GLÂNDULA DIGESTIVA DE MYTELLA GUYANENSIS (BIVALVIA: MYTILIDAE) - TÚBULOS E DUCTOS

Abstract

Mytella guyanensis samples (ten animals) were collected every two hours intervals over a 12 hour period, fixed in paraformaldehyde, imbedded in historesin, sliced in 1 µm thickness, and stained in haematoxilin/eosin. Digestive gland showed to be exocrine and a tubular-composed type. The conducting portion is formed by ducts: the "primary" ones show a wide irregular lumen, slightly flattened with a marked ventral groove, and a slight dorsal groove and two intermediate lateral grooves. Dorsal cells are cylindrical with well developed microvilli and intervilli. Ventral cylindrical cells are very high, with microvilli in the outside of typhlosole and flagellum in the inside and cilia inthe ventral groove. The "secondary" ducts show a small regular lumen, with large microvilli andintervilli in the cylindrical cells. The secreting part is formed by blind ended digestive tubules, slightly dilated in the distal third. The lateral walls are formed by basophilic cells from the germinative line (cubic and cylindrical basophilic cells), with basophilic cells from the secretive line(pyramidal basophilic cells and mature basophilic cells) as well as the acidophilic cells from the digestive line (cylindrical acidophilic and mature acidophilic cells).