Microcirculatory patterns in human pancreas: supplementary observations of vascular casts by scanning electron...

The blood vascular bed of two human pancreata was replicated partially by arterial perfusion of intentionally reduced amounts of low viscosity methacrylate resin, to be observed with a scanning electron microscope. The findings were compared with those obtained from a pancreas replicated completely by a sufficient amount of resin. Complete replication confirmed our previous findings (MURAKAMI et al., 1992) that many exocrine lobules contained one or more endocrine islets, which preferentially issued insulo-acinar portal vessels continuous with the lobular capillaries. Incomplete replication demonstrated that the casting medium filled blood capillaries in the endocrine islets more promptly than those in the exocrine lobules and secretory ducts. Furthermore, islet-containing lobules allowed a more rapid resin flow to the exocrine tissue via the insulo-acinar portal route than did the lobules lacking an islet. Since the resin medium used had the viscosity of blood and was injected under physiological pressure, the results obtained by the incomplete arterial injections are believed to suggest the physiological state of blood flow in the pancreas.