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Renal Disease; Fluid and Electrolyte Disorders
Published in John S. Axford, Chris A. O'Callaghan, Medicine for Finals and Beyond, 2023
These are weak diuretics that inhibit the NCC cotransporter in the distal tubule, increasing urinary loss of sodium, chloride and water. As some sodium is exchanged in the collecting ducts for potassium, potassium loss also occurs.
The Loop of Henle and Production of Concentrated Urine
Published in Peter Kam, Ian Power, Michael J. Cousins, Philip J. Siddal, Principles of Physiology for the Anaesthetist, 2020
Peter Kam, Ian Power, Michael J. Cousins, Philip J. Siddal
During water excess, the fluid leaving the loop of Henle, osmolality 100 mOsm/kg H2O, is further diluted by the distal convoluted tubule, which is always impermeable to water while reabsorbing sodium and chloride. Similarly, the collecting ducts are relatively impermeable to water, and the fluid within them is unaffected by the high medullary interstitial fluid osmolality. The collecting ducts reabsorb more sodium and chloride so that large volumes of dilute urine are excreted.
The Pituitary Gland Eva Nagy
Published in Istvan Berczi, Pituitary Function and Immunity, 2019
Both oxytocin and vasopressin are octapeptides, synthesized by nerve cells located in the supraoptic and in the paraventricular nuclei of the hypothalamus and transported to the posterior pituitary where they are stored and released. Vasopressin plays an important regulatory role in water conservation and maintenance of body fluid osmolality, blood volume, and blood pressure. In healthy adults, plasma vasopressin concentration correlates with plasma osmolality. The average serum osmolality is 288 mOsm/kg. In this case the plasma vasopressin is around 1 pg/mℓ. Oxytocin is a regulator of lactation (milk ejection) and of uterine smooth muscle contraction. Oxytocin level of plasma in men and preovulatory women: 0.5 to 2 μ U/mℓ, ovulating women: 2 to 4 μ U/mℓ, lactating women: 5 to 10 μ U/mℓ. Increased plasma osmolality is a powerful stimulus for release of vasopressin. The hypertonic environment of the collecting ducts results in water reabsorption, tending to reduce plasma osmolality. Pathological deficiency of vasopressin results in an increased plasma osmolality and excretion of large volumes of pale, dilute urine with secondary polydipsia. This condition is called diabetes insipidus.
Effects of caffeic acid phenethyl ester use and inhibition of p42/44 MAP kinase signal pathway on caveolin 1 gene expression and antioxidant system in chronic renal failure model of rats
Published in Drug and Chemical Toxicology, 2023
Yilmaz Cigremis, Hasan Ozen, Merve Durhan, Selahattin Tunc, Evren Kose
Phospho-p42/44 MAPK immunoreactivity was observed only in the collecting ducts of renal tissue in the control group (Figure 4(a)). Comparably fewer collecting ducts with immunoreactivity were seen in the renal cortex than that of the medulla. Not all collecting ducts in medulla were also immunopositive for phospho-p42/44 MAPK and severity of the staining in epithelia showed differences in a given duct. Phospho-p42/44 MAPK immunoreactivity was mostly nuclear but some cytoplasmic staining was also seen. In general, no immunoreactivity was observed in glomerulia, proximal and distal tubules, however occasional proximal tubules showed some signs of immunopositivity. Compared to the control group, phospho-p42/p44 MAPK immunoreactivity was higher in the CsA group (p < 0.05) (Figure 4(b)). The number of immunostained ducts especially in the medulla and the density of immunostaining was higher in the CsA group. Immunostaining pattern in the renal cortex was however similar to that of the control group. In CsA + PD (Figure 4(c)), CsA + PD + CAPE (Figure 4(d)), and CsA + CAPE (Figure 4(e)) groups, phospho-p42/44 MAPK immunoreactivity pattern was similar to that of the control group (p > 0.05), though with slightly less immunoreactivity and fewer number of collecting ducts. CsA-V (Figure 4(f)), CAPE-V (Figure 4(g)) and PD-V (Figure 4(h)) groups also showed similar phospho-p42/44 MAPK immunoreactivity pattern to that of control group (p > 0.05).
Therapeutic role of Azadirachta indica leaves ethanolic extract against diabetic nephropathy in rats neonatally induced by streptozotocin
Published in Ultrastructural Pathology, 2021
Abd El-Fattah B. M. El-Beltagy, Amira M.B. Saleh, Amany Attaallah , Reham A. Gahnem
The renal sections from control (Figure 2A&A1) and neem supplemented (Figure 2B&B1) rats appeared with normal histological architecture whereas it is differentiated into outer cortex and inner medulla. The renal cortex displayed well-organized renal corpuscles and tubules. The renal corpuscle consists of glomerulus that is surrounded by Bowman’s space and intact Bowman’s capsule that lined with simple squamous epithelium. The renal tubules represented by proximal tubules (PT), distal tubules (DT) and collecting ducts (CD). The PT is characterized by its star-shaped lumen that is lined with brush bordered cubical epithelium. Moreover, the DT has relatively rounded lumen that lined by cubical epithelium with little microvilli. The CD lined with short cubical epithelium and has a relatively wider lumen than the PT and DT. The renal medulla displayed well-organized collecting ducts and Henel,s loops.
Connection of ES Cell-derived Collecting Ducts and Ureter-like Structures to Host Kidneys in Culture
Published in Organogenesis, 2021
The connection of one ureteric bud derivative to another is not a feature of natural UB/collecting duct ureter development. The entire ureter and collecting duct system develop by branching morphogenesis from the UB, with no need for any connections to be made and with no evidence of connections ever being made. Indeed, the branches of the growing tree show mutual repulsion.12 Within the kidney, however, nephrons are required to make a connection between their distal pole and the collecting duct branch that induced their formation in the first place.16 It may be that the need to perform this connection, the mechanisms of which are still not understood in detail, means that UB-derived epithelia retain an innate ability to make connections that generate open-lumen communications between the tubules involved.