Brainscape's Knowledge GenomeTM

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


See full index

Neuro Exam 2 > Vision Physiology II > Flashcards

Vision Physiology II Flashcards

1
Q

Retina is the ___ _______ portion of the eye

A

Retina is the light sensitive portion of the eye

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

The retina

  • Contains ____ for color vision
  • Contains _____ for night vision
  • Contains ____ _______
A

The retina

  • Contains cones for color vision
  • Contains rods for night vision
  • Contains neural architecture
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Melanin is located in the ____ layer of the retina

A

pigmented

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

Melanin prevents ____ _____ and stores ______

A

Melanin prevents light reflection and stores Vitamin A

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

Vitamin A is exchanged back and forth through the ___ ______ of the ____ segments of the rods and cones

A

Vitamin A is exchanged back and forth through the cell membranes of the outer segments of the rods and cones

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

What is a precursor to photosensitive chemicals of the rods and cones?

A

vitamin A

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

Fovea is a small area at the____of the retina (1 sq mm) that is capable of ___ and ____vision.

A

Fovea is a small area at the center of the retina (1 sq mm) that is capable of acute and detailed vision.

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

The center of the fovea (central fovea) contains only ____

A

The center of the fovea (central fovea) contains only cones

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

What is the area of greatest acuity?

A

the central fovea

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

Major functional segments of rods or cones:

  • Outer segment: ____ ______photochemical
  • Inner segment: ____ _____
  • Nucleus
  • Synaptic body: connects to subsequent _____cells
A

Major functional segments of rods or cones:

  • Outer segment: light sensitive photochemical
  • Inner segment: cytoplasmic organelles
  • Nucleus
  • Synaptic body: connects to subsequent neuronal cells
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

žRods and cones contain chemicals that_____ on exposure to light. This ____ the nerve fibers leading from the eye.

A

žRods and cones contain chemicals that decompose on exposure to light. This excites the nerve fibers leading from the eye.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q
  • When light is absorbed by _____ it immediately begins to decompose
  • In the process of splitting away a number of ____ _____ are formed
  • _________ excites the rods forming ____ _____ of the optic nerve and transmission of the visual image into the CNS
A
  • When light is absorbed by rhodopsin it immediately begins to decompose
  • In the process of splitting away a number of intermediary compounds are formed
  • Metarhodopsin II excites the rods forming action potential of the optic nerve and transmission of the visual image into the CNS
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Reformation of rhodopsin:

  • Rhodopsin is broken down into _____+ ______
  • Metabolic energy converts all-trans retinal to _______, catalyzed by_________
  • 11-cis retinal automatically recombines with _______ to form rhodopsin
A

Reformation of rhodopsin:

  • Rhodopsin is broken down into all-trans retinal + scotopsin
  • Metabolic energy converts all-trans retinal to 11-cis retinal, catalyzed by retinal isomerase
  • 11-cis retinal automatically recombines with scotopsin to form rhodopsin
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Role of vitamin A for the formation of rhodopsin:

  • All-trans retinal conversion to _______(form of Vitamin A)
  • All-trans retinol converted to______
  • Catalyzed by ______
  • 11-cis retinol converted to ______which can combine with scotopsin to form new rhodopsin
A

Role of vitamin A for the formation of rhodopsin:

  • All-trans retinal conversion to all-trans retinol (form of Vitamin A)
  • All-trans retinol converted to 11-cis retinol
  • Catalyzed by isomerase
  • 11-cis retinol converted to 11-cis retinal which can combine with scotopsin to form new rhodopsin
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

žRods under No light conditions=______

žOuter segment of rod:

  • _____-gated channels allow influx of _____
  • In the dark, cGMP levels are _____

žInner segment of rod:

  • _____pump
  • ___- leak channels

ž-____ mV is resting state

žReduced _____

A

žRods under No light conditions=DARK CURRENT

žOuter segment of rod:

  • cGMP-gated channels allow influx of Na+
  • In the dark, cGMP levels are high

žInner segment of rod:

  • Na/K pump
  • k- leak channels

ž-40 mV is resting state

žReduced electronegativity

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

žRods under LIGHT conditions:

  • ž_____ in the outer segment is exposed to light, becomes activated, and decomposes
  • žcGMP-gated sodium channels ____
  • ž____ influx of Na+
  • žNa+ continues to be pumped via ____ pump from ____ ____
  • žMore Na+ ____

žIncreased Negativity: ______

A

žRods under LIGHT conditions:

  • žRhodopsin in the outer segment is exposed to light, becomes activated, and decomposes
  • žcGMP-gated sodium channels close
  • žReduced influx of Na+
  • žNa+ continues to be pumped via Na/K pump from inner segment
  • žMore Na+ leaves

žIncreased Negativity: HYPERPOLARIZATION

17
Q

Mechanism for Light to Decrease Sodium Conductance

  1. Light activates______
  2. Stimulates _______
  3. Transducin activates ______ that breaks down cGMP
  4. Reduced cGMP ____ cGMP-gated sodium channels
  5. Photoreceptors _____
A

Mechanism for Light to Decrease Sodium Conductance

  1. Light activates Rhodopsin
  2. Stimulates G-protein transducin
  3. Transducin activates cGMP PDE that breaks down cGMP
  4. Reduced cGMP closes cGMP-gated sodium channels
  5. Photoreceptors hyperpolarize
18
Q

žWhat is responsible for keeping Na+ channel in the outer segment of the rods open?

A

cGMP

19
Q

Light activated rhodopsin activates what?

A

žG-protein transducin

20
Q

What deactivates the activated rhodopsin?

A

rhodopsin kinase

21
Q

žReceptor potential is proportional to the logarithm of the ____ ______

•Very important for discrimination of the ____ _____

A

žReceptor potential is proportional to the logarithm of the light intensity

•Very important for discrimination of the light intensity

22
Q

žthe sensitivity of the retinal automatically adjusts to the __ ____

A

žthe sensitivity of the retinal automatically adjusts to the light level

23
Q

žColor vision is the result of activation of ____

A

cones

24
Q

What are the three types of cones?

A

blue, green, and red

25
Q

What is the protein that exists in cones?

A

Photopsin

26
Q

Color blindness

  • Lack of a particular type of _____
  • žGenetic disorder passed along on the ______
  • žOccurs almost exclusively in _____
  • žMost color blindness results from lack of the ___ or ____ cones
  • •Lack of ____cone, protanope
  • •Lack of _____ cone, deuteranope
A

Color blindness

  • žLack of a particular type of cone
  • žGenetic disorder passed along on the X chromosome
  • žOccurs almost exclusively in males
  • žMost color blindness results from lack of the red or green cones
  • •Lack of red cone, protanope
  • •Lack of green cone, deuteranope
27
Q

žtransmit signals in the outer plexiform layer and synapse with bipolar cells and horizontal cells

A

rods and cones

28
Q

žtransmit signals horizontally in the outer plexiform layer from rods and cones to bipolar cells

A

horizontal cells

29
Q

žtransmit signals vertically from rods, cones, and horizontal cells to the inner plexiform layer and synapse with ganglion cells and amacrine cells

A

bipolar cells

30
Q

žtransmit signals from bipolar cells to ganglion cells

A

amacrine cells

31
Q

žtransmit output signals from the retina through the optic nerve into the brain

A

ganglion cells

32
Q

žELECTRONIC CONDUCTION (signal transduction in retina)

  • Direct flow of ____ _____, NOT action potential
  • Always ____ _____proportional to _____ ____
  • The only cells that have action potentials are_____ cells

–Send signals all the way to the brain

A

žELECTRONIC CONDUCTION (signal transduction in retina)

  • Direct flow of electric current, NOT action potential
  • Always graded response proportional to light intensity
  • The only cells that have action potentials are ganglion cells

–Send signals all the way to the brain

33
Q

žRods and cones release _____

A

glutamate

34
Q

_____ cells release aminobutyric acid, glycine, dopamine, acetylcholine and indolamine

A

amacrine cells

35
Q

Output of horizontal cells is always _____

A

inhibitory

36
Q

Horizontal cells prevent the lateral spread of light excitation on the retina, which is called

A

lateral inhibition

37
Q

Horizontal cells have an ____center and an____ surround, which is essential for transmitting _____borders in the visual image.

A

Horizontal cells have an excitatory center and an inhibitory surround, which is essential for transmitting contrast borders in the visual image.

38
Q

Three types of ganglion cells:

žW cells (40%) receive most of their excitation from ____cells; sensitive to ____ ____ in the visual field

žX cells (55%) ___ receptive field, ____ retinal locations, may be responsible for the ____ of the visual image itself, always receives input from at least one ____, may be responsible for _____ transmission

žY cells (5%) ___receptive field respond to____ _____ in the visual field

A

Three types of ganglion cells:

žW cells (40%) receive most of their excitation from rod cells; sensitive to direction movement in the visual field

žX cells (55%) small receptive field, discrete retinal locations, may be responsible for the transmission of the visual image itself, always receives input from at least one cone, may be responsible for color transmission

žY cells (5%) large receptive field respond to instantaneous changes in the visual field

Neuro Exam 2 (18 decks)

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