Library

X
feed icon rss

Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
  • 1
    Electronic Resource
    Electronic Resource
    Osmo- und Volumenregulation beiHirudo medicinalis nach Nahrungsaufnahme (1973)
    Springer
    Journal of comparative physiology 84 (1973), S. 185-204 
    Details
    ISSN: 1432-1351
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Description / Table of Contents: Zusammenfassung 1. BeiHirudo medicinalis wurde die Änderung und Anpassung des Salz-Wasser-Haushaltes nach Aufnahme von Fütterblut und Salzlösungen untersucht. 2. Die Resorption hyperosmotischer Salzlösungen aus dem Magen führt zu einer Erhöhung der Osmolarität des Egelblutes auf 285 mOs/l und der Chloridkonzentration auf 86 mOs/l sowie zu einer Erhöhung des Volumens (= Wassergehaltes) des Egelkörpers. Sie ist weitgehend unabhängig von den osmotischen und ionalen Gradienten zwischen den Kompartimenten Magen und Egel. 3. Die Füllung des Magens mit Blut und anderen Salzlösungen führt zu einer Diurese. Als auslösender Faktor für diese Diurese wird eine Erhöhung des Volumens im Kompartiment Egel vorgeschlagen. 4. Während der Einstellung des Salz-Wasser-Haushaltes auf ein neues dynamisches Gleichgewicht ist der Harnfluß gesteigert (maximal 9fach); auch die Salzausscheidung durch die Nephridien und die Haut ist vergrößert. Dadurch wird in 12–24 Std das aus dem Magen resorbierte Flüssigkeitsvolumen aus dem Egel wieder ausgeschieden und die Volumenerhöhung im Kompartiment Egel kompensiert. Gleichzeitig wird die Steigerung der Osmolarität und Chloridkonzentration des Egelblutes kompensiert und der Mageninhalt in Osmolarität und Chloridkonzentration dem Egelblnt angeglichen.
    Notes: Summary 1. The salt and water balance of the leech was investigated after the uptake of blood and other electrolyte solutions into the stomach. 2. Resorption of hyperosmotic salt solutions from the stomach increase the osmolarity of the leech blood to 285 mOs/l, the chloride concentration to 86 mM/l, and the water content (= body volume) of the leech. 3. The uptake of blood and other salt solutions into the stomach causes diuresis. It is proposed that diuresis is induced by the increase in body volume of the leech. 4. During the adjustment of the salt and water balance to a new steady state the flow of urine is increased (to a maximum of 9-fold) and the salt excretion by the nephridia and the skin is also increased. By this mechanism within 12–24 hours the fluid volume absorbed from the stomach is eliminated and the increased body volume and increased osmolarity and chloride concentration of the leech blood are normalized. At the same time the osmolarity and chloride concentration of the stomach content are adapted to those of the leech blood.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00697606
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 2
    Electronic Resource
    Electronic Resource
    Organische Säurereste als wichtigste Anionen im Blut von Hirudo medicinalis (1970)
    Springer
    Journal of comparative physiology 70 (1970), S. 313-321 
    Details
    ISSN: 1432-1351
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Description / Table of Contents: Zusammenfassung Die Untersuchung der ionalen Zusammensetzung des Blutes von Hirudo ergab, daß Nitrat, Phosphat und Sulfat als Anionen mengenmäßig keine Rolle spielen. Dagegen konnte nachgewiesen werden, daß ein großer Teil der Anionen aus Citrat, Fumarat, Lactat und Succinat besteht. Die Proteinkonzentration im Blut von Hirudo beträgt 110 g/l.
    Notes: Summary The following anions were determined in the blood of the leech: nitrate, phosphate, sulfate, citrate, fumarate, lactate, and succinate. The inorganic anions are of negligible importance in cation binding. The sum of the organic anions and chloride balances approximately the sum of the cations. The protein concentration amounts to 110 g/l.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00297751
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 3
    Electronic Resource
    Electronic Resource
    Function and ultrastructure of the nephridium inHirudo medicinalis L. (1975)
    Springer
    Journal of comparative physiology 100 (1975), S. 307-315 
    Details
    ISSN: 1432-136X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary 1. The mechanism of urine formation in the nephridial excretory system ofHirudo medicinalis has been studied by measuring sodium and potassium concentrations in the primary urine (Na=85 meq/l; K=46 meq/l) and chloride and osmotic concentrations along the central canal. 2. A comparison of the Na/K ratio in blood (≈22), primary urine (≈2), and final urine (≈5) suggests that active potassium transport is one of the mechanisms of primary urine formation. 3. A decrease of osmotic and chloride concentrations along the central canal was found by micropuncture studies (Fig. 2). 94% or more of the solutes secreted in the primary urine are reabsorbed while water is excluded due to relatively low water permeability of the central canal cells. 4. If the nephridium is considered to be a system of 5 compartments (1=blood+connective tissue, 2=canaliculus cells, 3=canaliculus lumen, 4=central canal lumen, 5=central canal cells), two pathways of solute and water circulation can be envisaged (Fig. 3). It is suggested that low water permeability of the apical central canal cells is one factor controlling the flow rates of circulating solutes and water within the nephridial system. Furthermore, the functional consequences of the intimate contact between the canaliculus cells and central canal cells to the mechanisms of urine formation are discussed. 5. It is postulated that increased secretion of primary urine is a prerequisite for the increased diuresis after food uptake.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00691051
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 4
    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
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 5
    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
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 6
    Electronic Resource
    Electronic Resource
    Blood volume as a controlling factor for body water homeostasis inHirudo medicinalis (1978)
    Springer
    Journal of comparative physiology 127 (1978), S. 343-347 
    Details
    ISSN: 1432-136X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Raising the blood volume in leeches by blood transfusion from donor leeches resulted in temporarily increased urinary flow. Displacement of the blood within the leech by massage, produced temporarily increased urinary flow in segments with elevated blood volume and seemed to decrease urinary flow in segments with lowered blood volume. It is suggested that blood volume and body water homeostasis are controlled by a feed-back system.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00738419
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 7
    Electronic Resource
    Electronic Resource
    Effect of salt and volume loading on the circulation in the leech,Hirudo medicinalis L. (1988)
    Springer
    Journal of comparative physiology 158 (1988), S. 553-557 
    Details
    ISSN: 1432-136X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The effects of increased fluid volume in the closed vascular system on circulation were studied in the leech (Hirudo medicinalis) by intravascular pressure recordings and blood flow measurements. Significant increases in blood volume were achieved by crop loading with hyposmotic (72 mOsmol·kg−1 H2O) or hyperosmotic (300 mOsmol·kg−1 H2O) salt solutions or by infusion of isosmotic saline (200 mOsmol·kg−1) into the vascular system. During the high-pressure (HIP) phase, which maintains the rear-to-front circulation, systolic blood pressure in the heart was not affected. An increase in systolic pressure in the heart was observed during the low-pressure (LOP) phase, which supplies the segmental circulation. Heart rate was not changed by crop loading with hyposmotic saline or by vascular infusion. Heart rate decreased after crop loading with hyperosmotic saline. Blood flow rate in the dorsal vessel was increased by crop loading with hyposmotic saline, but not after crop loading with hyperosmotic saline. In all cases the diameter of the dorsal vessel was not affected. A possible mechanism controlling blood pressure and blood flow in the vascular system is discussed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00692563
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...