NURSING 3PA2 Lecture Notes - Lecture 14: Osmotic Concentration, Descending Limb Of Loop Of Henle, Countercurrent Multiplication
Document Summary
Role of fluid intake and output in fluid balance, electrolyte composition and neural control. Our fluid intake and loss changes dramatically on an hour to hour basis, thus the kidneys make adjustments to maintain solute concentration of the bodily fluids at about 300mosm (normal osmotic blood concentration of blood plasma. Maintaining this osmolarity is important for preventing cells from shrinking or swelling. The kidneys maintain the solute load of body fluids by regulating urine concentration and volume. When dehydrated, the kidneys produce a small volume of concentrated urine. When overhydrated, the kidneys produce a large volume of dilute urine. This means that fluid flows in opposite directions through adjacent segments of the same tube connected by a hairpin turn. It is these mechanisms that establish and maintain an osmotic gradient from the cortex to the medulla and it is aka the medullary osmotic gradient. This gradient allows the kidneys to vary urine concentration.
