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  • Electron microscopy  (4)
  • 1
    ISSN: 1432-0568
    Keywords: Parotid gland ; Miniature pig ; Electron microscopy ; Innervation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary This communication reports on the morphology of the parotid gland of miniature pigs (Göttingen strain). 1. The glandular system consists in its terminal portions of acinar secretory parts. Between the basal lamina and the secretory epithelial cells myoepithelial cells are located. 2. The cytoplasmic organization of the acinar cells represents the features of mucous secretory cells. By electron microscopic means, light secretory granules have been demonstrated which frequently are coalescent. Between the bulk of secretory material only small remnants of cytoplasm are visible. The electron dense nuclei are located in basal parts of the cells. Intercellular canaliculi have not been observed. 3. The intercalary ducts, located between the acinar portions and the striated ducts of the gland, are long and narrow tubules, frequently branched. Their epithelium is simple cuboidal, and there is no indication of any secretory activity. 4. The epithelium of the striated ducts is simple columnar. The orientation of mitochondria parallel to the cell axis, and also the invaginations of the basal cell membrane give the basal cytoplasm a vertically striated appearance. 5. The paravascular nerves of the gland's connective tissue consist of bundles of unmyelinated axons. These branch into smaller bundles, and finally into single unmyelinated axons which reach the acinar portions. These axons appear to be only partly surrounded by Schwann cells. Very thin axons alone penetrate the basal lamina and reach the secretory cells of the acini; moreover, these axons may occasionally reach the intercellular spaces between the secretory cells. Within these terminal parts of the axons groups of synaptic vesicles appear.
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  • 2
    ISSN: 1432-0878
    Keywords: Kidney ; Sexual segment ; Natrix natrix ; Histochemistry ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The sexual segment of the kidney of Natrix natrix has been investigated cytochemically, light microscopically and ultrastructurally. The sexual segment, which seems to be an important accessory sexual organ, has a single layer of a columnar epithelium. The epithelial cells are filled with large secretion granules of a wide range of electron densities. Cytochemical reactions for neutral and acid mucosubstances are negative, but the cells show a strong positive staining for phospholipids. Within the cells of the sexual segment we have localised by histochemical means several hydrolases and oxydoreductases, which reflect enzyme activities of the glycolytic pathway, the citrate cycle, and related metabolic pathways. The activities of the hydrolytic enzymes acid phosphatase, acetylcholinesterase and indoxylacetate esterase are remarkably high within the epithelial cells. Furthermore it was found that the sexual segment tubules possess contractile elements which extends over the basal surface of the epithelial cells. These contractile cells exhibit a very high activity of alkaline phosphatase. Single unmyelinated axons are located between the contractile elements and the basal lamina of the sexual segment cells. The functional significance of the sexual segment structures is briefly discussed.
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  • 3
    Electronic Resource
    Electronic Resource
    Springer
    Cell & tissue research 134 (1972), S. 435-438 
    ISSN: 1432-0878
    Keywords: Salt gland ; Birds ; Innervation ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The innervation of the salt gland of the goose, the duck and the swan was investigated by means of electron microscopy. Axonal swellings were observed in relationship to secretory cells as well as to central duct cells. The terminals contain synaptic and densecored vesicles. There are no specialized pre- and postsynaptic membranes.
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  • 4
    ISSN: 1432-0878
    Keywords: Glandula harderiana ; Anatidae ; Electron microscopy ; Cytochemistry
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Description / Table of Contents: Zusammenfassung Die Hardersche Drüse von Anser anser, Anas platyrhynchos und Cygnus olor wurde cytochemisch, licht- und elektronenmikroskopisch untersucht. Vergleichend-anatomisch ergibt sich für die drei Species derselbe Drüsenaufbau. Sie bestehen aus Läppchen bzw. kurzen Tubuli, die von einem einschichtigen, hochprismatischen Epithel ausgekleidet sind, das sich auf die in die Tubuli hineinragenden Leisten bzw. Zotten fortsetzt. Es müssen zentrale und periphere Drüsenabschnitte unterschieden werden. Nur die zentralen Zellen enthalten neutrale und saure Mukosubstanzen. In Semidünnschnitten (Richardson) erweisen sich die peripheren Drüsenzellen als stark vakuolisiert. Zentralwärts nimmt die Vakuolisierung ab, die basale Basophilie nimmt zu. In den Harderschen Drüsen von Gänsen und Enten wurden neben Hydrolasen eine Reihe von Oxydo-Reduktasen aus der Glykolysekette, dem Citratzyklus und der Atmungskette sowie die Enzyme G-6-PDH, GDH, β-HBDH und GLuDH nachgewiesen. Die zentralen Drüsenabschnitte sind mit hohen Aktivitäten der glykolytischen Oxydo-Reduktasen und der NADPH2-liefernden Enzyme ausgestattet. Hydrolytische lysosomale Enzyme, Esterasen und Phosphatasen sind in der Harderschen Drüse nur in geringer Menge vorhanden. Stets können cholinerge Nerven nachgewiesen werden. — Elektronenmikroskopie: Alle Drüsenzellen werden an den apikalen seitlichen Kontaktflächen durch ein differenziertes Schlußleistennetz (Zonulae occludentes, Zonulae adhaerentes, Desmosomen) verbunden. An den zentralen Drüsenzellen lassen sich eine Basalzone (Zellkern, ER), eine ausgedehnte Golgi-Zone und ein apikales Zell-areal unterscheiden. Die Sekretvakuolen entstehen durch Membranabknospung aus dem Golgi-Apparat, ihr Sekret wird durch Ruptur des apikalen Plasmalemms extrudiert. Die peripheren Drüsenzellen weisen strukturelle Merkmale von Becherzellen auf. Ein schmaler basaler Cytoplasmabezirk enthält den komprimierten Kern, der übrige Zellraum überwiegend leere Vakuolen, Membranreste, Lamellenkörper und Lysosomen. Terminale Nervenfasern mit bekannter Innenstruktur durchbrechen die Basalmembran und lagern sich den Drüsenzellen eng an, teilweise in Vertiefungen ihrer basalen und basolateralen Oberfläche eingebettet. Diese terminalen Axone enthalten massenhaft synaptische Vesikel, vereinzelt Bläschen mit einem massendichten Granulum und Mitochondrien. Spezialisierte prae- und postsynaptische Membranen kommen nicht vor.
    Notes: Summary The Harderian gland of Anser anser, Anas platyrhynchos and Cygnus olor has been investigated cytochemically, light microscopically and ultrastructurally. Comparison of these glands within the three species reveals identical structures. The surface of the short glandular tubules carries a single-layered, cylindrical epithelium, which continuously covers all the villi protruding into the tubular lumen. There is evidence for a significant difference between the central and peripheral parts of the glandular tubules. Cytochemical reactions for neutral and acid mucosubstances are positive only in central glandular parts. The semi-thin sections (Richardson staining) show highly vacuolated glandular cells within the peripheral areas. This vacuolisation decreases the more centrally the cells are situated, but conversely their basal basophilic staining increases towards the center. Within the Harderian gland of geese and ducks we have localized by histochemical means several hydrolases and oxydoreductases which reflect enzyme activities of the glycolytic pathway, the citrate cycle, and related metabolic pathways. The activities of glycolytic oxydoreductases and the pentose phosphate pathway enzymes are remarkably high within the central glandular parts. Lysosomal hydrolases, esterases and phosphatases are only to be demonstrated in very moderate degree of activity. All specimens of the Harderian gland contain cholinergic nerves. The ultrastructural analysis reveals highly differentiated apical cellular contacts (zonulae adhaerentes, desmosomes). There are only small intercellular spaces. The centrally located glandular cells can be divided into three compartments, a basal zone containing the nucleus and endoplasmic reticulum, a large Golgi zone and an apical zone containing abundant secretory vacuoles, which emerge from the Golgi apparatus. The secretory products are extruded by rupture of the apical cellular membrane. — The peripheral glandular cells show many similarities to goblet cells. There is only a small basal cytoplasmic are which contains a compressed nucleus, whereas the whole cell is filled with mostly empty vacuoles, membranes, lamellar bodies and lysosomes. — Terminal nerve fibres penetrate the basal lamina and make contact with the glandular cells. The terminal axons contain abundantly synaptic vesicles, sporadic dense cored vesicles and mitochondria. Until now, we could not find any specialized presynaptic or postsynaptic membranes.
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