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Neuro-Unit 2 > Monday, 4-11-Vision Physiology (Karius) > Flashcards

Monday, 4-11-Vision Physiology (Karius) Flashcards

1
Q

Accomodation requires:

A
  • Ciliary m.
  • Suspensory l.
  • Lens itself
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2
Q

Describe the process of near vision regarding ciliary muscle, suspensory ligament and the shape of the lens:

A

Ciliary muscle contracts –> suspensory ligament tension decreased –> lens becomes rounder –> increased curvature of lens increases refractive power of the lens

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3
Q

Describe the process of far vision regarding the ciliary muscles, suspensory ligaments, and the shape of the lens:

A

Ciliary muscle relaxes –> tension on suspensory ligament increases –> lens pulled FLAT –> decreased curvature of lens decreases refractory power

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4
Q

The NEAR VISION response requires:

A
  • Contraction of ciliary muscles
  • Convergence of eyes to the point of focus
  • Constriction of the pupil –> constricting pupil reduces opening for light to enter, eliminates some of diverging light rays, allows to focus better
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5
Q

These cell types have a direct pathway to the optic nerve to the brain:

A
  • photoreceptors (rods and cones)
  • bipolar cells
  • ganglion cells

Horizontal and amacrine cells do their processing in the retina to increase signal fidelity

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6
Q

The VERTICAL PATHWAY of the retina is composed of these cells:

A
  • Photoreceptor (rod or cone)
  • Bipolar cell
  • Ganglion cell
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7
Q

Regarding the VERTICAL PATHWAY of the retina, the photoreceptors have a constant release of glutamate. When it is dark (no stimulation), the release of glutamate is __. When a photon activates the photoreceptor, the release of glutamate __

A

High

Decreases

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8
Q

Regarding the vertical pathway for cones:

  • Step 1: A photoreceptor is struck by a photon of light
  • Step 2: decrease NT release onto a __ cell and the NT is __
A
  • BIPOLAR

- GLUTAMATE

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9
Q

Regarding the ON-center bipolar cells:

Activation of a photoreceptor in the center of the bipolar cell’s receptive field causes __ of the bipolar cell

Activation of a photoreceptor in the surrounding region causes ___ of the bipolar cell

A

Depolarization

Hyperpolarization

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10
Q

Regarding the OFF-center bipolar cells:

Activation of a photoreceptor in the center of the bipolar cell’s receptive field causes ___ of the bipolar cell

Activation of a photoreceptor in the surrounding region causes __ of the bipolar cell

A

Hyperpolarization

Depolarization

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11
Q

Regarding the VERTICAL PATHWAY for cones:

If the photoreceptor activates an ON-center bipolar cell, a __ receptor is activated and NT release causes a __ in cation influx

A

Metabotropic

Decrease

-Activation of the photoreceptor decreases NT release; So in the dark, the ON-center cell is hyperpolarized and with light, release of Glu from the photoreceptor decreases so the cation current increases and the ON-center cell is depolarized

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12
Q

Regarding the VERTICAL PATHWAY for cones:

If the photoreceptor activates an OFF-center bipolar cell, an __ receptor is activated and NT release causes a __ in cation influx

A

AMPA

Increase

-Activation of the photoreceptor DECREASES NT release; so in the dark, the OFF-center cell is depolarized and with light, Glu release from the photoreceptor decreases, the AMPA receptor is not activated and the OFF-center cell is hyperpolarized

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13
Q

___ cells are ON-center or OFF-center cells (whatever the connecting bipolar cell is)

A

Ganglion

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14
Q

In the VERTICAL PATHWAY for cones, the bipolar cell releases __ to excite the ganglion cell. The ganglion cell axons become the fibers for the __.

A

Glutamate

Optic n.

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15
Q

In the VERTICAL PATHWAY for RODS, many rods converge on 1 ON-center bipolar cell –> synapse on an __ cell –> which synapses on a CONE ON-center bipolar cell –> which activates a ganglion cell

A

A11 amacrine cell

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16
Q

The ON- and OFF-center cells help us increase the ability to detect edges and so they sharpen our vision. The __ cell tells us where something is while the ___ cell tells us where it ends.

A

ON-center

OFF-center

-Amacrine and horizontal cells add to this by providing INHIBITORY signals that modify the activity of neighboring photoreceptors, bipolar cells, or ganglion cells

17
Q

Action potentials occur in ___ cells which become the fibers of the optic nerves.

A

Ganglion cells

18
Q

The LEFT TEMPORAL RETINA is activated by light coming from the __ visual field

The LEFT NASAL RETINA is activated by light coming from the ___ visual field

A

Right

Left

19
Q

The RIGHT TEMPORAL RETINA is activated by light coming from the ___ visual field

The RIGHT NASAL RETINA is activated by light coming from the ___ visual field

A

Left

Right

20
Q

At the optic chiasm, the axons from the __ on each side will cross and join the axons from the temporal retina. This way ALL the info from the right visual field is sent to the same part of the brain

A

Nasal retina

21
Q

Visual inputs arising from the optic tract synapse in the ___

A

Lateral geniculate body

22
Q

The functions of the __ consist of controlling motion of the eyes (convergence/divergence), control focusing so that the image we are interested in is in the best focus possible, ID the major elements within our visual image and send the ID to the cortex, and ID motion within our visual image

A

Lateral geniculate body

23
Q

V1 is known as the ___ cortex

A

Primary visual

24
Q

Which layer(s) of the primary visual cortex (V1) are responsible for the following?:

___ allow networking between V1 and other parts of the cortex
___ receives inputs from the LGN
___ send information BACK to the LGN

A

Layers 1,2,3

Layer 4

Layers 5 and 6

25
Q

There are a lot of columns in V1 that receive input from photoreceptors in the ___ in part because that is the place where receptor density is greatest

The __ regions of the retina have much less area in V1 devoted to them (few receptors, many of which converge onto the same bipolar cells)

A

Macula

Peripheral

26
Q

The major job of ___ is to IDENTIFY THE EDGES/CONTOURS of the components in our visual image

A

V1

27
Q

The major job of __ is to IDENTIFY DISPARITIES IN VISUAL IMAGES PRESENTED BY 2 EYES. Also used for DEPTH PERCEPTION

A

V2

28
Q

Within the columns, there collections of neurons known as ‘blobs’ that enable color detection. Accurate color detection depends on the input from __

A

All 3 sets of cones

29
Q

The major job of __ appears to be COMPLETE PROCESSING OF THE COLOR INPUTS

A

V4

30
Q

The __ pathway leaving the occipital cortex relays visual information to the motor cortices and enables us to complete motor acts based on visual input. This path allows you to play catch with your friends

A

Dorsal

31
Q

The __ pathway relays visual information to areas of the brain involved in higher processing of sensory inputs. The integration of the visual input with other sensory inputs allows us to use that visual image to accomplish higher order functions, including naming the object and copying the object

A

Ventral

32
Q

Copying an object and naming/recognizing it are separate functions and damage to the __ lobe can selectively impair one without hindering the other. Similar or related objects are all coded for in localized regions of the __ lobe.

A

Temporal

Temporal

33
Q

The __ is the first site in the eye where refraction occurs. It bends the light the most of any structure in the eye and accounts for 2/3 of the ability of the eye to bend light.

A

Cornea

Neuro-Unit 2 (11 decks)

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