Cloacal Bursa of Chicken

The cloacal bursa of Fabricius in birds is a lymphoid organ in the cloaca. Mucosal folds (pleicae) project into the lumen of the bursa. Numerous lymphoid nodules (follicles) are found in the lamina propria of each fold. Each nodule has a darker cortex with densely packed small lynphocytes and a lighter staining, less dense medulla containing cells of various sizes. The lymphoid cells of the bursa are cof the B-cell lineage. Oirginal mag. 13x Azure-Eosin. Cloacal bursa of Fabricius. Lymphoid System. Chicken.