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The Endowment for Human Development
The Endowment for Human Development
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Implantation Well Underway

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.
Hatched Blastocyst
Hatched Blastocyst
Free Blastocyst  (without zona)
Free Blastocyst (without zona)
Implantation Well Underway
Implantation Well Underway
Embryo Cross Section 8-9 Days
Embryo Cross Section 8-9 Days
Embryo at About 11 Days
Embryo at About 11 Days
Tube Shaped Heart
Tube Shaped Heart
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