allantois
Sign in to saveThe allantois ( ; : allantoides or allantoises) is one of the four membranes of the extraembryonic tissue arising from the yolk sac. It is a hollow sac-like structure filled with clear fluid that forms part of the developing conceptus in an amniote that helps the embryo exchange gases and handle liquid waste. The other extraembryonic membranes are the yolk sac, the amnion, and the chorion. In mammals these membranes are known as fetal membranes.
Key facts
- Embryology.Caption
- Diagram illustrating a chicken egg in its 9th day with all extraembryonic membranes
- Embryology.Image2
- FetalMembranes1L.jpg
- Embryology.Caption2
- Allantois and other fetal membranes shown at end of second month of human pregnancy
- Embryology.Days
- 16
- Embryology.Pronunciation
- ,
- Embryology.Name
- Allantois
- Embryology.Latin
- allantois
- Embryology.Image
- Chicken egg diagram.svg
via Wikipedia infobox
Research
2,136 papers- The mouse allantois: new insights at the embryonic-extraembryonic interface.Philosophical transactions of the Royal Society of London. Series B, Biological sciences · 2022
- The murine allantois.Current topics in developmental biology · 1998
- The murine allantois: a model system for the study of blood vessel formation.Blood · 2012
- Allantois and placenta as developmental sources of hematopoietic stem cells.The International journal of developmental biology · 2010
- The Allantois and Urachus: Histological Study Using Human Embryo and Fetuses.Fetal and pediatric pathology · 2022
via PubMed
Article
8 sectionsContents
- Function
- In mammals
- In marsupials
- In reptiles and birds
- Clinical significance
- Additional images
- References
- External links
The allantois ( ; : allantoides or allantoises) is one of the four membranes of the extraembryonic tissue arising from the yolk sac. It is a hollow sac-like structure filled with clear fluid that forms part of the developing conceptus in an amniote that helps the embryo exchange gases and handle liquid waste. The other extraembryonic membranes are the yolk sac, the amnion, and the chorion. In mammals these membranes are known as fetal membranes.
The allantois, along with the amnion, chorion, and yolk sac (other extraembryonic membranes), identify humans and other mammals, birds, and reptiles as amniotes. These extraembryonic membranes that form the embryo have aided amniotes in the transition from aquatic to terrestrial environments. Fish and amphibians are anamniotes, lacking the allantois.