Embryo: Trilaminar Embryo - 3rd Week Flashcards
0
Q
What is the primitive streak?
A
A groove on the surface of the caudal end of the epiblast at about day 16
1
Q
What happens during Gastrulation?
A
- Formation of 3 germ layers: the ectoderm, mesoderm, and endoderm
- Cranial-caudal (longitudinal) axis; bilateral symmetry
2
Q
What is the buccopharyngeal membrane?
A
Thickened hypoblast at cephalic region
3
Q
What tissue does the buccopharyngeal membrane lack?
A
Mesoderm
4
Q
The cloacal membrane end becomes what?
A
Anus
5
Q
What is the depression on the node referred to as?
A
Primitive pit
6
Q
The notochord process (hollow tube) becomes what?
A
Notochordal plate then notochord
7
Q
What tissues form the notochord?
A
Mesoderm
8
Q
What is the notochord?
A
- Forms in cranial to caudal direction
- basis for axial skeleton
- induces neural plate formation in ectoderm - CNS
- powerful inducer of surrounding structures in mesoderm and endoderm
9
Q
Where is the notochord located?
A
Midline from the primitive pit to the buccopharyngeal membrane in the mesodermal layer
