Vision

Question 1

Refraction

Answer 1

Bending of light rays

Question 2

Vision Process

Answer 2

1. Light is focused through the lens
2. The cornea bend light rays and focuses the image on the retina
3. Focus is adjusted by changes in the shape of the lens
4. Rods and Cones are activated, releasing NT molecules
5. Triggers Bipolar Cells that connect with Ganglion Cells
6. Axons form the optic nerve that carry information to the brain
7. Either the Scotopic or Photopic System is activated
   - Scotopic (Rods): Rhodpsin is hit by light it triggers G protein transducin, causing sodium ion channels to close creating a hyperpolarization

Question 3

Ciliary Muscles

Answer 3

Control the shape of the lens

Question 4

Pupil

Answer 4

Controls the amount of light that enters the eye

Question 5

Extraocular Muscles

Answer 5

Extend from the outside of the eyeball.

Fixating still or moving targets require control of these muscles

Question 6

Bipolar Cells

Answer 6

Located in the retina and receive information from rods and cones and pass the information to retinal ganglion cells.

Question 7

Ganglion Cells

Answer 7

A class of cells in the retina whose axons form the optic nerve

Question 8

Horizontal Cells

Answer 8

Contact both the receptor cells and the bipolar cells

Question 9

Amacrine Cells

Answer 9

Contact both the bipolar cells and the ganglion cells

Especially significant in inhibitory interactions within the retina

Question 10

Rods, Cones, Bipolar Cells, and Horizontal Cells generate…

Answer 10

Local potentials

Question 11

Ganglion Cells generate…

Answer 11

Action potentials

Question 12

Scotopic System

Answer 12

Operates with rods and works in dim light

Question 13

Photopic System

Answer 13

Operates at high levels of light, shows sensitivity to color and involves the cones

Question 14

Rods

Answer 14

Work in dim light
Contain Rhodopsin
Concentrated in the periphery of the retina

Question 15

Cones

Answer 15

Work to distinguish colors
Contain Opsin
Concentrated in the fovea

Question 16

The size of the hyperpolarizing photoreceptor potential determines…

Answer 16

how much less synaptic transmitter will be released

Question 17

The process required to stimulate the visual receptors helps account for…

Answer 17

Sensitivity
Integration
Adaption

Question 18

Photoreceptor adaptation factors

Answer 18

Varying concentration of calcium ions

The recombination of retinal and opsin

Question 19

There are no photoreceptors in the..

Answer 19

Optic Disc

Question 20

Rods provide…

Answer 20

High sensitivity with limited acuity

Question 21

Cones provide…

Answer 21

High acuity with limited sensitivity

Question 22

Lateral Inhibition

Answer 22

Interconnected neurons inhibit their neighbors, producing contrast at the edges of regions

Question 23

Optic Chiasm

Answer 23

The point at which the two optic nerves meet

Question 24

Lateral Geniculate Nucleus

Answer 24

The part of the thalamus that receives information from the optic tract and sends it to visual areas in the occipital cortex

Question 25

Scotoma

Answer 25

Blindness

Question 26

On-Center Bipolar Cells

Answer 26

Turning a light on in the center of an on-center cell excites the cell because it receives less glutamate which otherwise inhibits on-center bipolar cells

Question 27

Off-Center Bipolar Cells

Answer 27

Turning off light in the center of an off-center bipolar cell's receptive field excites the cell because it receives more glutamate which depolarizes off-center bipolar cells

Question 28

Bipolar cells also release...

Answer 28

Glutamate. Therefore, when a light is turned on, on-center bipolar cells depolarize on-center ganglion cells and when a light is turned off, off-center bipolar cells depolarize (excite) off-center ganglion cells

Question 29

On-center/Off-surround

Answer 29

Referring to a concentric receptive field in which the center excites the cell of interest while the surround inhibits it

Question 30

Off-center/On-surround

Answer 30

Referring to a concentric receptive field in which the center inhibits the cell of interest while the surround excites it

Question 31

Parvocellular vs Magnocellular

Answer 31

Small vs. Big

Question 32

Hubel and Wiesel

Answer 32

Reported that visual cortical cells require more specific elongated stimuli than those that activate LGN cells.

Question 33

Simple Cortical Cells

Answer 33

A cell in the visual cortex that responds best to an edge or a bar that has a particular width, orientation and location

Question 34

Complex Cortical Cells

Answer 34

A cell in the visual cortex that responds best to a bar of a particular size and orientation anywhere within a particular area of the visual field

Question 35

Trichromatic Hypothesis

Answer 35

There are three different types of cones, each excited by a different region of the spectrum and each having a separate pathway to the brain

Question 36

Opponent-Process Hypothesis

Answer 36

The theory that color vision depends on systems that produce opposite responses to light of different wavelengths

Question 37

Hemoltz

Answer 37

Trichromatic Hypothesis

Question 38

Hering

Answer 38

Opponent-Process Hypothesis