Physiology Urinary concentrating ability of kidney increases if there is: September 2008 A Increase in renal blood flow B Increase in GFR C Decrease in medullary hyperosmolarity D Contraction in extracellular fluid volume 💡 Explanation Urinary concentrating ability of kidney increases if there is: September 2008 ✓ Correct Answer: D. Contraction in extracellular fluid volume