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The Endowment for Human Development
The Endowment for Human Development
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Slideshow: Slideshow 1

Implantation Well Underway

#20, Slide 5 of 19

8 days

From The Biology of Prenatal Development.Buy Now

Label Key:

1. trophoblast cells
2. inner cell mass
3. decidual reaction (site of early placenta formation)
4. inner lining of uterine wall (endometrium), seen in cross-section
5. muscle layer of uterine wall (myometrium)
6. uterine cavity
All ages referenced to fertilization, not last menstrual period.
Fertilization BeginsThree-Cell EmbryoEarly BlastocystImplantation Well UnderwayThe 4-Week EmbryoVitelline Vessels and Yolk SacHand Plate and Vital OrgansHand, 7 Weeks Pregnant7½-Week EmbryoRight Eye and Facial Profile9-Week Fetus, MRI AnimationExit Stage LeftPosterior Surface of Left ThighStill HidingThe MouthFace, 27-Week FetusFace and Left ForearmReady for Birth and Beyond
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