Neurulation and Somitogenesis Flashcards
s1 - What is neurulation?
Neurulation is the formation of the vertebrate nervous system in embryos.
s1 - What does the notochord do?
The notochord induces the formation of the CNS by signaling the ectoderm above it to form the neural plate.
s1 - What does the neural plate do?
The neural plate folds in on itself to form the neural tube, which later differentiates into the spinal cord and brain.
s1 - Where do neural crest cells come from and what do they do?
Neural crest cells are derived from the neural tube and migrate to form the PNS and other structures (melanocytes and cartilage of the head)
What forms the PNS?
the neural crest cells
From which tissue layer of the trilaminar disc does the notochord develop from?
the mesoderm layer
From which layer of the trilaminar disc does the neural tube develop?
the ectoderm layer
What is the neural plate composed of?
Neuroectoderm
On what day does the notochord begin to develop?
Day 19
How does the notochord develop?
Some mesoderm cells migrate cranially in the midline of the mesodermal layer to form a rod-like notochordal process.
In what way do the cells of the ectoderm change under the influence of the notochord?
the cells become thicker, more columnar, and narrower towards their apex, so the cells tilt towards each other and form the tube.
What does the neural plate border do?
Separates the ectoderm from the neural plate
What is the ectoderm layer called once the neural tube has been detached?
the epidermis
—-What do the pluripotent neural crest cells give rise to?—-
Spinal ganglia (dorsal root ganglia) Ganglia of the autonomic nervous system Ganglia of some cranial nerves Sheaths of peripheral nerves Meninges of brain and spinal cord Melanocytes Suprarenal medulla (adrenal gland) Skeletal and muscular components in the head
What day does the anterior/cranial neuropore close on?
Closes on day 24
What day does the posterior/caudal neuropore close on?
Day 26
What is the primordium of the CNS?
the neural plate
What does the notochord persist as in adults?
The nucleus pulposus in the intervertebral discs
where does the neural tube first close?
first closes at the level of the future C5
What are the three dilations of the cephalic neural tube, and what do they form in the adult brain?
prosencephalon - forebrain
mesencephalon - midbrain
rhombencephalon - hindbrain
