Lecture #3 Flashcards
what is the process called in which there is the generation of the neural tube soon after gastrulation?
neurulation
soon after the closure of the neural tube what subset of cells is generated?
neural crest cells → will go on to generate different different types of cells including sensory ganglia, parasympathetic and sympathetic outflows, myelin of the PNS and skull
what is the initial subdivision of the CNS?
brain and spinal cord
inside the brain at the beginning of development, there is the formation of three rudimentary vesicles, what are they?
prosencephalon (anterior), mesencephalon (intermediate), and rhombencephalon (posterior)
as development occurs, the three original vesicles turn into five - what are the new divisions?
prosencephalon: telencephalon → cerebral cortex and corpus striatum (from the basal region of the telencephalon)
diencephalon that connects tissues between the telencephalon and the subtelencephalic regions composed of the thalamus, hypothalamus, and epithalamus
what two divisions will come from the rhombencephalon?
metencephalon (forms the pons and cerebellum) and myelencephalon (medulla oblongata: part of the CNS connecting the brain with the spinal cord)
what is the most important concept of the brain differentiation during development?
dramatic elongation and tangential expansion of the two tele cephalic vesicles, that will general the two cerebral hemispheres
the telencephalon vesicles connect to the diencephalon, and are composed of two half - what are they?
dorsal half: pallium
ventral half: striatum
why is the striatum important?
its a sort of tissue that can modulate the firing and functional activity of the telencephalic vesicles → receives a huge amount of information from telencephalon vesicles and modulates this information
describe the crossroads in the striatum:
allows the cortex to send messages to the spinal cord and vice cress so the cortex can receive information from the periphery
what are the two early developmental regions of the striatum?
medial and lateral ganglia eminences
what are the two subdivisions of the cortex of the early striatum?
piriform cortex: specific part of the telencephalon vesicle that manages olfactory impulse
hippocampus
what is another term used to refer to the two subdivisions of the cortex?
allocortex
in mammals, how many layers make up the neocortex?
6
what four structures help to protect the embryo?
- placenta (filter)
- amniotic cavity
- yolk sac
- allantoid (important for gas exchange between the embryo and the placenta)
what is an example of a virus that can cross the placenta and affect the embryo?
Rubella
which mosquito is a carrier able to transmit Zika virus?
aedes aegypti
what are the main symptoms of Zika?
myalgia, maculopapular rash, arthralgia, and sometimes cardiovascular abnormalities
some patients starting from the micropolynesia outbreak we also have Guillian-Barré syndrome
what is Guillian-Barré syndrome?
a rare and sever disease that occurs after an acute infectious procedure affecting the PNS
if we have an inflammatory neuropathy in the PNS we start to lose tendon reflex and have severe weakness, and in severe cases also failure of the respiratory muscles
what is the current therapeutic strategy for Guillian-Barré syndrome?
aphaeresis of immunoglobulin or the administration of specific immunoglobulin to block the pathologic activation of the immune system
what is the main etiology of Guillian-Barré syndrome?
campylobacter jejuni: activation of the immune system and for the mimicry, the immune system starts to attack the myelin of the PNS causing this tremendous disorder
what are the three lineages of Zika?
- Asian / American: Brazil, Columbia, Guatemala - associated with severe microencephaly
- African lineage I: not associated with microencephaly or Guillian-Barré syndrome
- African lineage II: well investigated
what did scientists find when they did an experiment on a fetus with Zika in 2016?
calcification over the white matter of the brain, severe hypo development of the cerebral cortex, and an increased size of the ventricular cavity
what specific morphological differences did they find in the brain of the fetus?
very few sulci and gyri - the brain was very smooth and the neuroepithelial cells did not tangentially expand
also an accumulation of immune cells in the brain indicating an inflammatory reaction
what were some models used to study Zika?
- iPSCs derived from human neuroepithelial cells → proved the Zika can affect neuroepithelial cells
- spheres
mice → similar brain development and large potential for genetic manipulation - organoids
what specific protein is normally located in cells near the mitotic spindle that is important for the organization of the spindle and therefore for symmetric cell division?
TBK1
what happens to the TBK1 protein in the case of Zika virus?
TBK1 translocates from the spindle region to the mitochondria because it is also involved with the antiviral response
When TBK1 is in the mitochondria it can’t work in the spindle and this causes aberrant formation of the mitotic spindle leading to an altered cell division that causes the apoptosis of cells