Fertilised bird egg, cutaway illustration. This egg (from a chicken) has a yolk (yellow) and egg white (albumen), enclosed in an egg shell (white). Th

---

Fertilised bird egg, cutaway illustration. This egg (from a chicken) has a yolk (yellow) and egg white (albumen), enclosed in an egg shell (white). The egg shell and white are found in reptile eggs as well, but are absent or different in mammals. The developing embryo (microscopic in size here) is surrounded by an amniotic sac and amniotic fluid, encased in a membrane called the amnion. The embryo is nourished by the yolk, contained in its yolk sac. The egg includes structures to exchange gases and handle liquid waste. Surrounding the yolk is another membrane, the chorion. For a bird egg with a developing foetus, see image C040/3985.

---

Size: 3951px × 4429px
Photo credit: © CLAUS LUNAU/SCIENCE PHOTO LIBRARY / Alamy / Afripics
License: Licensed
Model Released: No

Keywords: -, albumen, amnion, amniotic, animal, artwork, background, biological, biology, bird, body, chicken, chorion, cut, cut-, cut-outs, cutaway, cutout, cutouts, developmental, egg, embryo, embryology, fauna, fertilised, fertilized, fluid, illustration, nature, ornithological, ornithology, outs, oval, sac, shell, white, wildlife, yolk, zoological, zoology