Search results for "Ground substance"
showing 6 items of 6 documents
Encapsulation Response ofCiona intestinalis(Ascidiacea) to Intratunical Erythrocyte Injection
1997
Abstract Electron microscopic studies on the encapsulation induced by erythrocyte injection into the tunic of the ascidian Ciona intestinalis were carried out. The observations reported in the present paper complete the description previously given of capsule architecture and contribute to the characterization of the cells involved in the inflammatory reaction. The inflamed area is surrounded by an ample and peculiar “three-layered coat” respectively composed of flattened and packed extratunical hemocytes, the monolayered epithelium, and a layer of intratunical electron-dense particles. The latter are also clustered, variously arranged, and distributed in the tunic ground substance. The epi…
Structure and closure mechanism of the human umbilical artery
1978
The structure of the fully-patent umbilical artery and rearrangement of its structural elements with postnatal closure were examined in 10 centimeter long umbilical cord segments which were double-clamped at different time intervals after delivery. The fully-patent umbilical artery consists of two main layers: an outer layer of circularly arranged smooth muscle cells and an inner layer which shows rather irregularly and loosely arranged cells embedded in abundant metachromatic ground substance. No predominantly longitudinal arrangements of cells and fibers reported by earlier investigators could be identified in the inner layer. Closure of the umbilical arteries is initiated by numerous loc…
Fine Structure of the Tunic ofCiona intestinalisL. II. Tunic morphology, cell distribution and their functional importance
1981
Ciona intestinalis L. tunic architecture and cell distribution were investigated with the electron microscope. The observations showed that the ascidian covering is formed by a thin outer cuticle, a subcuticle of variable width and a large single layer of ground substance. “Large granule”, morula, phagocyte and granulocyte are the cellular types encountered; they appear mainly in highly vacuolated states and are distributed throughout the whole tunic. The “large granule” cells, however, are mainly seen in the cuticle layer and the morula cells appear mostly in the outer zone of the ground substance. The role of these cells in tunic construction, repair and regeneration as well as their scav…
Cellular components and tunic architecture of the solitary ascidian Styela canopus (Stolidobranchiata, Styelidae).
1998
Abstract Cell distribution and tunic morphology in the ascidian Styela canopus were examined by electron microscopy. The observations showed that the outer covering is composed of a thin sinuous cuticle with several protrusions and a deep layer of ground substance. The fibrous component and its arrangement in the tunic were demonstrated: elementary fibrils exhibit a ‘microtubular’ structure and an elliptical cross-sectional shape. Four types of cells were described: clear vesicular tunic granulocytes, tunic microgranulocytes, unilocular tunic granulocytes, and globular tunic granulocytes. Morphofunctional aspects of the tunic tissue and certain phylogenetic relationships are discussed.
Studies on the Fibrous Components of the Test ofCiona intestinalisLinnaeus. I. Cellulose-like Polysaccharide
1977
Chemical, histochemical and electron microscopic studies on the fibrous polysaccharide component of the test of Ciona intestinalis L. were made. The results showed cellulose-like fibres to be present in the cuticle layer and in the ground substance. Bundles of fibres varying in diameter from 80 to 600 nm interweave to form a conspicuous network. The bundle appears to be formed of flat fibres, 10–13 nm in width, while the fibre is composed of fibrils 3.5–5 nm; the rectangular cross section of fibres can be supposed. The probable role of this polysaccharide is discussed.
Post-synovectomy changes in the articular cartilage
1978
Synovectomy of the left knee was performed in 37 immature rabbits, using the right knee for control. In the first set of experiments the articular cartilage was examined at weekly intervals for 8 weeks following the operation, paying particular attention to the metachromatic changes in the ground substance of the cartilage. In the second set of experiments, restoration of synovium was examined. In the third and fourth set of experiments, the uptake of S35 by the cartilage was assessed using autoradiography and densitometry. In the fifth set of experiments, alterations in S35 uptake by the chondrocitic cells of the cartilage were studied by electron microscopy.