When the kidneys fail

2. When the kidneys fail People with kidney failure (腎衰竭) must be treated immediately.

3. When the kidneys fail Otherwise, they may die quickly.

4. When the kidneys fail They can either undergo a kidney transplant (移植). transplanted kidney

5. When the kidneys fail They can either use a kidney machine (洗腎機).

6. When the kidneys fail They can either undergo peritoneal dialysis (腹膜透析). dialysis fluid in 4 hours later dialysis fluid out

7. When the kidneys fail They also have to make some changes in their diet.

8. When the kidneys fail e.g. avoid taking too much fluid and high-protein food.

9. 1 Why may a person die quickly if the kidneys fail to function

10. 2 How does a kidney machine treat kidney failure

11. 3 Why can’t people with kidney failure take in too much fluid and high-protein food

12. 1.1 Importance of regulating water content water intake water loss balanced

13. Water Balance in the Body • Figure 20-2

14. Water balance in a kangaroo rat (2 mL/day) Water balance in a human (2,500 mL/day) Ingested in food (750 mL) Ingested in food (0.2 mL) Ingested in liquid (1,500 mL) Water gain Derived from metabolism (1.8 mL) Derived from metabolism (250 mL) Feces (100 mL) Feces (0.09 mL) Urine (1,500 mL) Urine (0.45 mL) Water loss Evaporation (900 mL) Evaporation (1.46 mL) • Land animals manage water budgets by drinking and eating moist foods and using metabolic water

15. 1.1 Importance of regulating water content • if water intake  water loss  affects water content in blood  affects water potential of tissue fluid  water enters or leaves cells by osmosis  cells do not function properly or even die

16. 1.1 Importance of regulating water content control of the water content in the body osmoregulation (滲透調節) done by kidneys of urinary system (泌尿系統)

17. 1.1 Importance of regulating water content 1 keeps the water potential of the tissue fluid and hence the water potential of the cells stable, so that cells can function properly to sustain life. Osmoregulation

18. 1.1 Importance of regulating water content 2 The of the system are the major organs for osmoregulation. kidneys urinary

19. 1.2 The human urinary system (dorsal aorta) (posterior vena cava) (renal artery) (renal vein) female

20. 1.2 The human urinary system kidneys ureters urinary bladder female

21. 1.2 The human urinary system control urination sphincter muscles female

22. 1.2 The human urinary system male female urethra

23. 1.2 The human urinary system ureters urinary bladder (vas deferens) urethra male (penis)

24. 1.2 The human urinary system Video 1.1 Examination of the mammalian urinary system 1 Examine the urinary system of a dissected rat. 2 Identify the structures.

25. 1.2 The human urinary system Structure of the kidney 3D model cortex (皮質) medulla (髓) renal vein pelvis (腎盂) renal artery ureter

26. 1.2 The human urinary system Structure of the kidney

27. 1.2 The human urinary system Structure of the kidney cortex medulla

28. 1.2 The human urinary system Structure of the kidney branch from renal artery branch from renal vein

29. 1.2 The human urinary system Structure of the kidney nephron (腎元)

30. Key functions of most excretory systems: • Filtration: pressure-filtering of body fluids • Reabsorption: reclaiming valuable solutes • Secretion: adding toxins and other solutes from the body fluids to the filtrate Capillary Filtration Excretory tubule Filtrate Reabsorption Secretion Urine Excretion

31. 1.2 The human urinary system Structure of the kidney proximal convoluted tubule distal convoluted tubule Bowman’s capsule kidney tubule loope of Henle collecting duct

32. 1.2 The human urinary system Structure of the kidney proximal convoluted tubule distal convoluted tubule flow of urine Bowman’s capsule from another nephron loop of Henle collecting duct

33. 1.2 The human urinary system Structure of the kidney glomerulus Bowman’s capsule kidney tubule

34. Capillary Beds of the Nephron • Every nephron has two capillary beds • Glomerulus • Peritubular capillaries • Each glomerulus is: • Fed by an afferent arteriole • Drained by an efferent arteriole

35. 1.2 The human urinary system Blood supply of a nephron efferent arteriole glomerulus afferent arteriole Peritubular capillary branch from renal artery branch from renal vein

36. 1.2 The human urinary system 1.2 Examination of the mammalian kidney 1 Put a fresh pig’s kidney on a dissection tray. 2 Examine whether there are tubes coming from the kidney. Remove any fatty tissues and identify the tubes.

37. 1.2 The human urinary system 1.2 3 Cut the kidney longitudinally.

38. 1.2 The human urinary system 1.2 4 Identify various structures of the kidney. 5 Draw a labelled diagram of the longitudinal section of the kidney.

39. 1.2 The human urinary system 1 Kidneys Ureters

40. 1.2 The human urinary system 1 Urinary bladder Urethra

41. 1.2 The human urinary system 2 Structure of a nephron: a A nephron consists of the , the Bowman’s capsule , proximal convoluted tubule the distal convoluted tubule and the . collecting duct

42. 1.2 The human urinary system 2 Structure of a nephron: b The Bowman’s capsule encloses a network of capillaries called the glomerulus . The kidney tubule is surrounded by another network of capillaries which is continuous with the glomerulus.

43. 1.3 Functioning of a nephron • urine is formed by mainly two processes: ultrafiltration (超濾) reabsorption (重吸收)

44. 1.3 Functioning of a nephron • and: ultrafiltration reabsorption Active secretion

45. Mechanism of Urine Formation • Urine formation and adjustment of blood composition involve three major processes • Glomerular filtration • Tubular reabsorption • Active Secretion • Figure 24.9

46. 1.3 Functioning of a nephron 1 Ultrafiltration Bowman’s capsule • blood is under high hydrostatic pressure • capillary wall is differentially permeable • forces small molecules through the thin walls glomerulus

47. 1.3 Functioning of a nephron 1 Ultrafiltration urea salts glucose water amino acids

48. 1.3 Functioning of a nephron 1 Ultrafiltration • fluid filtered into the Bowman’s capsule: glomerular filtrate to proximal convoluted tubule

49. 1.3 Functioning of a nephron 1 Ultrafiltration • composition similar to plasma plasma proteins water  glucose amino acids salts urea to proximal convoluted tubule

50. Net Filtration Pressure (NFP) • The pressure responsible for filtrate formation • NFP equals the glomerular hydrostatic pressure (HPg) minus the osmotic pressure of glomerular blood (OPg) combined with the capsular hydrostatic pressure (HPc) NFP = HPg – (OPg + HPc)