06 Visual System Intro & Evolution Flashcards
The center of the fovea is made up of only ____ and has approximately how many?
Cones; 30
About how many cones does one diffuse bipolar cell receive signals from, and how many diffuse bipolar cells communicate to one ganglion cell?
10 cones to 1 diffuse bipolar cell
5 - 6 diffuse bipolar cells to 1 ganglion cell
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.
Optic nerve, optic chiasm, optic tract
The fiber bundles from the thalamus leading to the occipital lobe are also known as ______.
Meyer’s Loop
The number of ganglion cells is proportional to the number of ______ in a specific area of the retina.
Photoreceptors
The area centralis (central part of the fovea) is included in which cortical region?
V1
The 3 components of the Natural Selection Algorithm are:
selection, variation, heredity
If all 3 components of the Natural Selection Algorithms holds true, then you MUST get:
design out of chaos w/o the aid of Mind
______ is when the population reproduces at less than the replacement rate
extinction
According to Malthus, ‘stable’ means:
overproduction at a rate that balances at the death rate of offspring
Malthus looked at variation through _________ while Darwin looked at it through ________
social factors, biological factors
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
selection pressure => advantage to individuals w/ variation => variations passed on to next generation => new species produced overtime
Meme:
that which is imitated
T or F: According to meme theory, humans are gene machines AND meme machines while others are only gene machines
True
____ out of 30 phyla’s have eyes that forms images which make up ____% of the species
6, 95
social factors are:
power, privilege, injustice, and class warfare
Why do signals from the central part of the fovea correspond to such a larger area of the cortex?
The larger area of cortex is proportional to the large amount of signals coming from the fovea which is most densely packed with cells.
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.
False; signals are passed from V1 to V2 to V3
What differentiates the areas of the visual cortical maps?
The areas of retina that the signals are coming from.
The _____ is the most densely packed part of the retina.
Fovea
Retina circulation is ____ more demanding than the brain.
7X
Vascularization is all over the retina except?
Fovea
What type of junctions are present in the retinal layer and what is its function?
Tight gap junctions are present and they allow oxygen to get through and protect retina cells from harmful proteins.
Which 2 structures are coupled together in the course of development?
The retina and lens
Explain the difference between a spot and a streak and which type of visual space do humans have?
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.
List the 5 classes of cells in the retina.
Photoreceptors, horizontal cells, bipolar cells, amacrine cells, ganglion cells
Amacrine cells modulate connection between which of the 2 cells present in the retina?
Bipolar and ganglion cells
The biggest structural difference between the rods and cones are in the way the ____ is formed.
Axon
In which segment of the rods/cones does photogenesis occur?
Outer segment
Out of the variety of eyes, which best represents the human eye? A. pinhole B. eye spot C. camera lens D. streak
C. camera lens
Which protein molecule catches light in most species? A. Rhodopsin B. S-opsin C. M-opsin D. L-opsin
A. Rhodopsin
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
False
Species that do not have eyes still possess eye making genes. True or False
True
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
B. camera eye with refracting lens
After stage 5 of development, the crystallized lens is developed to help focalize after how many steps?
A. 192
B. 308
C. 296
A. 192
There are 1829 steps of 1% change needed for entire developmental sequence of the eyes. True or False
True
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
D. both A and C
Eye making genes have multiple purposes besides being involved in ocular development such as the other sensory systems like the nose. True or False
True
