Anatomy chapter 3

exam one material

What are the three developmental stages of the prenatal period

Pre-embryonic period

embryonic period

fetal period

Pre-embryonic period

first 2 weeks after fertilization

formation of blastocyst

ends with implantation in lining of uterus

Embryonic period

3rd- 8 weeks

all major organ systems begin to develop

tissues develop

Fetal period

9th-38 weeks

growth & development continues

period ends at birth

What happens after zygote forms

it undergoes a series of mitotic divisions called cleavage

what is the 16-cell stage called?

morula

What comes after morula

after the morula enters the uterine cavity it becomes a blastocyst

Trophoblast

Outer ring of cells that develop into the chorion

Embryoblast

cluster of tightly packed cells inside one side of the blastocyst that will form the embryo

Hypoblast

layer of small cuboidal cells facing the blastocyst cavity

Epiblast

layer of columnar cells deep to the hypoblast

What happens at day 8

The cells of the embryoblast differentiate into hypoblast and epiblast

What forms the bilaminar germinal disc

The hypoblast and eppiblast

Amnion

thin layer of cells that forms above and is derived from the epiblast

amniotic cavity

fluid filled found between the amnion and epiblast layer

Yolk sac

serves as a site for early blood cell and vessel formation

What 3 structures do the germinal disc and trophoblast produce?

Yolk sac, amnion, chorion

Chorion

outermost membrane responsible for formation of the placenta

Gastrulation

process by which cells from the epiblast migrate to form the primary germ layers