Zoology: General

A Dictionary of Zoology A Dictionary of Biology A Dictionary of Nursing Further reading

allantois

A Dictionary of Zoology | 1999 | | Copyright

allantois In tetrapod embryos, a sac formed by the outgrowth of the posterior ventral part of the gut, as a precocious urinary bladder. In reptiles and birds it grows to surround the embryo, lying between the yolk sac and shell; the blood vessels by which it is linked to the embryo provide the means of respiration, and the allantoic cavity receives metabolic wastes. Most of the allantois is left with the shell at hatching. In Eutheria the allantois forms part of the placenta, supplying it with blood for respiration, nutrition, and excretion, and the allantoic cavity may be small. Most of the allantois is detached from the embryo at birth.

Cite this article
Pick a style below, and copy the text for your bibliography.

MLA
Chicago
APA

MICHAEL ALLABY. "allantois." A Dictionary of Zoology. 1999. Encyclopedia.com. 30 May. 2012 <http://www.encyclopedia.com>.

MICHAEL ALLABY. "allantois." A Dictionary of Zoology. 1999. Encyclopedia.com. (May 30, 2012). http://www.encyclopedia.com/doc/1O8-allantois.html

MICHAEL ALLABY. "allantois." A Dictionary of Zoology. 1999. Retrieved May 30, 2012 from Encyclopedia.com: http://www.encyclopedia.com/doc/1O8-allantois.html

Learn more about citation styles

allantois

A Dictionary of Biology | 2004 | Copyright

allantois One of the membranes that develops in embryonic reptiles, birds, and mammals as a growth from the hindgut. It acts as a urinary bladder for the storage of waste excretory products in the egg (in reptiles and birds) and as a means of providing the embryo with oxygen (in reptiles, birds, and mammals) and food (in mammals; see placenta). See also extraembryonic membranes.

Cite this article
Pick a style below, and copy the text for your bibliography.

MLA
Chicago
APA

"allantois." A Dictionary of Biology. 2004. Encyclopedia.com. 30 May. 2012 <http://www.encyclopedia.com>.

"allantois." A Dictionary of Biology. 2004. Encyclopedia.com. (May 30, 2012). http://www.encyclopedia.com/doc/1O6-allantois.html

"allantois." A Dictionary of Biology. 2004. Retrieved May 30, 2012 from Encyclopedia.com: http://www.encyclopedia.com/doc/1O6-allantois.html

Learn more about citation styles

allantois

A Dictionary of Nursing | 2008 | Copyright

allantois (al-ăn-toh-iss) n. the membranous sac that develops as an outgrowth of the embryonic hindgut. Its outer (mesodermal) layer carries blood vessels to the placenta and so forms part of the umbilical cord.
—allantoic adj.

Cite this article
Pick a style below, and copy the text for your bibliography.

MLA
Chicago
APA

"allantois." A Dictionary of Nursing. 2008. Encyclopedia.com. 30 May. 2012 <http://www.encyclopedia.com>.

"allantois." A Dictionary of Nursing. 2008. Encyclopedia.com. (May 30, 2012). http://www.encyclopedia.com/doc/1O62-allantois.html

"allantois." A Dictionary of Nursing. 2008. Retrieved May 30, 2012 from Encyclopedia.com: http://www.encyclopedia.com/doc/1O62-allantois.html

Learn more about citation styles

Free newspaper and magazine articles

	Bio-tolerance of textile implants.(Prostheses) Newspaper article from: Medical Textiles; 9/1/2010
	Girl kidnapped in broad daylight. Newspaper article from: The Nation (Karachi, Pakistan); 7/9/2011
	The micturating umbilicus.(Clinical Images)(Clinical report) Magazine article from: South African Medical Journal; 1/1/2010