Germ Layers, Gastrulation, & Neurulation Flashcards
What is the role of the primitive streak in gastrulation?
Cells migrate to and then from the primitive stream with signals for differentiation. At first, cells are directed to become future endoderm. Later, cells are directed to become mesoderm.
What is the primitive node?
The primitive node is located caudally to the primitive steak and is the most caudal aspect of the future body’s axis.
The CNS, epidermis, and neural crest cells are all derived from what germ layer?
Ectoderm
The lining of the GI tract, digestive viscera, and sex cells are derived from what germ layer?
Endoderm
The mesoderm forms what develops into what?
Musculoskeletal system (somatic/voluntary and splanchnic/involuntary)
Describe the formation of the notochord.
The notochord begins as a specialized mesoderm near the primitive node. Cells grow and extend towards the prechordal plate, which is near the future mouth of the embryo.
What is the role of the notochord in neural tube differentiation?
The notochord signals the ectoderm to fold in upon itself. Cells nearest the neural groove ultimately form the neural tube. Cells near the neural crest later form spinal ganglion. Cells further out from the neural groove form epidermis.
Insults during which period are most likely to cause abortion of the embryo?
The first two weeks, pre-neurlation
Insults during weeks 2-8 of pregnancy are most likely to cause what?
Major structural abnormalities
What are remnants of embryonic cells that form midline tumors close to the vertebral column?
Teratomas
What causes a sacrococcygeal teratoma?
Sacrococcygeal teratomas are tumors containing tissues derived from all three germ layers in incomplete stages of differentiation. They are derived from pluripotent primitive streak cells. The mechanism of such teratomas is unknown.
Flip card to see differentiation of germ layers.
