Development of Visual Pathway Flashcards
(20 cards)
At what week does the visual system begin to develop?
3 weeks
What embryological tissue gives rise to the retina, the fibers of the optic nerve and smooth muscle of the iris?
Neuroectoderm
What embrylogical tissue forms the corneal and conj. epithelium, the lens and the lacrimal and tarsal glands?
Surface ectoderm
What embryological tissue forms the corneal stroma, sclera, choroid, iris, ciliary muscle, vitreous body and the cells lining the anterior chamber?
Mesenchyme
What part of the brain does the eye develop from?
Forebrain (specifically diencephalon)
Around what embryo day does the retina begin to develop?
30 days
Around what embryo day does the LGN begin to develop?
36 days
Around what embryo day does the cortex begin to develop?
40 days
People who become blind early tend to have a thicker visual cortex due to the failure of what?
Failure of pruning and retraction of processes
Initial steps of cell generation are under what 2 types of control?
Chemical or molecular control
Once synaptic connections are made between the cells, development is more influenced by what?
Electrical activity between the cells in the system
What retinal cells develop first?
- Ganglion
- Horizontal
- Amacrine cells
- Cone cells
What retinal cells develop second?
- Rods
- Bipolar cells
- Mueller glial cels
T/F: The central part of the retina is generated first and the peripheral parts later.
True
What guids the axons of ganglion cells to the optic nerve head?
Proteins
If an animal is kept in the dark, will the segregation of on-off responses of ganglion cells develop?
No
If the electrical responses are blocked, will the segregation of on-off responses of ganglion cells develop?
No
What guides the nasal retina nerve fiber axons into, through and out of the chiasm ?
Slits - extracellular matrix molecules
What affects the guidance facts expressed by retinal ganglin cells in Albinos?
the lack of melanin in the pigment epithelium in the retina
In albinos, some of the temporal half of the retina project abnormally tot he contralateral LGN. What does this cause in the patient?
Lack of binocular coordination between the 2 images/eyes
