1. Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Excretion The removal of organic waste products from body fluids Elimination The discharge of waste products into the environment Homeostatic regulation of blood plasma Regulating blood volume and pressure Regulating plasma ion concentrations Stabilizing blood pH Conserving nutrients Functions of the urinary system

2. Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Figure 26.1 Figure 26.1 An introduction to the Urinary System

3. Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Figure 26.2 The Position of the Kidneys Figure 26.2a, b

4. Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Figure 26.3 Figure 26.3 The Urinary System in Gross Dissection

5. Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Superficial outer cortex and inner medulla The medulla consists of 6-18 renal pyramids The cortex is composed of roughly 1.25 million nephrons Major and minor calyces along with the pelvis drain urine to the ureters Sectional anatomy of the kidneys

6. Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Figure 26.4a, b Figure 26.4 The Structure of the Kidney

7. Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Figure 26.5 The Blood Supply to the Kidneys Figure 26.5c, d

8. Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Figure 26.5 The Blood Supply to the Kidneys Figure 26.5a, b

9. Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Figure 26.6 A Representative Nephron Figure 26.6

10. Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Production of filtrate Reabsorption of organic nutrients Reabsorption of water and ions Secretion of waste products into tubular fluid Nephron functions include:

11. Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Cortical nephrons ~85% of all nephrons Located in the cortex Juxtamedullary nephrons Closer to renal medulla Loops of Henle extend deep into renal pyramids Two types of nephron

12. Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Figure 26.7a Figure 26.7 Cortical and Juxtamedullary Nephrons

13. Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Figure 26.7b, c Figure 26.7 Cortical and Juxtamedullary Nephrons

14. Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Figure 26.8 The Renal Corpuscle Figure 26.8a, b

15. Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Figure 26.8 The Renal Corpuscle Figure 26.8c, d

16. Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Proximal convoluted tubule (PCT) Actively reabsorbs nutrients, plasma proteins and ions from filtrate Released into peritubular fluid Loop of Henle Descending limb Ascending limb Each limb has a thick and thin section Functional anatomy of the nephron Animation: Urinary System Anatomy PLAY

17. Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Distal convoluted tubule (DCT) Actively secretes ions, toxins, drugs Reabsorbs sodium ions from tubular fluid Functional anatomy of the nephron Animation: Urinary System Dissection and Flythrough PLAY

18. Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings SECTION 26-3 Principles of Renal Physiology

19. Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Regulating blood volume and composition Excreting waste products Urea Creatinine Uric acid Urine production maintains homeostasis

20. Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Filtration Blood pressure Water and solutes across glomerular capillaries Reabsorption The removal of water and solutes from the filtrate Secretion Transport of solutes from the peritubular fluid into the tubular fluid Basic processes of urine formation

21. Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Filtration in the kidneys modified by carrier mediated transport Facilitated diffusion Active transport Cotransport Countertransport Carrier proteins have a transport maximum (T m ) Determines renal threshold Carrier Mediated Transport

22. Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Accomplished via diffusion, osmosis, and carrier- mediated transport T m determines renal threshold for reabsorption of substances in tubular fluid Reabsorption and secretion

23. Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Figure 26.9 An Overview of Urine Formation Figure 26.9

24. Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Figure 26.10 Glomerular Filtration Figure 26.10

25. Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Figure 26.10 Glomerular Filtration Figure 26.10a, b

26. Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Amount of filtrate produced in the kidneys each minute Factors that alter filtration pressure change GFR Glomerular filtration rate (GFR)

27. Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings A drop in filtration pressure stimulates Juxtaglomerular apparatus (JGA) Releases renin and erythropoietin Factors controlling the GFR

28. Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Figure 26.11a Figure 26.11 The Response to a Reduction in the GFR

29. Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Figure 26.11b Figure 26.11 The Response to a Reduction in the GFR

30. Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Produces powerful vasoconstriction of afferent arterioles Decreases GFR and slows production of filtrate Changes the regional pattern of blood flow Alters GFR Stimulates release of renin by JGA Sympathetic activation

31. Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Glomerular filtration produces fluid similar to plasma without proteins The PCT reabsorbs 60-70% of the filtrate produced Reabsorption of most organic nutrients Active and passive reabsorption of sodium and other ions Reabsorption of water Secretion also occurs in the PCT Reabsorption and secretion at the PCT Animation: Early Filtrate Processing PLAY Animation: Glomerular filtration PLAY

32. Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Figure 26.12 Transport Activities at the PCT Animation: Proximal Convoluted Tubule PLAY Figure 26.12

33. Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings The loop of Henle and countercurrent multiplication Countercurrent multiplication Between ascending and descending limbs of loop Creates osmotic gradient in medulla Facilitates reabsorption of water and solutes before the DCT Permits passive reabsorption of water from tubular fluid

34. Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Figure 26.13a Figure 26.13 Countercurrent Multiplication and Concentration of Urine

35. Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Figure 26.13b Figure 26.13 Countercurrent Multiplication and Concentration of Urine

36. Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Figure 26.13c Figure 26.13 Countercurrent Multiplication and Concentration of Urine

37. Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings DCT performs final adjustment of urine Active secretion or absorption Absorption Tubular cells actively resorb Na + and Cl - In exchange for potassium or hydrogen ions (secreted) Reabsorption and secretion at the DCT

38. Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Figure 26.14 Figure 26.14 Tubular Secretion and Solute Reabsorption at the DCT Animation: Distal Convoluted Tubule PLAY

39. Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Figure 26.14c Figure 26.14 Tubular Secretion and Solute Reabsorption at the DCT

40. Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Reabsorption and secretion along the collecting system Water and solute loss is regulated by aldosterone and ADH Reabsorption Sodium ion, bicarbonate, and urea are resorbed Secretion pH is controlled by secretion of hydrogen or bicarbonate ions

41. Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Control of urine volume and osmotic concentration Urine volume and osmotic concentration are regulated by controlling water reabsorption Precise control allowed via facultative water reabsorption

42. Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Figure 26.15 Figure 26.15 The Effects of ADH on the DCT and Collecting Ducts

43. Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Figure 26.15a, b Figure 26.15 The Effects of ADH on the DCT and Collecting Ducts

44. Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Removes solutes and water Balances solute reabsorption and osmosis in the medulla Function of the vasa recta

45. Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Figure 26.16 A Summary of Renal Function Figure 26.16a