Ultrastructural Study of Secretory Granules in the Juxtaglomerular Cells -Particularly on Formation and Extrusion-

The secretory granules in the juxtaglomerular cells which are believed to be renin or renin-like substance are of experimental and clinical interest since they are related to hypertension and Na balance. Electron microscopic observations were made with rats on the mechanism of formation and extrusion of secretory granules upon giving stimulation to the juxtaglomerular cells by means of restricted salt diet and administration of diuretics. As to the formation of granules, rough-surfaced endoplasmic reticulum developed into Golgi apparatus, immature granules and finally mature granules. At least, one of the extrusion types was diacrine mechanism since there was observed "fading" of granule content while the limit membrane was maintained. In view of the fact that extrusion by diacrine mechanism is generally of the substance of low molecular weight, it is presumed that the content of JG cell might be prmitive renin of relatively low molecular weight or might possibly include some substance other than renin

Applying Learner-centered Education in College Classrooms

Teacher-centere instruction seems to be the norm in many colleg classrooms. In this approach, the focus of the instruction is on how much knowledge students recall rather than how they think, apply and transfer Knowledge in different contexts. This article attempts to show how learner-centered education helps students focus on activities and assignments which are related to their own learning skills. The writer also explores the importance of placing responsibility on the learners, knowing their capabilities and creating environments to help them make connections in their own learning