name the three germ layers in an early stage embryo
ectoderm-skin and ns mesoderm-muscle and bone endoderm-lining of organs
how does the ectoderm give rise to the CNS and PNS
The ectoderm become thickened at week three and the sides start to rise (nueral fold) which makes a dent called the nueral groove. They come together to form the nueral tube.(week 4) The cells that stay in make up the CNS and the cells that migrate out make up nueral crest-PNS
undergoes three stages of development: transformation into the neural plate, transformation into the neural groove (with associated neural folds), and transformation into the neural tube.
____ are mesoderm that will give rise to bones of the skeleton and muscles.
failure to close the rostral (anterior) nueropore leads to ...
failure to close the posterior (caudal) nueropore leads to...
what are the parts of the nueral groove during nueral tube formation?
medial hinge point, lateral hinge point
name the brain flexures and vessicles in a four week embryo
hindbrain (rhomencephalon) midbrain (mesensephalon) and forebrain (prosencephalon) the flexures are cervical and cephalic
what are the vessicles and flexures in a six week embryo