Gastrulation Flashcards
Which cell layer of the Bilaminar disc is ventral and which is dorsal?
Epiblast is dorsal
Hypoblast is ventral
When do syncytiotrophoblast and cytoptrophoblasts begin to undergo placentation?
In week 3
When does formation of the primitive streak begin?
Week 3
What is the primitive streak?
A slender midline structure with cellular enlargements surrounding it
What is the expansion of the primitive streak at the cranial end and what is the indentation called?
The primitive node and the primitive pit
When does development of the trilaminar disc begin?
Week 3
When does the future position of the cloacal membrane appear?
Week 3
What happens to cells in gastrulation?
Cells start to delaminate along the edge of the Bilaminar disc and move ventrally into the hypoblast layer. The new cell layer is the endoderm
What kind of cells fill the gap cause by gastrulation?
Mesodermal
What is ingression?
Movement and delimitation of cells between the endoderm and ectoderm
Where does the prechordal plate develop?
Along the primitive streak
What cranial structure do cells move towards from the primitive streak during ingression?
The oropharyngeal membrane
What is the function of the pre-chordal plate?
To act as an inducer to push the notochord up to the oropharyngeal membrane
What is the function of the neurenteric canal?
It allows communication between the amniotic cavity and yolk sac
What do the delaminated cells form during notochord formation?
A hollowed out tube
What happens to the tube formed by delaminate cells?
It starts to integrate with endoderm and flattens
What do source signalling molecules cause?
Vertebral column and neural tube formation
What is the function of the notochord?
To provide stability for developmental muscle attachment and to allow folding to occur around it
At what day is the notochordal process clear?
Day 17
What is the fate of the ectoderm?
Becomes epidermis, hair, nails, glands
Also nervous system
What are the 3 regions of the intraembryonic mesoderm?
Paraxial, intermediate and lateral plate mesoderm
What is the fate of paraxial mesoderm?
Axial skeleton (not cranium)
Majority skeletal muscle
Some of teh dermis of the central back
Somites
What are somites?
Balls of cells with mesenchymal interiors
What is the fate of intermediate mesoderm?
Urogenital system - kidneys, ureter, reproductive system
What is the fate of lateral plate mesoderm?
Somatic areas form majority of the dermis, lining body wall, bones upper and lower limbs
Visceral areas form cardiovascular system, mesothelial covering organs, smooth muscle
What is the fate of endoderm?
Lining gut tube, respiratory tract, bladder and urethra
