Folding of the Embryo Flashcards
What are the two parts of longitudinal (median plane) embryo folding?
Generally how do they occur?
- Head Fold
- the neural fold grows cranially over the OP membrane + heart
- septum transversum, heart, pericardium + OP move ventrally
- yolk sac folds in to become foregut
- Tail Fold
- distal neural tube + caudal eminence grow over cloacal membrane
- endodermal layer folds in to form hindgut
- connecting stalk becomes ventral w/ allantois incorporated into the embryo
What is the raised part of the neural tube at the cranial end of the folding embryo called?
What does it become?
neural fold
becomes forebrain … then brain
What is the area between the pericardial coelom and the yolk sac?
septum transversum
What is the cavity near the heart called?
pericardial coelom
What forms cranially when the yolk sac folds in?
foregut
What is the area in the amnion just ventral to the OP membrane in the folded embryo?
It becomes?
Stomodeum
becomes mouth and anterior pituitary
What is the name of the caudal structure which grows outward and folds downward in the fail fold?
What does it project over?
**caudal eminence **
projects over cloacal membrane
What forms when part of the endodermal layer folds in during the tail fold?
What does it become?
hindgut
becomes descending colon
What forms from the terminal hindgut?
How?
cloaca
forms when terminal hindgut dilates
What is the name of the stalk connecting the midgut to the yolk sac, formed by the pinching action of embryonic folding?
**vitelline **or omphaloenteric duct
What produces the horizontal plane fold?
AKA lateral folding
produced by rapid growth of the spinal cord and somites
What is the name of the area that forms when part of the endoderm layer incorporates into the embryo during horizontal plane folding?
midgut
What does lateral embryo folding look like?
How does the head fold area look?
