Ultrastructure of the pineal organ of Crypturellus parvirostris Wagler, 1897 (Aves. Tinamiformes)
Redins, C.A.; Machado, A.B.
Revista Brasileira de Biologia 44(4): 499-508
1984
ISSN/ISBN: 0034-7108 PMID: 6537598 Document Number: 226472
The pineal organ of the tinamid bird Crypturellus parvirostris was studied with the electron microscope. The organ exhibits a follicular organization with two types of cells: rudimentary photoreceptors cells (A cells) and supporting cells (B cells). The A cells resemble photoreceptors except for the asynaptic basal pedicle and for the outer segment represented by a dilated cilia type 9 + 0 (bulbous-cilio). Thus no morphological evidence for conventional photoreceptor function was found in the pineal organ of C. parvirostris, although it belongs to a group of very primitive birds. On the other hand, the presence of a large Golgi complex, dilated cisternae of rough endoplasmic reticulum and abundant dense cored vesicles are indicative of an intense secretory activity. The presence of a moderate number of coated vesicles in relation to the membrane of the apical process suggests an interaction between these proceses and the substance inside the follicles.