cloaca

cloaca

 [klo-a´kah] (pl. cloa´cae) (L.)

1. a common passage for fecal, urinary, and reproductive discharge in most lower vertebrates.

2. in mammalian embryos, the terminal end of the hindgut before division into rectum, bladder, and the primordia of the reproductive organs.

3. an opening in the covering or sheath of a necrosed bone. adj., adj cloa´cal.

clo·a·ca

(klō-ā'kă),

1. In early embryos, the endodermally lined chamber into which the hindgut and allantois empty.

2. In birds and monotremes, the common chamber into which open the hindgut, bladder, and genital ducts.

[L. sewer]

cloaca

(klō-ā′kə)

n. pl. cloa·cae (-sē′)

Zoology

a. The common cavity that serves as the opening for the intestinal, genital, and urinary tracts in many vertebrates, including amphibians, reptiles, birds, monotremes, and some fishes.

b. The posterior part of the intestinal tract in various invertebrates.

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clo·a′cal (-kəl) adj.

cloaca

Embryology
The terminal hindgut before it divides into the rectum, bladder and genital primordia.
 
Pathology
An obsolete term for an opening in the involucrum of necrotic bone.
 
Zoology
A common conduit in most lower vertebrates for faecal, urinary and reproductive discharge.

clo·a·ca

, pl. cloacae (klō-ā'kă, -sē)

1. In early embryos, the endodermally lined chamber into which the hindgut and allantois empty.

2. In birds and monotremes, the common chamber into which the hindgut, bladder, and genital ducts empty.

[L. sewer]

cloaca

The combined urinary and faecal opening in the embryo before the two become separated. The term derives from the Latin cloaca a sewer.

cloaca

the terminal part of the gut system of most vertebrates (except higher mammals) into which the ducts from the kidney and reproductive system open. In these types there is thus only one posterior aperture to the body as compared with two in mammals, the anus and the opening of the urinogenital system. In some vertebrates, such as birds, the cloaca is reversible and forms a penis-like structure in the males during copulation.