1. Renal PhysiologyOverview Jeff Kaufhold, MD FACP

2. Renal Physiology • Structure • Clearance • Water Balance • Electrolytes • Acid-Base Balance • Hormonal Functions

3. Renal Anatomy • Renal Artery and Vein • Cortex – filtering Glomeruli • Medulla – Tubules, regulates water/ lytes • Ureters • Bladder • Urethra and Sphincter control

4. Anatomy of Urinary Tract

6. Glomerular Physiology • Filtration • Filtration membrane • Endothlial cell layer • Basement membrane • Epithelial cell layer • Electrical charge – negative • Clearance = waste product removal • Ultrafiltration = water removal

7. Filtration Membrane

10. Glomerular Blood Flow

11. Glomerular PhysiologyBlood flow determinants Systemic Efferent Afferent Filtration

12. Effect of Angiotensin on Glomerular Blood Flow

13. Glomerular PhysiologyBlood flow determinants Efferent Afferent PG's Local TGF Filtration

14. Glomerular PhysiologyBlood flow determinants Systemic Efferent Afferent PG's Local TGF Filtration

15. Glomerular filtration

16. Glomerular Physiology • Pathologic conditions: • Renal Artery Stenosis • Hypertension / Medication effects • Membrane problems • Lead to blood in urine – hematuria • -Loss of negative charge leads to protein in urine – proteinuria • -Diabetes, Glomerulonephritis

17. Blood Flow to Tubules

18. Renal Tubule PhysiologyOverview Prox. tubule Distal Tubule reabsorption Collecting duct Loop of Henle

19. Proximal Tubule • Function: Reabsorption • Features: • Brush border with cilia • Carbonic Anhydrase for reclaiming Bicarb • Filtration Fraction • Pathology: Renal tubular Acidosis

20. Renal Tubule PhysiologyOverview Prox. tubule Distal Tubule blood Tubule membrane reabsorption Collecting duct Ultrafiltrate Tubule lumen Loop of Henle Tubule membrane

21. Renal Tubule PhysiologyOverview Prox. tubule Distal Tubule Collecting duct Loop of Henle

22. Renal Tubule PhysiologyOverview Prox. tubule Distal Tubule Collecting duct impermeable to imperm. to H2O solute Loop of Henle

23. Renal Tubule PhysiologyOverview Prox. tubule Distal Tubule Collecting duct Loop of Henle

24. Renal Tubule PhysiologyOverview Ion Exchange Sodium for Potassium/Hydro Prox. tubule Distal Tubule Collecting duct Loop of Henle

25. Renal Tubule PhysiologyOverview Prox. tubule Distal Tubule Collecting duct Loop of Henle

26. Renal Tubule PhysiologyOverview Prox. tubule Distal Tubule Collecting duct ADH + permeable to H2O Loop of Henle ADH - impermeable

27. Function of Nephron Tubules

28. Renal Tubule PhysiologyOverview Prox. tubule Distal Tubule solute exchange reabsorption Collecting duct impermeable to imperm. to H2O solute ADH + permeable to H2O Loop of Henle ADH - impermeable

29. Interstitium • The tissue in between the tubules • Function: • Ammoniagenesis • Countercurrent multiplier • Pathology: • RTA, Loss of concentrating ability, AIN

30. Countercurrent Multiplier • Way to keep the concentrating ability of the kidney isolated from the rest of the body • Components: • Urine flow with sodium chloride pump • Blood flow from Vasa Recta • Pathology: • Sickle Cell /Trait, bladder obstruction

31. Countercurrent Multiplier

32. Countercurrent Multiplier

33. Countercurrent Multiplier WARM COLD

34. Renal PhysiologyEndocrine Functions • Renin – control of BP • Erythropoietin – turns on bone marrow to make red blood cells • Vitamin D activation – regulates bone metabolism, Calcium, Phosphorus and Parathyroid Gland.

35. Volume regulation • Active Sensors • Renal Autonomic nerves • Passive system • Like a system of lakes and spillways

36. Renal Structure C Artery P Vein M Ureter

37. Renal Structure Cortex U osmotic gradient 300 Vascular bundle Medulla collecting tubule Glomerulus U 1200

38. Renal PhysiologySensing of Volume • Effective Arterial Blood Volume (EABV) • Pathology: • Congestive Heart Failure • Cirrhosis • Pregnancy • Nephrotic Syndrome • Aldosteronoma

39. Pathologic States • CHF • Renal Artery Stenosis • Low Blood Flow

40. Pathologic States • Cirrhosis • Pregnancy • Nephrotic Syndrome Leaky capillaries

41. Pathologic States • Aldosteronoma • Tumor which • Produces too much • Aldosterone, causing • Fluid retention

42. Pathologic States • Aldosteronoma causes • Fluid retention • Hypertension • Perfusion of outer glomeruli sets upper limit on how much fluid can be retained.

43. Pathologic States • Removal of Aldosteronoma causes • Diuresis until volume is normal again, and • Hypertension improves

45. Why Kidney Patients willCome to Physical Therapists • Hip Fractures • Strokes • Heart attacks and heart surgery • Deconditioning • Neuropathy

46. Afferent. Art AT II constrict ACE-i dilate PG's NET dilate TGF NET constrict NSAID's constrict Aminophylline dilate Diltiazem dilate Filt Press maintained reduced increase parallels reduce increase reduced Glomerular Physiology Efferent Art. constrict dilate no effect no effect no effect no effect dilate