scholarly journals The Anatomy of Secretion in the Follicular Cells of the Thyroid Gland

1960 ◽  
Vol 7 (3) ◽  
pp. 419-432 ◽  
Author(s):  
Steven L. Wissig
Keyword(s):  
Fine Structure ◽  
Thyroid Gland ◽  
Epithelial Cells ◽  
Golgi Apparatus ◽  
Basement Membrane ◽  
Particulate Material ◽  
Capillary Endothelium ◽  
Follicular Cells ◽  
Normal Rat ◽  
Membrane Bound

The paper contains a description of the fine structure of the thyroid gland of the normal rat. The follicular colloid, a homogeneous substance of faintly granular texture, is bounded by cuboidal or low columnar epithelial cells. Numerous pleomorphic microvilli, often permeated by small vesicles extend from the apices of the epithelial cells into the colloid. Many small, membrane-limited vesicles lie in the superficial cytoplasmic layer just below the apical plasmalemma. The ergastoplasmic sacs of the follicular cells are dilated and contain a substance resembling colloid. They are of irregular outline, and the larger sacs tend to be located in the base of the cells. The Golgi apparatus lies in the vicinity of the nucleus and consists primarily of numerous small, membrane-bound droplets with a homogeneous content. Droplets, similar to the Golgi vesicles but larger, lie in the same vicinity and are tentatively identified as colloid droplets. The colloid droplets contain an extremely fine, dense particulate material. Other droplets with a denser, more heterogenous content are also present. Both the follicular cells and the perifollicular capillaries are bounded by a continuous basement membrane. The capillary endothelium is in certain regions extremely attenuated and is pierced by numerous patent pores, 450 A in diameter. The marked similarity between the presumptive colloid droplets and vesicles of the Golgi apparatus suggests that the droplets arise from this organelle. On morphological grounds alone no relation can be established between any of the organelles of the follicular cell and the process of colloid resorption.

Fine structure and development of schizonts, merozoites and macrogamonts of Eimeria acervulina in the goblet cells of the duodenal epithelium of experimentally infected birds

Parasitology ◽  
1975 ◽  
Vol 70 (2) ◽  
pp. 223-229 ◽  
Author(s):  
E. Michael
Keyword(s):  
Fine Structure ◽  
Epithelial Cells ◽  
Golgi Apparatus ◽  
Host Cell ◽  
Goblet Cells ◽  
Cellular Level ◽  
Site Specificity ◽  
Eimeria Acervulina ◽  
Duodenal Epithelium

The fine structure of trophozoites, schizonts, merozoites and macrogamonts of Eimeria acervulina found in goblet cells of the duodenal epithelium of chicks is described and compared with the corresponding stages formed in other epithelial cells. Complete schizogony, with the formation of mature merozoites, occurred freely in goblet cells. Developing macrogamonts (but no microgamonts) were rarely found in goblet cells. The stages observed were confined to the cytoplasm of the host cell above the Golgi apparatus and were usually seen between the mucous granules. The stages seen appeared normal, and contained similar structures to corresponding stages developing in other cells. The finding of developing stages of E. acervulina in goblet cells provides further evidence that site specificity of Eimeria at the cellular level is not as strict as previously thought.

Some Aspects of the Cytology of Polycelis nigra

1961 ◽  
Vol s3-102 (59) ◽  
pp. 295-317
Author(s):  
R. J. SKAER
Keyword(s):  
Fine Structure ◽  
Epithelial Cells ◽  
Basement Membrane ◽  
Muscle Fibre ◽  
Cell Body ◽  
Basal Body ◽  
Sense Organs ◽  
Gland Cells ◽  
Secretion Granules ◽  
Undifferentiated Cells

The triclad, Polycelis nigra, has been found to be fully cellular. Gland-cells, undifferentiated cells, and the cell-bodies of muscle-cells, make up the parenchyma. The fine structure of the component cells of the parenchyma, nervous, and excretory systems, testis, pharynx, and epidermis is described. Acidophil secretion granules, produced by certain parenchymatous gland-cells, have a characteristic, doubly-banded ultrastructure which is not invariably associated with the property of adhesiveness. The parenchymatous cell-body of the muscles is often up to 10 µ. from the musclefibre, to which it is joined by tenuous cytoplasmic connexions. The muscle-fibre itself consists of coarse and fine sets of hexagonally arranged myofilaments, but is unhanded. The basement membrane of the epidermis is composed of fine, banded fibrils, apparently randomly arranged in the plane of the membrane. Permeating the epidermis at a level just above the basement membrane is a system of extracellular spaces, which may have a hydrostatic function and assist in the extrusion of secretion granules. Epidermal sense organs, whose fine structure resembles the basal body of the cilia, are considered to have a functionally significant distribution on the surface of the animal. The rhabdites have been shown to develop in special cells of the parenchyma. Such rhabdite-forming cells, together with their contained rhabdites, have been found apparently passing through the basement membrane of the epidermis. As all the epidermal epithelial cells contain rhabdites, it is suggested that the epidermis as a whole is renewed by centrifugal migration of rhabdite-forming cells. The rhabdites themselves appear to consist of arginine and some tyrosine, together with a purine, probably adenine. They may be an excretory product.

scholarly journals Inwardly rectifying K+ channel Kir7.1 is highly expressed in thyroid follicular cells, intestinal epithelial cells and choroid plexus epithelial cells: implication for a functional coupling with Na+,K+-ATPase

1999 ◽  
Vol 342 (2) ◽  
pp. 329-336 ◽  
Author(s):  
Nobuhiro NAKAMURA ◽  
Yoshiro SUZUKI ◽  
Hidenari SAKUTA ◽  
Kayoko OOKATA ◽  
Katsumasa KAWAHARA ◽  
...  
Keyword(s):  
Thyroid Gland ◽  
Epithelial Cells ◽  
Choroid Plexus ◽  
Basolateral Membrane ◽  
K Channel ◽  
Functional Coupling ◽  
Follicular Cells ◽  
Rat Thyroid ◽  
Pore Properties ◽  
Inwardly Rectifying

A novel inwardly rectifying K+ channel, Kir7.1, with unique pore properties, was cloned recently. Working in the field of osmoregulation, we have also identified the same human and rat channel and found that the channel is unique not only in its pore sequence but also in its dense localization in the follicular cells of the thyroid gland. Northern blot analysis revealed that the channel message was abundantly expressed in the thyroid gland and small intestine, and moderately in the kidney, stomach, spinal cord and brain. Immunohistochemistry of the rat thyroid, intestine and choroid plexus demonstrated the expression of the channel protein in the follicular cells and epithelial cells, suggesting a role in the regulation of the ion-transporting functions of these specialized cells. The unique pore properties of Kir7.1 make it a strong candidate for the hypothetical low-conductance K+ channel that is functionally coupled with Na+,K+-ATPase by recycling K+. We therefore further examined the co-localization of Kir7.1 and Na+,K+-ATPase and found that both are localized in the basolateral membrane of the thyroid follicular cell; in the choroid plexus, which is known to be unique in having Na+,K+-ATPase in the apical side of the epithelial cells, Kir7.1 was found in the apical membrane, implying a close functional coupling between the channel and Na+,K+-ATPase.

GROWTH IN THE CELL POPULATIONS OF THE THYROID GLAND OF RATS TREATED WITH THIOURACIL

1957 ◽  
Vol 15 (2) ◽  
pp. 151-161 ◽  
Author(s):  
JOYCE E. SANTLER
Keyword(s):  
Tissue Culture ◽  
Thyroid Gland ◽  
Epithelial Cells ◽  
Cell Population ◽  
Stromal Cells ◽  
Stromal Cell ◽  
Cell Populations ◽  
Follicular Cells ◽  
Albino Rat ◽  
Thyroid Glands

SUMMARY The effect of thiouracil administration on the numbers of the follicular and stromal cells in the thyroid gland of the male albino rat was investigated. Both were found to increase in number, but a relatively greater increase occurred in the stromal cell population than in that of the follicular cells. The mitotic rates for both types of cell were estimated. The maximum mitotic rates were seen in the group that had received 6 day's thiouracil treatment, after which there was a decline. A difference between the effect of the fixatives, Carnoy and Zenker-acetic, on treated and nontreated thyroid glands was noted, more shrinkage occurring when treated glands were fixed in Zenker-acetic. Tissue-culture experiments showed an increase in the numbers of both epithelial cells and fibroblasts migrated outwards from explants from stimulated glands.

Pituitary Follicular Cells: Their Origin, Possible Function and Fate

1974 ◽  
Vol 32 ◽  
pp. 34-35
Author(s):  
E. Horvath ◽  
K. Kovacs ◽  
G. Penz ◽  
C. Ezrin
Keyword(s):  
Fine Structure ◽  
Secretory Granules ◽  
Follicular Cells ◽  
Human Pituitary ◽  
Rat Pituitary ◽  
Pituitary Glands ◽  
Junctional Complexes

Follicular structures, in the rat pituitary, composed of cells joined by junctional complexes and possessing few organelles and few, if any, secretory granules, were first described by Farquhar in 1957. Cells of the same description have since been observed in several species including man. The importance of these cells, however, remains obscure. While studying human pituitary glands, we have observed wide variations in the fine structure of follicular cells which may lead to a better understanding of their morphogenesis and significance.

Intranuclear Crystals in Regenerating Canine Kidneys

1973 ◽  
Vol 31 ◽  
pp. 412-413
Author(s):  
D.G. Osborne ◽  
L.J. McCormack ◽  
M.O. Magnusson ◽  
W.S. Kiser
Keyword(s):  
Epithelial Cell ◽  
Epithelial Cells ◽  
Tubular Epithelial Cell ◽  
Tubular Epithelial Cells ◽  
Cell Nuclei ◽  
Crystalline Structures ◽  
Small Crystals ◽  
Membrane Bound

During a project in which regenerative changes were studied in autotransplanted canine kidneys, intranuclear crystals were seen in a small number of tubular epithelial cells. These crystalline structures were seen in the control specimens and also in regenerating specimens; the main differences being in size and number of them. The control specimens showed a few tubular epithelial cell nuclei almost completely occupied by large crystals that were not membrane bound. Subsequent follow-up biopsies of the same kidneys contained similar intranuclear crystals but of a much smaller size. Some of these nuclei contained several small crystals. The small crystals occurred at one week following transplantation and were seen even four weeks following transplantation. As time passed, the small crystals appeared to fuse to form larger crystals.

scholarly journals CHANGES IN FINE STRUCTURE DURING SILK PROTEIN PRODUCTION IN THE AMPULLATE GLAND OF THE SPIDER ARANEUS SERICATUS

1969 ◽  
Vol 42 (1) ◽  
pp. 284-295 ◽  
Author(s):  
Allen L. Bell ◽  
David B. Peakall
Keyword(s):  
Fine Structure ◽  
Epithelial Cells ◽  
Protein Production ◽  
Distal Portion ◽  
Silk Gland ◽  
The Body ◽  
Single Type ◽  
Secretory Cells ◽  
The Web ◽  
Tunica Intima

The ampullate silk gland of the spider, Araneus sericatus, produces the silk fiber for the scaffolding of the web. The fine structure of the various parts of the gland is described. The distal portion of the duct consist of a tube of epithelial cells which appear to secrete a substance which forms the tunica intima of the duct wall. At the proximal end of the duct there is a region of secretory cells. The epithelium of the sac portion contains five morphologically distinct types of granules. The bulk of the synthesis of silk occurs in the tail of the gland, and in this region only a single type of secretory droplet is seen in the epithelium. Protein synthesis can be stimulated by the injection of 1 mg/kg acetylcholine into the body fluids. 10 min after injection, much of the protein stored in the cytoplasm of the epithelial cells has been secreted into the lumen. 20 min after stimulation, the ergastoplasmic sacs form large whorls in the cytoplasm. Protein, similar in electron-opacity to protein found in the lumen, begins to form in that portion of the cytoplasm which is enclosed by the whorls. The limiting membrane of these droplets is formed by ergastoplasmic membranes which lose their ribosomes. No Golgi material has been found in these cells. Protein appears to be manufactured in the cytoplasm of the tail cells in a form which is ready for secretion.

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