Abstract

Histoenzymic studies were conducted on the lymphoid tissue in tubal tonsil of six male crossbred goats of six months of age. Tonsillar lymphoid tissue could be located in the lateral wall of nasopharynx, ventral to the auditory tube opening. The surface epithelium of the tubal tonsil was of pseudostratified ciliated columnar type with basal, supporting and goblet cells. Above the dome of lymphoid nodules, the epithelium was modified into a follicle associated epithelium (FAE), also called lympho-pithelium. The surface of tubal tonsil showed folds and invaginations which formed crypts. The lamina propria-submucosa presented dome-like accumulation of primary and secondary lymphoid nodules. The tubal tonsil was not encapsulated. The fibroblastic reticular cell (FRC) in lamina propria were acidphosphatase (ACP) and alkaline phosphatase (ALP) positive and gave a reticular reaction in the parafollicular and internodular regions and linear reaction in the capsule of lymphatic nodules. The FRC around the lymphatic nodules and internodular regions, the follicular dendritic cells (FDC) in dome, corona and FAE and the B-cell area lymphocytes showed ATPase activity. The intercellular spaces between FAE and the basement membrane, internodular area and mantle zone of the lymphoid nodules showed alphanaphthyl acetate esterase (ANAE) activity in the cytoplasm of T-lymphocytes and macrophages. Both microscopic and histoenzymic studies suggested that the tubal tonsils were histologically mature as a local defence mechanism against the harmful substances to be encountered from the environment.
 

Keywords : Goats, histology, histochemistry, lymphoid tissue, tubal tonsil