PLN 203 Lecture Notes - Lecture 11: Calcitriol, Antidiuretic, Ph
27 Apr 2017
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Document Summary
The goal of urine production: maintain homeostasis by regulating volume and composition of blood. Organic waste products: dissolved in bloodstream and are eliminated only while dissolved in urine, removal is accompanied by water loss. The kidneys: usually produce concentrated urine (four times plasma concentration) To concentrate filtrate by glomerular filtration: failure leads to fatal dehydration, absorb and retain valuable materials for use by other tissues (i. e. sugars and aa) Overview of renal functions: water and solute absorption, primarily along proximal convoluted tubules, active secretion, primarily at proximal and distal convoluted tubules. Long loops of juxtamedullary nephrons and collecting system: regulate final volume and solute concentration of urine. In some sites, (i. e. liver), pores are large plasma proteins can enter interstitial fluids: at renal corpuscle specialized membrane restricts all circulating proteins. Reabsorption and secretion: at kidneys, diffusions, osmosis, channel-mediated diffusion, carrier-mediated transport. If nutrient conc. rises in tubular fluid, reabsorption rates increase until carrier proteins are saturated.
