What does organogenesis start with
Starts with a tube
what is nueralation
formation of nueral tube
what is somitogenesis
the segmentation of mesodermal cells in developing trunk, forms the axial skeletal and mucles.
where do the brain structures form
form at the anterior end of nueral tube
where tdoes the formation of heart start and tube gut
Tube gut forms via folding of the tube and the heart starts forming from the tube as well.
what is Nueralation
IT is the development of nervous systems from nueroectodermal cells.
What is notochord
it is mesodermaly driven and signals the overlying ectoderm in dorsal midline to thiken and form nueral plate.
what does the nueral plate do
they disconect from the nueral tube b/c the edges of the plate fold into themeselves and release nueral cells.
How do the nueral plate fold
by cytoskeletal changes in cells.
what are nueral crest
released by the disconnection of the nueral tube, considered the 4th germ layer, migrate all over to form many important structures.
from what do the brain and spinal cord form from
develop from nueral tube
what are the steps in nueralation
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what do the dificiency fo maternal folate cause in the first few weeks of pregnancy
causes nueral tube defects
spina bifida - failure of posterior nueropore closure
anencephaly - failure of anterior nueropore closure
what do the nueral crests do?
they are the left over cells from nueralation they are migratory, contribute to periferal nervous system,septum that partitions the outflow tracts of heart into two major vessels that separate systemic and pulmonary circulation
what are somites
they are temporary segment structures on either side of the nueral tube, they are made from mesoderms that are split, and they grive rise to verteral column, muscles of ribs, limds and dermis of skin.
what is embryonic folding
folding from flat disc to 3-d cylinder by end of week 4. Tube-within Tube body plan. expansion, folding and fusion of embro. inner ture is future gastrointestinal tract.
what is the first fully functional system to develop
the circulatory system
when does the heart start beating
4 weeks
how is the heart formed
cranial mesoderm cells condence into paired tubes that fuse to form single heart tube, connected by capillaries to chornionic villi then the rudimentary tube loops upon itself
where are the RBCs first produced in and where will they be produced from in the future
produced in the liver and will be later produced by bone marrow
what do the partitions form in the heart
form 4 rudimentary chambers
what happens to embryo at 7 weeks
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