06 Visual System Intro & Evolution

Question 1

The center of the fovea is made up of only ____ and has approximately how many?

Answer 1

Cones; 30

Question 2

About how many cones does one diffuse bipolar cell receive signals from, and how many diffuse bipolar cells communicate to one ganglion cell?

Answer 2

10 cones to 1 diffuse bipolar cell

5 - 6 diffuse bipolar cells to 1 ganglion cell

Question 3

After leaving the ganglion cell through the axon, light signals pass through which 3 structures before arriving to the cortex? Name them in order through which the signals would travel.

Answer 3

Optic nerve, optic chiasm, optic tract

Question 4

The fiber bundles from the thalamus leading to the occipital lobe are also known as ______.

Answer 4

Meyer’s Loop

Question 5

The number of ganglion cells is proportional to the number of ______ in a specific area of the retina.

Answer 5

Photoreceptors

Question 6

The area centralis (central part of the fovea) is included in which cortical region?

Answer 6

V1

Question 7

The 3 components of the Natural Selection Algorithm are:

Answer 7

selection, variation, heredity

Question 8

If all 3 components of the Natural Selection Algorithms holds true, then you MUST get:

Answer 8

design out of chaos w/o the aid of Mind

Question 9

______ is when the population reproduces at less than the replacement rate

Answer 9

extinction

Question 10

According to Malthus, ‘stable’ means:

Answer 10

overproduction at a rate that balances at the death rate of offspring

Question 11

Malthus looked at variation through _________ while Darwin looked at it through ________

Answer 11

social factors, biological factors

Question 12

Put the 4 phrases in order based on the definition of ‘heredity’:

• new species produced overtime
• advantage to individuals w/ variation
• selection pressures
• variations passed on to next generation

Answer 12

selection pressure => advantage to individuals w/ variation => variations passed on to next generation => new species produced overtime

Question 13

Meme:

Answer 13

that which is imitated

Question 14

T or F: According to meme theory, humans are gene machines AND meme machines while others are only gene machines

Answer 14

True

Question 15

____ out of 30 phyla’s have eyes that forms images which make up ____% of the species

Answer 15

6, 95

Question 16

social factors are:

Answer 16

power, privilege, injustice, and class warfare

Question 17

Why do signals from the central part of the fovea correspond to such a larger area of the cortex?

Answer 17

The larger area of cortex is proportional to the large amount of signals coming from the fovea which is most densely packed with cells.

Question 18

T or F: The 3 cortical regions are adjacent to each other thus allowing signals to be passed from V3 to V2 and then V1.

Answer 18

False; signals are passed from V1 to V2 to V3

Question 19

What differentiates the areas of the visual cortical maps?

Answer 19

The areas of retina that the signals are coming from.

Question 20

The _____ is the most densely packed part of the retina.

Answer 20

Fovea

Question 21

Retina circulation is ____ more demanding than the brain.

Answer 21

7X

Question 22

Vascularization is all over the retina except?

Answer 22

Fovea

Question 23

What type of junctions are present in the retinal layer and what is its function?

Answer 23

Tight gap junctions are present and they allow oxygen to get through and protect retina cells from harmful proteins.

Question 24

Which 2 structures are coupled together in the course of development?

Answer 24

The retina and lens

Question 25

Explain the difference between a spot and a streak and which type of visual space do humans have?

Answer 25

Spot - an area centralis receiving from a small circular region in the visual space Streak - a visual streak receives from an elongated horizontal region in visual space. Humans have developed a spot visual space.

Question 26

List the 5 classes of cells in the retina.

Answer 26

Photoreceptors, horizontal cells, bipolar cells, amacrine cells, ganglion cells

Question 27

Amacrine cells modulate connection between which of the 2 cells present in the retina?

Answer 27

Bipolar and ganglion cells

Question 28

The biggest structural difference between the rods and cones are in the way the ____ is formed.

Answer 28

Axon

Question 29

In which segment of the rods/cones does photogenesis occur?

Answer 29

Outer segment

Question 30

``` Out of the variety of eyes, which best represents the human eye? A. pinhole B. eye spot C. camera lens D. streak ```

Answer 30

C. camera lens

Question 31

``` Which protein molecule catches light in most species? A. Rhodopsin B. S-opsin C. M-opsin D. L-opsin ```

Answer 31

A. Rhodopsin

Question 32

Studies show that eye making genes like Pax-6 could be transferred to fruit flies and produce functional eyes in odd places. True or False

Answer 32

False

Question 33

Species that do not have eyes still possess eye making genes. True or False

Answer 33

True

Question 34

``` It takes a number of generations to evolve a more complex optical geometry of vertebrate such as _______. A. pinhole B. camera eye with refracting lens C. streak D. spot ```

Answer 34

B. camera eye with refracting lens

Question 35

After stage 5 of development, the crystallized lens is developed to help focalize after how many steps? A. 192 B. 308 C. 296

Answer 35

A. 192

Question 36

There are 1829 steps of 1% change needed for entire developmental sequence of the eyes. True or False

Answer 36

True

Question 37

In a myopic patient __________. A. the eye will elongate to improve clarity B. the eye will shorten to improve clarity C. orbital system adapts to environment to help improve clarity of vision D. both A and C

Answer 37

D. both A and C

Question 38

Eye making genes have multiple purposes besides being involved in ocular development such as the other sensory systems like the nose. True or False

Answer 38

True