Wk10-12 VIGNETTES

Question 1

Explain Neurulation

Answer 1

Signals converge on the middle region of the ectoderm and induce it to become neural tissue.

neural folds starting to join up first in the middle and then zippering down and up

The tube itself separated from top layer of ectoderm, becomes epidermis encapsulating the brain.

Question 2

Axogenesis

Answer 2

axon regrowth from pre-existing, injured neurons through the injury site to re-establish connections

Question 3

Optic nerve axogenesis

Answer 3

optic nerve is severed, the retinal ganglion cells can undergo apoptosis blocking regeneration if the cell bodies die off.

When the nerve gets re-established sometimes it synapses on the wrong target cell in the LGN, causing weaker strength and loss of visual signal.

Question 4

Rewiring

Answer 4

new connections are formed to replace ones that are damaged to re-establish function of the neural pathway

Question 5

Ferret rewiring

Answer 5

If you damage the visual cortex by a lesion in the LGN, in the ferret brain it can rewire using the MGN instead making the auditory cortex able to process visual information instead of auditory.

Question 6

Neurogenesis

Answer 6

the production of new neuronal cells from neuroepithelial cells

to radial glial cells, to B cells to neurons and oligodendrocytes

hippocampus most active for learning and memory

Question 7

Dedifferentiation

Answer 7

can be used to induce them to return back to a more immature phenotype

Question 8

Transdifferentiation

Answer 8

can be used to induce them into a different cell, usually closely related.

Question 9

Reprogramming

Answer 9

can be used to harvest new cells by exposing old cells to factors making them stem cells.

Question 10

Sources of pluripotent stem cells

Answer 10

naturally occurring pluripotent stem cells from the embryonic stem cells in the blastocyst

embryonic germ cells from primordial germ cells

germ line derived pluripotent stem cells from spermatogonical stem cells of neonatal and adult testis.

Question 11

fuse somatic cell with embryonic cell…

Answer 11

Nuclear transfer ES cells by implanting nucleus from somatic cells into embryonic stem cell

Induced pluripotent stem cells by exposing to different transcription factors

Question 12

Why is parkinson’s disease a good candidate for stem cell therapy

Answer 12

we know select population of neurons affected

easy to harvest dopaminergic neurons