MadSci Network: Anatomy

Re: Do chickens use the same orfice to defecate that they use to lay eggs?

Date: Fri Apr 24 09:43:21 1998
Posted By: Michael Onken, MadSci Admin
Area of science: Anatomy
ID: 893377359.An

Birds, reptiles, amphibians, fish, and monotremes (platypuses and echidnas) all have their urogenital and alimentary tracts joined internally to form the cloaca (Klow-ay-kuh). The cloaca is a muscular sinus analogous to the rectum in higher mammals which allows the urine and fecal material to mix prior to excretion, which is why bird droppings contain both solid and liquid components. Since the oviducts which carry the eggs join the urethra as it enters the cloaca, the eggs must pass through the cloaca as well, as they are being layed. A cloaca forms during early human development, but is lost during later remodelling of the urogenital tract.

Current Queue | Current Queue for Anatomy | Anatomy archives

Try the links in the MadSci Library for more information on Anatomy.

MadSci Home | Information | Search | Random Knowledge Generator | MadSci Archives | Mad Library | MAD Labs | MAD FAQs | Ask a ? | Join Us! | Help Support MadSci

MadSci Network,
© 1995-1998. All rights reserved.