1. Kidney PracticalsDiuresis Dr. Mona Soliman, MBBS, MSc Department of Physiology College of Medicine 1426 H

2. Objectives • To measure the volumes and determine the composition of urine excreted by volunteers who have drunk: • No fluids (controls) • Water • Isotonic saline • Lasix • To be able to discuss the mechanisms by which the body excrete water and sodium

3. Experimental groups Controls Water Lasix Saline

4. Methods • Controls • Emptied their bladder at 10:00 am and discard the urine • At 12:00, 12:30, 1:00, 1:30 measured the volumes of urine the produce and provide sample for analysis

5. Methods…cont. • Water • Emptied their bladder at 10:00 am and discard the urine • At 12:00 drank one liter of water • At 12:00, 12:30, 1:00, 1:30 measured the volumes of urine they produce and provide sample for analysis

6. Methods…cont. • Saline • Emptied their bladder at 10:00 am and discard the urine • At 12:00 drank one liter of 0.9% saline • At 12:00, 12:30, 1:00, 1:30 measured the volumes of urine they produce and provide sample for analysis

7. Methods…cont. • Lasix • Emptied their bladder at 10:00 am and discard the urine • At 12:00 swallow lasix tablet (frusemide 40 mg) • At 12:00, 12:30, 1:00, 1:30 measured the volumes of urine they produce and provide sample for analysis

8. Urine analysis

9. Methods…cont. • Urine analysis for: • Volume, by a measuring cylinder • [Na+] and [K+] by flame photometry • Osmolality • pH

10. Calculations

11. Methods…cont. • Calculations • Flow rate (ml/min) = urine volume (ml)/ time (min) • Total Na excretion (mM)= [Na+] x urine volume (L) • Rate of Na excretion (M/min)= [Na] x flow rate (Divide by 1000 to convert ml to L)

12. Plot the Graph

13. Mechanisms???

14. Deprive of water  Plasma osmolality Stimulates osmoreceptors in hypothalamus  ADH secretion from posterior pituitary Water permeability in late distal tubule and CD  Water reabsorption  Urine osmolarity and  urine volume  Plasma osmolarity toward normal

15. Drink of water  Plasma osmolality Inhibit osmoreceptors in hypothalamus  ADH secretion from posterior pituitary Water permeability in late distal tubule and CD  Water reabsorption  Urine osmolarity and  urine volume  Plasma osmolarity toward normal

16. Isotonic Saline (0.9%) • Volume of ECF Osmolality same Stretch on right atrium (volume receptors in right atrium)  ANP (Atrial Natriuretic Peptide)  Na+ excretion by kidneys

17. ANP Actions • Blood flow to Kidneys (due to relaxation of Smooth muscles of blood Vessels) • GFR • Na+ loss in urine • Aldosterone • Na+ reabsorption in DCT (  Na+ loss in urine)

18. Lasix (Frusemide 40 mg) Act on thick ascending limb of loop of Henle and blocks the Na+-K+- 2Cl- Co-transport (loop diuretic) • Na+ excretion in urine • water excretion

20. GOOD LUCK