Question

question#60,61

d) Microvit : 59. In the space below, identify the structures (-e) in Figure 19.3 and indicate which figure illustrates the distal tubule and which illustrates the proximal tubule. a) Apical membrane figure b) : Jas Apical membrane b) leaky tight junction () Brush border I gj Tight" tight Junction e) mitochondria e) Mito Chondria Clinical Questions 60. Explain why a patient with sodium deficiency may also have glycosuria. ? 2 61. Helen has diabetes mellitus in which large amounts of glucose appear in the reabsorbed filtrate. What effect will this have on the volume of urine that she produces? Explain. CHAPTER 19 - The Urinary System: Renal Function 353

Answer 1

60. renal glycosuria may be caused by changes in a gene known as “SLC5A2” (also called the renal sodium-glucose cotransporter gene).SGLT2 is a member of the sodium glucose cotransporter family which are sodium-dependent glucose transport proteins. SGLT2 is the major cotransporter involved in glucose reabsorption in the kidney. Mutation in this gene results in excretion of glucose and sodium in the urine.

61. There is increased volume of urine in diabetes because of osmotic diuresis. when glucose levels are so high that glucose is excreted in the urine. Water follows the glucose concentration passively, leading to abnormally high urine output