exam 2 Flashcards
neurosurgery
t or f the retina cannot act as an organizer
false
eye is a neural tube. an outgrowth of the _____ (region of brain)
diencephalon
cilia and flagella can only be on the ______ surface of the epithelial cell
APICAL
sensory cells must have their apical surface facing toward or away from the fluid environment that the sensation moves through?
TOWARD
fluid is gone from what structure in the MATURE eye
optic vesicle
organize chronologically:
Retina, optic vesicle, optic cup
lens pit, lens placode, lens, lens vesicle
optic vesicle > optic cup > retina
lens placode > lens pit > lens vesicle > lens
retinal cell division takes place on the _____ side of the _____ layer and daughter cells that leave delaminate by penetrating _________
retinal cell division takes place on the APICAL side of the EPITHELIAL layer and daughter cells that leave delaminate by penetrating the BASAL LAMINA
individual cell clones are shown to extend linearly in the retina. Does this finding show that the cells are migrating VERTICALLY or HORIZONTALLY
Vertically, like in the cortex. from apical layer to granule cell layer
t or f. when following a progenitor cell on its clonal migration pathway in the retina, you should expect to see one cell type all the way through
false. vertical migration of progenitor clones results in multiple cell types (photoreceptors, neurons, glia), showing that these retinal progenitors are multipotent
in retina, expect what cell type to appear first, and what type to appear last? RPC, Ganglion, Muller glia
first= RPC and ganglion last= muller glia
a retinal progenitor cell that is NOT exposed to Neurogenin 2 cannot differentiate into _____. A retinal progenitor cell that is exposed to neurogenin 2 can differentiate into ______
NO neurogenin2 = NO retinal ganglion cells. bHLH TF
(but can differentiate into all other retinal cell types)
Yes neurogenin2= differentiation into ALL retinal cell types including Retinal ganglion cells
in retina, is neurogenin2 seen to be present early or late in development? explain
EARLY. Neurogenin 2 allows for differentiation of RPCs to retinal ganglion cells, the first cell group to usually show up in differentiation.
a retinal progenitor cell that is exposed to more neurod1 and math3 than math5 is directed toward what cell fate? how about vice versa?
\+++neurod1/math3 = amacrine cell \+++math5 = Retinal ganglion cell
what protein concentration remains constant during retinal development and is indicative of formation of late-born types?
[Casz1] remains constant throughout retinal development but is inhibited in early developmental stages by Ikaros. since there is less ikaros later on, there is more ACTIVE casz1, causing more late-born types
[casz1] remains constant throughout retinal development, but is inhibited in early developmental stages by ____
Ikaros. A KO of ikaros yields very few early-born types.
the presence of an miRNA that silences Ikaros would result in _____ (retinal development)
low amount of early born type cells, large amount of late born type cells due to increased activation of Casz1
t or f retinal cell fate is entirely stochastic
false, it is stochastic but the probability of a particular fate is the same as the proportion of that cell type in the mature retina. Weighted die
avian high acuity area (HAA) is specified by high concentrations of what and low concentrations of what
+++[cyp26] +++[FGF8] —[RA]. This area is devoid of rods and packed with cones. If retinoic acid is added to this area with an inhibitor of RA degradation, rods will be present in this area. This is just an example of the fact that there may be inherent biases in the strength of certain repressors over others
intracellular signalling for axon guidance particularly targets _____-based motility.
actin-based motility.
ECM molecules signal for changes in direction (attraction and repulsion) via various _____
integrins
cell-cell contact for axonal guidance- CAMS and cadherins are usually (positive or negative) signals for growth cone motility
positive (permissive)
cell-cell contact for axonal guidance- semaphorins and ephrins are usually (positive or negative) signals for growth cone motility
negative. Repulsive signals that cause the growth cone to stop. Doesn’t allow axon to grow past its correct target
t or f ephrins and eph receptors are an example of bidirectional signalling because binding of the two can cause cleavage of both
true
netrin-DCC signaling (attracts or repels) growth cones
attracts. diffusible signal