Fourth Week Flashcards
during the fourth week or prenatal development, within the embryonic period, the disc undergoes______?
embryonic folding
the embryonic folding will cause the endoderm cell layer to become _____ tissue and the ectoderm the most ______ tissue
endoderm cell layer becomes the deepest tissue and the ectoderm cell layer becomes the most superficial tissue
describe the embryonic folding
the trilaminar disc is now tubular in shape
what is the orientation of tissues of the embryonic folding?
has 2 membranes; has only 2 tissue layers
what are the membranes?
- buccopharyngeal membrane
2. cloacal membrane
what will the buccopharyngeal membrane become?
it will become the primitive mouth
what will the cloacal membrane become?
it will become the anus
the buccopharyngeal is at what end?
will be at the cephalic end
what is also developing during the fourth week?
the neural tube development is also developing
what does the neural tube form?
it forms our spine
the neural tube has what sides?
the anterior end and the posterior end
what does the anterior end give rise to?
gives rise to the brain
what does the posterior end five rise to?
gives rise to the spinal cord
what are the neural tube defects that could happen in the posterior end?
spina-bifida (can survive)
.7 per 1,000 births
what are the neural tube defects that could happen in the anterior end?
anencephaly
1 in 10,000 births
