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  • 1
    Electronic Resource
    Electronic Resource
    Organogenesis in the leech: development of nephridia, bladders and their innervation (1993)
    Springer
    Development genes and evolution 202 (1993), S. 329-340 
    Details
    ISSN: 1432-041X
    Keywords: organogenesis ; excretory organ ; nephridial development ; epithelial innervation ; immunocytochemistry ; transporting epithelium ; Hirudo medicinalis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: 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.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00188732
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  • 2
    Electronic Resource
    Electronic Resource
    A sensory neuron associated with the nephridia of the leechHirudo medicinalis L. (1983)
    Springer
    Journal of comparative physiology 152 (1983), S. 455-458 
    Details
    ISSN: 1432-1351
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary A peripheral neuron, lying on the urinary bladder, innervates the nephridia of the medicinal leech,Hirudo medicinalis. 1. Electrophysiological recording (extra-/intracellular) confirmed that it is an afferent neuron. 2. Intracellular injection with horseradish peroxidase shows that the cell soma sends processes into the ganglion of the particular body segment. 3. The possible function of the cell in controlling nephridial activity is discussed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00606435
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  • 3
    Electronic Resource
    Electronic Resource
    Water and salt excretion in the leech (Hirudo medicinalis L.) (1980)
    Springer
    Journal of comparative physiology 139 (1980), S. 97-102 
    Details
    ISSN: 1432-136X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary 1. The time courses of the osmotic and ionic concentrations in three different compartments (crop, blood and final urine) of the leech were measured after filling the crop with hypo- or hyperosmotic salt solution. Flow rates of the final urine were followed under the same conditions. 2. Volume regulation is accomplished within several hours but salt excretion takes longer. 3. No correlation was observed between the osmotic and ionic concentrations of blood and final urine. 4. The results indicate that the mechanisms controlling urine volume are independent of those controlling urine concentration. 5. A possible mechanism of fluid absorption from the crop is discussed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00691022
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  • 4
    Electronic Resource
    Electronic Resource
    Primary urine formation during diuresis in the leech,Hirudo medicinalis L. (1982)
    Springer
    Journal of comparative physiology 146 (1982), S. 75-79 
    Details
    ISSN: 1432-136X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The mechanisms underlying diuresis in the leech have been investigated. 1. The time course of the osmotic and ionic concentrations of the primary urine was measured after filling the crop with hypo- or hyperosmotic salt solutions. They were compared with data of blood and final urine, obtained earlier under the same conditions. 2. The strong diuresis after feeding is probably due to accelerating primary urine formation rather than to a decrease in reabsorption of primary urine volume. 3. The Na+ and K+ concentrations in the primary urine each show a distinct time course after hyper- or hypo-osmotic crop infusion. Cl− concentration always equals the sum of the Na+ and K+ concentrations. 4. Assuming that volume change between primary and final urine is negligible, it is calculated that primary urine secretion of Na+ is increased nearly 8 fold after hypo-osmotic crop infusion and 15 fold after hyperosmotic crop infusion, respectively, and secretion of K+ nearly 4 fold in both cases. Thus, during diuresis primary urine flow appears to be generated mainly by Na+-secretion. 5. The secretory rate of Na+, K+, and Cl− is not sensitive to the respective blood concentrations. 6. The percentage reabsorption of K+ is always higher than that of Na+. However, the percentage and real reabsorption of Na+ after hyperosmotic crop infusion is significantly lower than after hypo-osmotic crop infusion. 7. It is suggested that Na+ and K+ secretion and reabsorption are controlled by separate mechanisms.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00688719
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  • 5
    Electronic Resource
    Electronic Resource
    Nephridial innervation in the leech Hirudo medicinalis L. (1986)
    Springer
    Cell & tissue research 245 (1986), S. 397-404 
    Details
    ISSN: 1432-0878
    Keywords: Leech ; Nephridium ; Innervation ; Electron microscopy ; Cobalt filling ; Hirudo medicinalis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: 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.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00213947
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  • 6
    Electronic Resource
    Electronic Resource
    Structural and ultrastructural features of the inlet and outlet regions of the urinary bladders of the leech, Hirudo medicinalis L. (1989)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 201 (1989), S. 285-291 
    Details
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Each of the 34 nephridia in the leech, Hirudo medicinalis, has its own separate bladder. Urine flows from the last portion of the nephridium, the final canal, into the bladder through a special inlet which prevents backflow of urine. This inlet consists of a vestibule formed by two serially arranged septa, each with a small pore. As no muscles or cilia are associated with either the nephridia or the bladder inlet, urine flow into the bladder is passive. Urine leaves the bladder through an outlet that consists of a urethra with sphincters at both ends and an opening, the nephridiopore, in the ventral skin. The sphincter muscles are distinct from the body wall muscles and receive double innervation: urine retention and release is therefore active.
    Additional Material: 10 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jmor.1052010307
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