Electron microscopical studies on the thyroid of a cyclostome, Lampetra japonica, during its upstream migration.

摘要: Electron microscopical studies were made of the thyroid gland an adult lamprey, Lampetra japonica, in upstream migration period. The consists many usual follicles containing colloid their lumina, and a large parafollicle without colloid. paper concerns only follicle. follicle cells found wall are classified into three types; 1. non-ciliated taller cell, 2. ciliated one, 3. cuboidal one. From cytoplasmic fine structure, it is considered that all these essentially identical differences among them due to functional state. All type characterized by irregularly developed interdigitations aggregates tonofilaments throughout cytoplasm, especially perinuclear region. Although rough-surfaced endoplasmic reticulum Golgi apparatus fairly well first second cells, cisternae not so large-vacuolated but flattened, cytoplasm more compact as compared with higher vertebrate. In third cytomembranes poorly developed. Large dense inclusion-bodies consisting heterogeneously materials, lamellar structures, less vacuoles, which often also characteristic for lamprey thyroid. body might be intimately related kind lysosomes perhaps corresponds yellow pigment observed light microscopy. apical part there kinds granules or vesicles; numerous small vesicles derived from apparatus, few seem originate region, less-dense granules. those cells. bodies very number. Around thyroid, basement membrane relatively connective tissue blood capillaries. Characteristic fat tissue.