28
Pregnancy and Human
Development
From Egg to Zygote
(pp. 1065–1067)
Accomplishing Fertilization
(pp. 1065–1067)
Events of Embryonic Development:
Zygote to Blastocyst Implantation
(pp. 1067–1074)
Cleavage and Blastocyst Formation
(p. 1067)
Implantation (pp. 1067, 1070–1071)
Placentation (pp. 1071–1074)
Events of Embryonic Development:
Gastrula to Fetus
(pp. 1074–1081)
Formation and Roles of the Extraembryonic
Membranes (pp. 1074–1075)
Gastrulation: Germ Layer Formation
(pp. 1075–1076)
Organogenesis: Differentiation of the
Germ Layers (pp. 1076–1081)
Events of Fetal Development
(pp. 1081–1082)
Effects of Pregnancy on the Mother
(pp. 1082–1085)
Anatomical Changes (pp. 1082–1083)
Metabolic Changes (p. 1083)
Physiological Changes (pp. 1083–1085)
Parturition (Birth)
(pp. 1085–1087)
Initiation of Labor (p. 1085)
Stages of Labor (pp. 1085–1087)
Adjustments of the Infant to Extrauterine
Life
(p. 1087)
Taking the First Breath and Transition
(p. 1087)
Occlusion of Special Fetal Blood Vessels and
Vascular Shunts (p. 1087)
Lactation
(pp. 1087–1089)
Assisted Reproductive Technology and
Reproductive Cloning
(pp. 1089–1091)
1064
T
he birth of a baby is such a familiar event
that we tend to lose sight of
the wonder of this accomplishment: How does a single cell, the fertilized egg,
grow to become a complex human being consisting of trillions of cells? Te de-
tails of this process can fill a good-sized book. Our intention here is simply to outline
the important events of gestation and to consider briefly the events occurring imme-
diately aFer birth.
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