A Micropuncture Study of Kidney Function in the River Lamprey, Lampetra Fluviatilis, Adapted to Fresh Water
نویسنده
چکیده
Micropuncture techniques have been used to investigate the role of each nephron segment in the river lamprey. The proximal segment reabsorbed no more than 10% of filtered water and tubular fluid here was iso-osmotic to plasma, at about 250 m-osmol. Further water reabsorption occurred in later nephron segments so that 44% °f a u filtered water was reabsorbed. Dilution of tubular fluid began in the ascending limb of the nephron loop and continued in the distal and collecting segments, so that 96% and 97"5% °f filtered sodium and chloride, respectively, was reabsorbed by the kidney. Lampreys produce 337 ml kgday" of a dilute urine (31-2 m-osmol) and the urinary ducts appear not to modify the composition of this urine.
منابع مشابه
A micropuncture study of kidney function in the river lamprey Lampetra fluviatilis adapted to sea water.
Micropuncture techniques have been used to investigate kidney function in lampreys adapted to hyperosmotic media. Plasma electrolyte concentrations were maintained well below corresponding concentrations in the external environment. Urine composition was variable, but generally showed high concentrations of magnesium, sulphate and chloride ions. Lampreys in 50% sea water produced urine which wa...
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