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level: Level 1 of 5. Derivatives of 3 germinal layers

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level questions: Level 1 of 5. Derivatives of 3 germinal layers

Question	Answer
formation of the three primary germ layers occurs during the first two weeks of development.	Gastrulation
it takes place after cleavage and the formation of the blastula and the primitive streak.	Gastrulation
forms as a depression in the centre of the primitive node which connects to the notochord which lies directly underneath.	primitive pit
what are the 3 germ layer?	ectoderm, mesoderm, and endoderm
The germ layers form during the process of	gastrulation
lies between the endoderm and the ectoderm	mesoderm
The fertilized egg initially undergoes a rapid divisions that leads to the formation of a ball of cells called	morula
fluids accumulates in the morula, and its cells realign themselves to form a fluid hallow ball, called:	blastocyst
what are the 2 cell populations that can be distinguished within the blastocyst?	trophoblast and embryoblast
lining the cavity (the primitive yolk sac) called?	trophoblast cells
In blastocyst there is a small cluster within the cavity, called the inner mass or the?	embyoblast
it forms the embryo	embryoblast
it is associated with the implantation of embryo and formation of placenta	trophoblast cells
how many days does the cell of embryoblast differentiate into two layered disk?	8 days
what do you call the two layered disk found in blastula stage?	bilaminar embryonic disk
in this layer the cells are situated dorsally and are columnar and reorganize to form the amniotic cavity	ectodermal layer
In this layer cells on the ventral aspect and are cuboidal and form the roof of a second cavity (secondary yolk sac)	endodermal layer
During the time the axis of the embryo is established and is represented by a slight enlargement of the ectodermal and endodermal cells at the head (cephalic or rostral) end of the embryo in a region known as the _________ where ectoderm and endoderm are in contact.	prochordal (or prechordal) plate
form the floor of amniotic cavity	ectoderm
the floor of the amniotic cavity is formed by ectoderm, and within it a structure called the ________ develops along the midline by cellular convergence.	primitive streak
the rostral end of the streak finishes in a small depression called the __________.	primitive node or pit
cells of the _________ layer migrate through streak and between the ectoderm and endoderm.	ectodermal
three stages of prenatal development	germinal, embryonic, and fetal stage
depicts the floor of the amniotic cavity, formed by _________ ______ of the bilaminar embryo.	ectodermal layer
this cells converge toward the midline to form the primitive streak	ectodermal cells
in a primitive streak a narrow groove terminating in a circular depression called:	primitive node