visual cortex extend to?

A

The occipital pole

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Where is the visual association cortex located?

A

Superior to the primary visual cortex posterior to the parietoocipital sulcus and inferior to the primary visual cortex

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

What cells are found in the retina?

A

Photoreceptors

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

What are the three layers of the back of the eyeball?

A

Sclera, choroid and refine (outside —> inside)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

What is the retina?

A

The neural layer of the eye which sends information via the optic nerve to the rest of the visual oathway

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

Where does the optic nerve leave the eye?

A

At the optic disc aka the blind spot

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Why is the optic disc known as the blind spot?

A

As there are no photoreceptors at the optic disc so any light that reaches here is not translated into a signal

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Where is the macula lutea?

A

The back of the eye on the retina in the line of the visual axis

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

How is visual information received at the macula lutea special?

A

it is seen at a higher resolution as highest concentration of photoreceptors.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

What is the fovea?

A

a high concentration of the cone photoreceptors within the macular lutea

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

What are the two layers of the retina?

A

Neuronal
Non-neuronal

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

What cells are in the non-neuronal layer

A

Pigmented epithelium cells

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

What is the function of the non-neuronal layer of the retina?

A

contains melanin to absorb light
Provides nutrients to photoreceptors

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

What cells are found in the neuronal layer of the retina?

A

Cones and rod cells send information from pigmented epithelium to the primary bipolar cells then to the secondary ganglion cells

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

What interneurones are seen between the primary bipolar cells in the retina? What do they do?

A

Horizontal interneurons - modulate transmission
Amacrine interneurons

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

What are more common, rod or cone cells?

A

Rods

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

What is the function of rod cells?

A

Transmit lights and allow vision in dim light

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

What is the function of cone cells?

A

Colour vision and allow high vision acquire

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

How does convergence of rod and cone cells differ?

A

Rod cells = high level
Cones = lower level

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q

What is the relationship between number of cone cells to number of ganglion cells at the macula?

A

1:1

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
27
Q

Why is CN II classed as part of the CNS?

A

As it is an outgrowth of the diencephalon

28
Q

Why can increase in CSF affect the eye?

A

As eye is part of the CNS so has meninges with CSF

29
Q

What is papilloedema?

A

Swelling of the optic disc due to increased CSF pressure causing swelling of the optic nerve compressing the central retinal artery and vein

30
Q

What are symptoms of papilloedema?

A

Headaches
Drowsiness
Blurred vision
Vomiting

31
Q

How many neuron chains are involved in the visual pathway?

A

3

32
Q

How is information sent in the visual oathway?

A

Received by the photoreceptors, pass to bipolar cells, then to ganglion cells which travel through the optic nerve and chiasma and then through the optic tract. It synapses at the optic lateral geniculate nucleus and travels through the optic radiations to the primary visual cortex in the cerebral cortex.

33
Q

How is the visual pathway organised?

A

Retinotopically

34
Q

What is retinotopic organisation?

A

How information from the eye is delivered to the brain

Left half of visual field goes to right hemisphere
Right half of visual field goes to left hemisphere

Upper visual field goes to lower bank of calcarine sulcus
Lower visual field does to upper bank of calcarine sulcus

Information received at macula goes to occipital pole

Thus images at the back of the retina are upside down and mirror reversed

35
Q

How are visual fields separated?

A

Into hemi-fields by a vertical line and then quadrants by a horizontal line

36
Q

What is the centre of the visual field known as?

A

Information that travels to the fovea known as the fixation point

37
Q

What are the two parts of the optic radiations?

A

The inferior trajectory aka Meyer’s loop
Superior trajectory

38
Q

What are the two types of retinal fibres?

A

Nasal (from side of retina closest to the nose)
Temporal (from side of retina closest to temporal lobes)

39
Q

What happens at the optic chiasma?

A

The nasal fibres from the retina cross but NOT the temporal fibres

40
Q

What fibres run in the superior trajectory of the optic radiations?

A

Lower visual field fibres

41
Q

What fibres run in the inferior trajectory (Meyer’s loop) of the optic radiations?

A

Upper visual field fibres

42
Q

Why is information received at the retina upside down to how it is in real life?

A

Upper half of visual field projected to lower aspect of retina so signals travel inferiorly to signals from the lower half of the visual field which is projected to the upper aspect of the retina.

43
Q

What is a scotoma?

A

Localised patch of blindness

44
Q

What is a hemianopia?

A

Half of the visual field is lost

45
Q

What is quadrantanopia?

A

When a quadrant of the visual field is lost

46
Q

What is meant by homonymous?

A

When visual field loss is the same in both eyes

47
Q

What is meant by heteronymous?

A

When visual field loss is different on both eyes

48
Q

How is information received at the retina mapped onto the primary visual cortex?

A

Information from the macula is represented most posteriorly at the occipital pole and as move more peripherally on the retina (from the macula) information is mapped onto the primary visual cortex more anteriorly

49
Q

A 55-year-old woman with a long history of menstrual irregularitiesconsulted with her ophthalmologist, indicating that she wasexperiencing visual disturbances that seemed to have worsenedduring the past couple of months. Her ophthalmologist referredher to a neurologist. A CT scan of the patients head revealed thepresence of a pituitary tumor impinging on the optic chiasma.Which one of the following visual deficits is the patient likely to have?

A. Complete blindness on the left eye
B. Heteronymous (bitemporal) hemianopia
C. Left homonymous hemianopia
D. Inferior left homonymous quadrantanopia
E. Superior right homonymous quadrantanopia with macular sparing

A

B - heteronymous bitemporal hemianopia

50
Q

What is the most common cause of scotomas?

A

Degeneration of cells in retina e.g. macular degeneration

51
Q

True or false, all optic tract fibres travel to the lateral geniculate nucleus?

A

False - only about 90% rest stop at the midbrain

52
Q

What is the pupillary light reflex?

A

The ability of both pupils to respond (constrict/dilate) dependant on the level of light received by the retina

53
Q

What CN are involved in pupillary light reflex?

A

CN II
CN III

54
Q

Where do some optic fibres enter the midbrain?

A

At the level of the superior colliculus into the Pretectal area of the midbrain

55
Q

What nucleus is involved in the pupillary reflex pathway?

A

Edinger-Westphal nucleus

56
Q

What muscle is involved in the papillary light reflex?

A

Sphincter pupillae muscle

57
Q

What ganglion is involved in the pupillary light reflex?

A

Ciliary ganglion

58
Q

What are the two types of pupillary light reflex?

A

Direct = light in one eye causes same pupil to constrict
Consensual = light in one eye causes other pupil to constrict

59
Q

Lesion of what CN causes loss of consensual pupillary eye reflex but intact direct reflex?

A

CN III

60
Q

Lesion of what CN causes loss of both direct and consensual pupillary light reflex?

A

CN II

61
Q

What is the near/accommodation reflex?

A

A series of changes that occur when gaze is transferred from a distant to near object?

62
Q

What happens in the near/accommodation reflex?

A
  1. Accommodation - ciliary muscles contract causing lens to become rounded
  2. Pupil constricted by sphincter pupillae
  3. Ocular convergence by the medial rectus muscle
63
Q

What afferent fibres are involved in the near/accommodation reflex?

A

Optic never and tract
LGN to visual cortex
In CN II

64
Q

What efferent fibres are involved in the near/accommodation reflex?

A

Parasympathetic fibres to sphincter pupillae and ciliary muscles
Motor fibres to medial rectus
All run in CN III

65
Q

Where is CN III stimulated in the near/accommodation reflex?

A

In the midbrain via CN III nuclei

66
Q

Do the fibres from the nasal and temporal hemiretinas travel through the optic radiations contralaterally or ipsilaterally?

A

fibres projecting from nasal hemiretina travel in contralateral optic radiations

fibres projecting from the temporal hemiretina travel in the ipsilateral optic radiation

67
Q

What is the difference between the occulomotor and accessory occulomotor nuclei?

A

occulomotor nucleus = motor pathway
accessory occulomotor nucleus = parasympathetic pathway

Control & Movement (36 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions