Bursa of Fabricius(redirected from bursas of Fabricius)
Also found in: Dictionary, Medical.
bursa of Fabricius[′bər·sə əv fə′brēsh·əs]
Bursa of Fabricius
(named after G. Fabricius), a pouchlike thick-walled formation in birds, situated on the dorsal surface of the rear section of the cloaca. The bursa of Fabricius is well developed in all young birds until they reach sexual maturity, at about eight or nine months, when it becomes reduced. Rheas are the only birds in which it does not become reduced. The function of the bursa of Fabricius has not been clearly established; lymphatic cells and oxyphile leucocytes are formed inside it.