Some notes on the pancreas of franciscana (la plata dolphin), pontoporia blainvillei

Abstract

Macro- and light microscopic anatomical observations were described for the pancreas of twelve Pontoporia blainvillei (body length 84.5-160 cm), especially regarding their unique form and location in the abdominal cavity and the cell constituent of islets of Langerhans. The greater part of the pancreas of Pontoporia is seen as a flat sheet, being enclosed in the dorsal leaf of the omentum majus. This feature is quite different from that of other cetaceans whose pancreas lie retroperitoneally as in other mammals. The ratio of pancreas weight to body weight in Pontoporia is approximately 0.27% which seems to be similar to those of small cetaceans. The light microscopical structure of Pontoporia's pancreas is similar to that of man. The acinous cells of the exocrine portion have usual features and intercalated ducts are well developed. Striated ducts were not observed. The islets of Langerhans are small in diameter (65 μ in average) and the ratio of A to B cells was about 1: 2. Having fewer A cells than other adult mammals seems to be one of the characteristics of cetaceans. © 1975, Editorial Board of Okajimas Folia Anatomica Japonica. All rights reserved.