Brainscape's Knowledge GenomeTM

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


See full index

Medical Studies 2A > 4.2 Vision > Flashcards

4.2 Vision Flashcards

You may prefer our related Brainscape-certified flashcards:
USMLE® Step 1 flashcards
1
Q

What structures are located in the anterior segment of the eye? What delineates this boundary?

A
  • Cornea
  • Iris
  • Ciliary body
  • Lens

(Everything in front of vitreous humor)

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

What are the boundaries of the anterior and posterior chambers of the anterior segment of the eye?

A

Anterior: from posterior cornea to iris

Posterior: from iris to vitreous humour

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

What membrane separates the vitreous humor from the rest of the eye?

A

Vitreous membrane

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

What is contained in the posterior segment of the eye?

A
  • Vitreous humor
  • Retina
  • Choroid
  • Optic nerve
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

What is the limbus of the eye?

A

The boundary between the cornea and the sclera

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

Is the choroid thickest at the back or the front of the eye? Why does this make sense?

A
  • Thicker at back
  • More blood supply needed as there are more retinal cells in this area
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

What are the three anatomical “tunics” of the eye?

A
  • Fibrous tunic (sclera and cornea)
  • Vascular tunic (choroid, iris, ciliary body)
  • Nervous tunic (retina)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

What is the structure and function of the sclera?

A

Structure: white part of eye. Made of fibrous connective tissue.

Function: Protects eye and provides attachment for extraocular muscles.

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

What is the function of the cornea?

A
  • Focuses light as it enters the eye
  • Also protects the rest of the eye from the external environment
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

What is the function of the iris?

A

Mediates how much light enters the eye

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

What is the specific function of the lens of the eye?

A

Focuses light onto retina

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

What are the functions of the ciliary body of the eye?

A
  • Accommodation (changes lens shape)
  • Aqueous humor production/resorption
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

By what structures are the ciliary bodies connected to the lens of the eye?

A

Fibres called zonules (AKA suspensory ligaments)

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

What is the function of aqueous humor?

A
  • Provide nutrients to eye
  • Carry away waste

(Basically blood)

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

What enters and exits the eye at the optic disc?

A
  • Optic nerve
  • Retinal blood vessels
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

This region lies in the middle of the retina, and light is focused onto it by the cornea and lens…

A

The macula

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

This region is a dark spot in the centre of the macula where the retina is thinnest…

A

Fovea

18
Q

The ____ the density of cones, the more acute the vision.

A

Higher density cones = more acute vision

19
Q

What ARE rods and cones? (One word answer)

A

Photoreceptors

20
Q

Differentiate between the rods and cones of the eye

A

Rods: low acuity, high sensitivity, dark vision

Cones: high acuity, low sensitivity, bright vision, colour vision

21
Q

Are there more rods or cones in the eye?

A

Rods, by 20 : 1

22
Q

We have three different types of cones in our eyes, each of which expresses a different colour pigment. What are the three pigments?

A
  • Red
  • Green
  • Blue

(RGB colour system)

23
Q

Describe the distribution of rods and cones in the retina

A

Everywhere except fovea: many rods, few cones.

Fovea: many cones, few rods

24
Q

Describe the three layers of cells in the retina of the eye

A

Furthest back: photoreceptors (rods and cones)

Middle: bipolar cells

Furthest forward: ganglion cells (form optic nerve)

25
Q

This kind of interneuron is able to control the messages between photoreceptors and bipolar cells…

A

Horizontal cells

26
Q

This kind of interneuron is able to control messages between bipolar cells and ganglion cells…

A

Amacrine cells (a macr ine = non long fibre)

27
Q

80% of the focusing of light in the eye happens at the level of the…

A

Cornea

28
Q

Describe the physics of how accommodation enables us to see stuff close up

A
  • Close vision = ciliary muscle contracts
  • Suspensory ligaments loosen
  • Lens is less stretched (therefore thicker)
  • Light has to pass through more lens -> refracts more
  • Sharper bending enables light to hit the retina at the right point
29
Q

What to proteins are found in visual pigment in the photoreceptors of the eye?

A
  • Retinal
  • Opsin
30
Q

Describe the intracellular signalling cascade that enables photoreceptors to function

A
  • Light hits retinal -> causes shape change
  • Shape change increases transducin activity
  • Cascade, resulting in activation of enzyme known as phosphodiasterase
  • Closes Na+ channels
  • No more transmitter release -> inhibiting inhibition of bipolar cells
  • AP fires from bipolar cells

SIMPLIFIED VERSION:
- Light hits retinal pigment
- Intracellular signalling cascade
- Closes Na+ channels = no more depolarisation
- No more inhibition of ganglion cells = signal transmission

31
Q

What would be the consequence of a lesion in the optic chiasm?

A

Bitemporal hemianopia

32
Q

What are the three sites of termination of the optic tract?

A
  • Lateral geniculate nucleus of thalamus (most)
  • Superior colliculus
  • Pretectal nucleus (for light reflexes and accomodation reflex)
33
Q

What is caused by damage to the optic tract?

A

Homonymous hemianopia

34
Q

What are the superior colliculus visual field projections important for?

A

Orienting eyes in response to new stimuli

35
Q

Which eye (ipsi/contra) is represented in each of the six layers of the lateral geniculate nucleus?

A

Ipsi: 2, 3, 5
Contra: 1, 4, 6

36
Q

What does damage to one of the lateral geniculate nucleus cause?

A

Patchy homonymous hemianopia

37
Q

Where do fibres from the inferior vs superior optic radiations terminate?

A

Superior: cuneus
Inferior: lingula

38
Q

Is V1 located medially or laterally in the brain?

A

Medially

39
Q

Name the two sections of the occipital lobe on either side of the calcarine fissure

A

Superior: cuneus
Inferior: lingula

40
Q

Describe the “what” stream: which lobe and cortex is it associated with, and what is it important for?

A
  • Temporal lobe
  • Occipitotemporal association cortex
  • Analyses form, faces, letters etc.
41
Q

Describe the “where” stream: which lobe and cortex is it associated with, and what is it important for?

A
  • Parietal lobe
  • Parieto-occipital association cortex
  • Important for analysing motion and spatial relationships

Medical Studies 2A (110 decks)

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