Prenatal

la biología del
presents

THE ENDOWMENT FOR
HUMAN DEVELOPMENT

Desarrollo
Prenatal

24 mm
.94 in.

Writing and Research:
Brian J. Stillwell, M.D.

This program is distributed by
National Geographic Domestic
Home Entertainment. To purchase, call 1.800.627.5162 or
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Copyright © 2006 The Endowment for Human Development, Inc. All rights reserved.Principal Technical Advisor:
Mark T. Cullen, M.D.

Technical Review:
James H. Baker, Ph.D.
Enid Gilbert-Barness, M.D.
David H. Bernanke, Ph.D.
Mark J. Holterman, M.D., Ph.D.
David L. Bolender, Ph.D.
Paul A. Krieg, Ph.D.
Professor Stuart Campbell, D.Sc.
Maria Michejda, M.D.
Bruce M. Carlson, M.D., Ph.D.
Maurice J. Pescitelli Jr., Ph.D.

Julian E. De Lia, M.D., M.B.A.Charles L. Saxe, III, Ph.D.
Charles H. Ellis Jr., Ph.D.
Mark F. Seifert, Ph.D.
Ona Marie Faye-Petersen, M.D.
Allan R. Sinning, Ph.D.
David W. Fontaine, M.D.
Bradley R. Smith, Ph.D.
Raymond F. Gasser, Ph.D.
Sam R. Voora, M.D.

www.ehd.org

Table of Contents
Chapter 1 – Introduction................................................................................................................................2
Chapter 2 – Terminology ...............................................................................................................................2
THE EMBRYONIC PERIOD (THE FIRST 8 WEEKS) ..................................................................................2
EMBRYONIC DEVELOPMENT: THE FIRST 4 WEEKS..........................................................................................2
Chapter 3 – Fertilization ................................................................................................................................2
Chapter 4 – DNA, Cell Division, and Early Pregnancy Factor (EPF) ............................................................3
Chapter 5 – Early Stages (Morula and Blastocyst) andStem Cells..............................................................4
Chapter 6 – 1 to 1 1/2 Weeks: Implantation and Human Chorionic Gonadotropin (hCG) ............................4
Chapter 7 – The Placenta and Umbilical Cord ..............................................................................................4
Chapter 8 – Nutrition and Protection.............................................................................................................5
Chapter 9 – 2 to 4 Weeks: Germ Layers and Organ Formation ...................................................................5
Chapter 10 – 3 to 4 Weeks: The Folding of the Embryo ...............................................................................6
EMBRYONIC DEVELOPMENT: 4 TO 6 WEEKS...................................................................................................6
Chapter 11 – 4 Weeks: Amniotic Fluid ..........................................................................................................6
Chapter 12 – The Heart in Action..................................................................................................................6Chapter 13 – Brain Growth............................................................................................................................6
Chapter 14 – Limb Buds................................................................................................................................6
Chapter 15 – 5 Weeks: CerebralHemispheres.............................................................................................7
Chapter 16 – Major Airways ..........................................................................................................................7
Chapter 17 – Liver and Kidneys ....................................................................................................................7
Chapter 18 – Yolk Sac and Germ Cells...