Slideshow: Umbilical Cord, Placenta & More

Yolk Sac

#83, Slide 8 of 35

5 weeks, 6 days

From The Biology of Prenatal Development.

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.

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