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  • Hirudo medicinalis  (2)
  • Connective tissue  (1)
  • Orconectes limosus (Crustacea)  (1)
  • 1
    Digitale Medien
    Digitale Medien
    Springer
    Development genes and evolution 202 (1993), S. 329-340 
    ISSN: 1432-041X
    Schlagwort(e): organogenesis ; excretory organ ; nephridial development ; epithelial innervation ; immunocytochemistry ; transporting epithelium ; Hirudo medicinalis
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract The formation of the definitive excretory system (nephridium and bladder complex) in Hirudo medicinalis during the last two thirds of embryonic development was observed with light- and electron microscopy, immunocytochemistry, and nuclear labeling. In jawed leeches, two excretory systems develop and function successively. The nephridia of the cryptolarva are associated with the larval sac and persist until the definitive nephridia are sufficiently developed to be functional. Development of the definitive excretory system begins with the differentiation of the (ectodermal) bladder and urethra. The cells from which they arise incorporate bacteria and are thereby recognizable at day 8. The (mesodermal) urine-forming tissues of the nephridium (canalicular cells and central canal cells) appear a day later. By day 17, the nephridia are in contact with the outlet region and structurally able to function. Each nephridium is individually innervated by a peripheral neuron, the nephridial nerve cell, which expresses FMR Famide-like immunoreactivity and begins growing into the nephridium on day 11. Organogenesis of the leech nephridium is compared with the formation of excretory organs in other species. The temporal correlation of innervation and the development of the transporting cells is discussed.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 2
    Digitale Medien
    Digitale Medien
    Springer
    Cell & tissue research 177 (1977), S. 195-214 
    ISSN: 1432-0878
    Schlagwort(e): Smooth muscle ; Connective tissue ; Echinoderms
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary An analysis of the ultrastructure of the tube feet of three species of sea urchins (Strongylocentrotus franciscanus, Arbacia lixula and Echinus esculentus) revealed that the smooth muscle, although known to be cholinoceptive, receives no motor innervation. The muscle fibers are attached to a double layer of circular and longitudinal connective tissue which surrounds the muscle layer and contains numerous bundles of collagen fibers. On its outside, the connective tissue cylinder is invested by a basal lamina of the outer epithelium to which numerous nerve terminals are attached. These are part of a nerve plexus which surrounds the connective tissue cylinder. The plexus itself is an extension of a longitudinal nerve that extends the whole length of the tube foot. It is composed of axons, but nerve cell bodies and synapses are conspicuously lacking, suggesting that the axons and terminals derive from cells of the radial nerve. Processes of the epithelial cells penetrate the nerve plexus and attach to the basal lamina. There is no evidence that the epithelial cells function as sensory cells. On the basis of supporting evidence it is suggested that the transmitter released by the nerve terminals diffuses to the muscle cells over a distance of several microns and in doing so affects the mechanical properties of the connective tissue.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 3
    Digitale Medien
    Digitale Medien
    Springer
    Cell & tissue research 254 (1988), S. 369-379 
    ISSN: 1432-0878
    Schlagwort(e): Hindgut efferents ; Synapses ; HRP labeling ; Orconectes limosus (Crustacea)
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary The distribution, morphology and synaptic connections of the hindgut efferent neurons in the last (sixth) abdominal ganglion of the crayfish, Orconectes limosus, have been investigated using light and electron microscopy in conjunction with retrograde cobalt/nickel and HRP labeling through the intestinal nerve. The hindgut efferent neurons occur singly and in clusters, and are unipolar. Their axonal projections are uniform and consist of a thick primary neurite with typical lateral projections and limited arborization of varicose fibers in the ganglionic neuropil. They also send lower order axon processes to the ganglionic neural sheath, where they arborize profusely, forming a network of varicose fibers. The majority of the efferent neurons project to the anterior part of the hindgut. HRP-labeled axon profiles are found in both pre- and postsynaptic position in the neuropil of the ganglion. HRP-labeled axon profiles also establish pre- and postsynaptic contacts in the intestinal nerve root. All hindgut efferent terminals contain similar synaptic vesicle populations: ovoid agranular vesicles (50–60 nm) and a few large granular vesicles (100–200 nm). It is suggested that the hindgut efferent neurons in the last abdominal ganglion are involved in: (1) innervation of the hindgut; (2) central integrative processes; (3) “en route” synaptic modification of efferent and afferent signals in the intestinal nerve; (4) neurohumoral modulation of peripheral physiological processes.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 4
    Digitale Medien
    Digitale Medien
    Springer
    Cell & tissue research 245 (1986), S. 397-404 
    ISSN: 1432-0878
    Schlagwort(e): Leech ; Nephridium ; Innervation ; Electron microscopy ; Cobalt filling ; Hirudo medicinalis
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary The main organs for salt and water homeostasis in the medicinal leech, the nephridia, were found to be densely innervated by a single branch of the corresponding median anterior segmental nerve. The projections of two different neurons into the nephridia are described: 1. Dendritic projections of the previously identified, afferent ‘nephridial nerve cell’, a possible salt receptor, lie between the urine forming cells and the blood vessels supplying the nephridium without making any contact. 2. Projections of an unidentified neuron which contains dense-core vesicles (85 nm) as well as smaller clear vesicles (45 nm) contact the primary urine forming canaliculus cells. The neurosecretory role of these neurons is considered.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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