SPLENIC MICROVASCULARIZATION OF THE BEAUTIFUL SQUIRREL, CALLOSCIURUS FINLAYSONI

摘要

The vascular pattern in the spleen is a controversial topic, whether it is a closed or an open type. In addition, there is no report on the microvascularization of the spleen in the beautiful squirrel, Callosciurus finlaysoni (Horsfield, 1824) which is classified in the mammals. Consequently, it is interesting to investigate the splenic microcirculation in this animal by using vascular corrosion cast with scanning electron microscope (SEM) that is a suitable technique showing the microangioarchitccture in three dimensions. Ten adult animals of both sexes, weighing ranged 120 to 180 g, were processed by using vascular corrosion cast technique. The replicas of the splenic microvasculature were observed under SEM. It was found that the main artery supplying the spleen was splenic artery. These vessels deeply penetrated into the spleen at its hilus before dividing into trabecular arteries. Each trabecular artery spilted into several central arterioles that passed into the white pulp. Each central arteriole was situated eccentrically in the white pulp, and sent out radiating penicillar arterioles. The terminal ends of these arterioles or arterial capillaries could either be divided into the marginal sinusoids or be directly continued toward the red pulp sinusoids. These sinusoids emptied into pulp venules, which were collected into trabecular veins. Finally, these trabecular veins drained into splenic veins. Due to the direct continuation of the arterial capillaries with the red pulp sinusoids, it comes to the conclusion that the splenic blood pattern of this beautiful squirrel is truly a closed circulation.