What is a mammalian equivalent of the cloaca?

What is a mammalian equivalent of the cloaca?

• A. The pharynx and larynx
• B. The pyloric sphincter
• C. The anus and urethra
• D. The bile and pancreatic ducts

Answer: (C)

In mammals, the single cloaca found in many other vertebrates is not present. Instead, the digestive and urinary (and reproductive) tracts terminate at separate external openings. The digestive wastes leave through the anus, while urine exits via the urethra; reproductive products exit separately through the appropriate reproductive openings. So the mammalian equivalent conceptually is the combination of an opening for the anus and a separate urethral opening. The other options describe structures not related to how mammalian waste and urine exit the body.

In mammals, the single cloaca found in many other vertebrates is not present. Instead, the digestive and urinary (and reproductive) tracts terminate at separate external openings. The digestive wastes leave through the anus, while urine exits via the urethra; reproductive products exit separately through the appropriate reproductive openings. So the mammalian equivalent conceptually is the combination of an opening for the anus and a separate urethral opening. The other options describe structures not related to how mammalian waste and urine exit the body.