Skip Navigation
The Endowment for Human Development
The Endowment for Human Development
Improving lifelong health one pregnancy at a time.
Donate Now Get Free Videos

Slideshow: Umbilical Cord, Placenta & More

Yolk Sac

#83, Slide 8 of 35

5 weeks, 6 days

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.
Free resources and training for educators
Help give babies a healthy start and a healthy future. Donate now.