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The Endowment for Human Development
The Endowment for Human Development
Improving lifelong health one pregnancy at a time.
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Yolk Sac

5 weeks, 6 days

Yolk Sac [Click for next image]
From The Biology of Prenatal Development.Buy Now

Note:

The yolk sac contains no yolk. However, early in pregnancy the yolk sac absorbs nutrients from the surrounding fluid (provided by the mother) and delivers them to the embryo. Thanks mom!

Label Key:

1. yolk sac
2. vitelline vessels
All ages referenced to fertilization, not last menstrual period.
The Vital Organs
The Vital Organs
Yolk Sac and Vitelline Vessels
Yolk Sac and Vitelline Vessels
Yolk Sac
Yolk Sac
The Beating Heart
The Beating Heart
Hand Plate and Vital Organs
Hand Plate and Vital Organs
Left Hand Plate and Wrist
Left Hand Plate and Wrist
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