Reabsorption and secretion of various substances in various quantity is taking place throughout the renal tubules. Minimal reabsorption in kidney occurs for which of the following?
Approximately 66% of filtered sodium ions (Na+), 85% of the NaHCO3, 65% of the K+, 60% of the water, and viually all of the filtered glucose and amino acids are reabsorbed in the proximal tubule. About half of filtered urea is reabsorbed in the proximal tubule. An amount equal to that reabsorbed is then secreted back into the loop of Henle. Finally, about half is reabsorbed again in the medullary collecting duct. The net result is that about half the filtered load is excreted. Ref: Eaton D.C., Pooler J.P. (2009). Chapter 5. Renal Handling of Organic Substances. In D.C. Eaton, J.P. Pooler (Eds), Vander's Renal Physiology, 7e.
Urea
Glucose
Na
HC03