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1 2 People with kidney failure ( 腎衰竭 ) must be treated immediately.

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Presentation on theme: "1 2 People with kidney failure ( 腎衰竭 ) must be treated immediately."— Presentation transcript:

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3 2 People with kidney failure ( 腎衰竭 ) must be treated immediately.

4 3 Otherwise, they may die quickly.

5 4 They can either undergo a kidney transplant ( 移植 ). transplanted kidney

6 5 They can either use a kidney machine ( 洗腎機 ).

7 6 They can either undergo peritoneal dialysis ( 腹膜透析 ). dialysis fluid in dialysis fluid out 4 hours later

8 7 They also have to make some changes in their diet.

9 8 e.g. avoid taking too much fluid and high-protein food.

10 9 Why may a person die quickly if the kidneys fail to function 1

11 10 How does a kidney machine treat kidney failure 2

12 11 Why can’t people with kidney failure take in too much fluid and high-protein food 3

13 Importance of regulating water content water intake water loss balanced

14 13 Figure 20-2 Water Balance in the Body

15 14 Land animals manage water budgets by drinking and eating moist foods and using metabolic water Water balance in a kangaroo rat (2 mL/day) Water balance in a human (2,500 mL/day) Water gain Water loss Derived from metabolism (1.8 mL) Ingested in food (0.2 mL) Derived from metabolism (250 mL) Ingested in food (750 mL) Ingested in liquid (1,500 mL) Evaporation (900 mL) Feces (100 mL) Urine (1,500 mL) Evaporation (1.46 mL) Feces (0.09 mL) Urine (0.45 mL)

16 15 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 1.1 Importance of regulating water content

17 16 control of the water content in the body osmoregulation ( 滲透調節 ) done by kidneys of urinary system ( 泌尿系統 ) 1.1 Importance of regulating water content

18 17 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 1.1 Importance of regulating water content

19 18 2 The of the system are the major organs for osmoregulation. kidneys 1.1 Importance of regulating water content urinary

20 The human urinary system (dorsal aorta) female (posterior vena cava) (renal artery) (renal vein)

21 The human urinary system female kidneys ureters urinary bladder

22 The human urinary system female sphincter muscles control urination

23 The human urinary system female urethra male

24 The human urinary system male ureters urinary bladder (vas deferens) urethra (penis)

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

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

27 The human urinary system Structure of the kidney

28 The human urinary system Structure of the kidney cortex medulla

29 The human urinary system Structure of the kidney branch from renal artery branch from renal vein

30 The human urinary system Structure of the kidney nephron ( 腎元 )

31 30 Filtration Reabsorption Secretion Excretion Excretory tubule Capillary Filtrate Urine 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

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

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

34 The human urinary system Structure of the kidney glomerulus Bowman’s capsule kidney tubule

35 34 Capillary Beds of the Nephron has two capillary bedsEvery nephron has two capillary beds –Glomerulus –Peritubular capillaries Each glomerulus is: –Fed by an afferent arteriole –Drained by an efferent arteriole

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

37 Examination of the mammalian kidney The human urinary system 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.

38 The human urinary system 3 Cut the kidney longitudinally.

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

40 The human urinary system 1 Parts of urinary system Function Purify blood and form urine Carry urine from kidneys to urinary bladder Kidneys Ureters

41 The human urinary system 1 Parts of urinary system Function Stores urine temporarily Carries urine from urinary bladder to the outside Urinary bladder Urethra

42 41 a A nephron consists of the 2 Structure of a nephron: Bowman’s capsule 1.2 The human urinary system, the proximal convoluted tubule the, distal convoluted tubule and the. collecting duct

43 42 b The Bowman’s capsule encloses a network of capillaries called the 2 Structure of a nephron: glomerulus 1.2 The human urinary system. The kidney tubule is surrounded by another network of capillaries which is continuous with the glomerulus.

44 43 ultrafiltration ( 超濾 ) reabsorption ( 重吸收 ) 1.3 Functioning of a nephron urine is formed by mainly two processes:

45 44 Active secretion 1.3 Functioning of a nephron and: ultrafiltration reabsorption

46 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

47 46 1 Ultrafiltration blood is under high hydrostatic pressure 1.3 Functioning of a nephron glomerulus  forces small molecules through the thin walls Bowman’s capsule capillary wall is differentially permeable

48 47 1 Ultrafiltration 1.3 Functioning of a nephron glucose amino acids water salts urea

49 48 1 Ultrafiltration fluid filtered into the Bowman’s capsule: glomerular filtrate 1.3 Functioning of a nephron to proximal convoluted tubule

50 49 1 Ultrafiltration 1.3 Functioning of a nephron to proximal convoluted tubule water glucose amino acids salts urea plasma proteins  composition similar to plasma

51 50 Net Filtration Pressure (NFP) The pressure responsible for filtrate formation NFP equals the glomerular hydrostatic pressure (HP g ) minus the osmotic pressure of glomerular blood (OP g ) combined with the capsular hydrostatic pressure (HP c ) NFP = HP g – (OP g + HP c )

52 51 Glomerular Filtration Rate (GFR) Figure 24.10

53 52 2 Reabsorption absorption of useful substances and most of the water from the filtrate to the blood 1.3 Functioning of a nephron Your kidneys filter approximately 180L of plasma/day 99% of the filtrate gets reabsorbed, leaving L of urine per day Your kidneys filter approximately 180L of plasma/day 99% of the filtrate gets reabsorbed, leaving L of urine per day

54 53 2 Reabsorption 1.3 Functioning of a nephron from renal artery flow of urine to renal vein

55 54 Sodium Reabsorption: Primary Active Transport Tubule lumen with renal fluid

56 55 Glucose Reabsorption: Secondary Active Transport

57 56 Reabsorption: Both Primary and secondary Active Transport Sodium reabsorption is almost always by active transport –Na + enters the tubule cells from the lumen / filtrate –Na + is actively transported out of the tubules by a Na + - K + ATPase pump From there it moves to peritubular capillaries Na + reabsorption provides the energy and the means for reabsorbing most other solutes

58 57 Reabsorption by PCT Cells Figure 24.12

59 58 Reabsorption by PCT Cells Active pumping of Na + drives reabsorption of: –Water by osmosis –Anions by diffusion –Organic nutrients and selected ions by secondary active transport

60 59 Reabsorption by PCT Cells Figure 24.12

61 60 2 Reabsorption 1.3 Functioning of a nephron proximal convoluted tubuleblood glucose amino acids water salts amino acids

62 61 2 Reabsorption 1.3 Functioning of a nephron Substance reabsorbed Process Region where reabsorption occurs Glucose (100%) Amino acids (100%) Water (99%) Salts (80%) Urea (50%) Diffusion, active transport Osmosis Diffusion, active transport Diffusion At proximal convoluted tubule, loop of Henle, distal convoluted tubule & collecting duct At proximal convoluted tubule only

63 62 Figure 19-5 Filtration Fraction

64 63 2 Reabsorption 1.3 Functioning of a nephron kidney tubule is highly coiled to increase the surface area and the time for reabsorption

65 64 2 Reabsorption 1.3 Functioning of a nephron remaining glomerular filtrate in collecting duct is called urine mostly water with salts, urea and other metabolic waste

66 65 Essentially reabsorption in reverse, where substances move from peritubular capillaries or tubule cells into filtrate Tubular secretion is important for: –Eliminating undesirable substances such as urea and uric acid –Controlling blood pH 3. Secretion

67 Functioning of a nephron Proteins pass through the walls of the glomerulus and the Bowman’s capsule. 

68 Functioning of a nephron It is the amino acids that are filtered into the Bowman’s capsule and reabsorbed later.

69 68 1 In ultrafiltration, the high hydrostatic pressure 1.3 Functioning of a nephron glomerulus forces small molecules out of the blood into the Bowman’s capsule. inside the

70 69 The capillary wall of the glomerulus is 1 differentially permeable 1.3 Functioning of a nephron only allows small molecules to pass through. and

71 70 2 The composition of the glomerular filtrate is similar to that of plasma but it contains no. plasma proteins 1.3 Functioning of a nephron

72 Functioning of a nephron a All and 3 Reabsorption along the kidney tubule: glucose amino acids in the glomerular filtrate are reabsorbed into the blood by diffusion and active transport.

73 Functioning of a nephron b Most is reabsorbed by osmosis. 3 Reabsorption along the kidney tubule: water

74 Functioning of a nephron c Some are reabsorbed by diffusion and active transport. 3 Reabsorption along the kidney tubule: salts

75 Functioning of a nephron d Some is reabsorbed by diffusion and the rest is removed in the urine. 3 Reabsorption along the kidney tubule: urea

76 The role of the kidneys kidneys carry out osmoregulation by controlling the amount of water reabsorbed from the glomerular filtrate Osmoregulation

77 76 the amount of water reabsorbed is controlled by antidiuretic hormone (ADH) ( 抗利尿激素 ) 1.4 The role of the kidneys secretion of ADH is controlled by the hypothalamus ( 下丘腦 )

78 77 Diuresis Diuretics are a group of drugs given to help the body eliminate excess fluid through the kidneys. e.g. to treat hypertension, glaucoma, et Natural diuretic foods and drinks Melon Watercress Coffee Tea Coke (caffeinated soda)

79 The role of the kidneys hypothalamus has receptors to detect water content in blood controls secretion of ADH

80 The role of the kidneys pituitary gland secretes ADH ADH is transported by blood

81 80 under the action of ADH 1.4 The role of the kidneys  permeability of the wall of the collecting duct to water increases  a greater proportion of water is reabsorbed from the filtrate urine in different volumes and concentrations can be formed

82 81 Figure 20-4 Urine Concentration Osmolarity changes as filtrate flows through the nephron

83 82 Formation of Dilute Urine / hypotonic urine Filtrate is hypotonic after passing through the loop of Henle Dilute urine is created by allowing this filtrate to continue into the renal pelvis This will happen as long as antidiuretic hormone (ADH) is not being secreted Collecting ducts remain impermeable to water; no further water reabsorption occurs Diuresis – hypotonic urine (large volume of)

84 83 Figure 20-5b Water Reabsorption

85 84 Figure 20-5a Water Reabsorption Water movement in the collecting duct in the presence of vasopressin (ADH)

86 85 Formation of Concentrated / hypertonic Urine Antidiuretic hormone (ADH) inhibits diuresis In the presence of ADH, 99% of the water in filtrate is reabsorbed ADH is the signal to produce concentrated urine The kidneys’ ability to respond depends upon the high medullary osmotic gradient

87 86 The kidneys’ ability to make hypertonic urine depends upon the high medullary osmotic gradient Click the diagram to see an animation

88 The role of the kidneys receptors in hypothalamus water content increases normal water content in blood wall of collecting duct pituitary gland less ADH detected by less permeable smaller proportion of water reabsorbed larger volume of dilute urine

89 88 receptors in hypothalamus water content decreases normal water content in blood wall of collecting duct pituitary gland more ADH detected by more permeable smaller volume of concentrated urine greater proportion of water reabsorbed 1.4 The role of the kidneys

90 89 Filtrate H 2 O Salts (NaCl and others) HCO 3 – ; H + (control pH) Urea Glucose; amino acids Some drugs Key Active transport Passive transport INNER MEDULLA OUTER MEDULLA NaCl H 2 O CORTEX Descending limb of loop of Henle Proximal tubule NaCl Nutrients HCO 3 – H + K + NH 3 H 2 O Distal tubule NaCl HCO 3 – H + K + H 2 O Thick segment of ascending limb NaCl Thin segment of ascending limb Collecting duct Urea H 2 O

91 90 Figure 20-6 Water Reabsorption (reference) The mechanism of vasopressin action Collecting duct lumen Filtrate 300 mOsm H2OH2O Exocytosis of vesicles Cross-section of kidney tubule Collecting duct cell Second messenger signal H2OH2O cAMP Storage vesicles Aquaporin-2 water pores 600 mOsM H2OH2O Medullary interstitial fluid Vasopressin receptor 600 mOsM Vasa recta H2OH2O 700 mOsM Vasopressin binds to mem- brane receptor. Receptor activates cAMP second messenger system. Cell inserts AQP2 water pores into apical membrane. Water is absorbed by osmosis into the blood

92 91 Figure 20-6, step 1 Water Reabsorption (reference) Collecting duct lumen Filtrate 300 mOsm Cross-section of kidney tubule Collecting duct cell Medullary interstitial fluid Vasopressin receptor Vasa recta Vasopressin binds to mem- brane receptor mOsM 700 mOsM

93 92 Figure 20-6, steps 1–2 Collecting duct lumen Filtrate 300 mOsm Cross-section of kidney tubule Collecting duct cell Second messenger signal cAMP Medullary interstitial fluid Vasopressin receptor Vasa recta Vasopressin binds to mem- brane receptor. Receptor activates cAMP second messenger system mOsM 700 mOsM Water Reabsorption (reference)

94 93 Figure 20-6, steps 1–3 Collecting duct lumen Filtrate 300 mOsm Exocytosis of vesicles Cross-section of kidney tubule Collecting duct cell Second messenger signal cAMP Storage vesicles Aquaporin-2 water pores Medullary interstitial fluid Vasopressin receptor Vasa recta Vasopressin binds to mem- brane receptor. Receptor activates cAMP second messenger system. Cell inserts AQP2 water pores into apical membrane mOsM 700 mOsM Water Reabsorption (reference)

95 94 Figure 20-6, steps 1–4 Collecting duct lumen Filtrate 300 mOsm H2OH2O Exocytosis of vesicles Cross-section of kidney tubule Collecting duct cell Second messenger signal H2OH2O cAMP Storage vesicles Aquaporin-2 water pores 600 mOsM H2OH2O Medullary interstitial fluid Vasopressin receptor 600 mOsM Vasa recta H2OH2O 700 mOsM Vasopressin binds to mem- brane receptor. Receptor activates cAMP second messenger system. Cell inserts AQP2 water pores into apical membrane. Water is absorbed by osmosis into the blood Water Reabsorption (reference)

96 95 Figure 20-7 Factors Affecting Vasopressin Release

97 96 Figure 20-8 Water Balance The effect of plasma osmolarity on vasopressin secretion by the posterior pituitary

98 97 smaller amount of salts and greater proportion of water reabsorbed higher concentration of salts in blood smaller volume of urine with a high salt concentration formed (hypertonic urine) taking in excess salts 1.4 The role of the kidneys

99 98 Regulation of Kidney Function The osmolarity of the urine is regulated by nervous and hormonal control of water and salt reabsorption in the kidneys Antidiuretic hormone (ADH) increases water reabsorption in the distal tubules and collecting ducts of the kidney

100 99 Osmoreceptors in hypothalamus Hypothalamus ADH Pituitary gland Increased permeability Distal tubule Thirst Drinking reduces blood osmolarity to set point Collecting duct H 2 O reab- sorption helps prevent further osmolarity increase Homeostasis: Blood osmolarity STIMULUS The release of ADH is triggered when osmo- receptor cells in the hypothalamus detect an increase in the osmolarity of the blood

101 100 What’s the effect of the following on urine output : 1. a lot of water 2. a lot of salty foods 3. a large volume of salty solution. E.g seawater Assignment Assignment: 1.Explain why we cannot survive on seawater as drinking water. 2. Write an essay on how one can survive without drinking water while drifting on a raft in the open ocean (>300 words)

102 101 by forming urine Excretion 1.4 The role of the kidneys  to remove metabolic waste (e.g. urea)

103 102 by forming urine Excretion 1.4 The role of the kidneys  to remove metabolic waste (e.g. urea) constantly produced high concentration is toxic

104 103 Diuretics (reference) Chemicals that enhance the urinary output include: –Any substance not reabsorbed –Substances that exceed the ability of the renal tubules to reabsorb it Osmotic diuretics include: –High glucose levels – carries water out with the glucose –Alcohol – inhibits the release of ADH –Caffeine and most diuretic drugs – inhibit sodium ion reabsorption –Lasix – inhibits Na + -K + -2Cl  symporters

105 104 Physical Characteristics of Urine (reference) Color and transparency –Clear, pale to deep yellow (due to urobilin) -from the breakdown of hemeheme –Concentrated urine has a deeper yellow color –Drugs, vitamin supplements, and diet can change the color of urine –Cloudy urine may indicate infection of the urinary tract

106 105 Concentrated urine has a deeper yellow color

107 106 Physical Characteristics of Urine Odor / smell –Fresh urine is slightly aromatic –Standing urine develops an ammonia odor –Some drugs and vegetables (asparagus) alter the usual odor

108 107 Physical Characteristics of Urine pH –Slightly acidic (pH 6) with a range of 4.5 to 8.0 –Diet can alter pH Specific gravity –Ranges from to –Dependent on solute concentration

109 108 Chemical Characteristics of Urine Urine is 95% water and 5% solutes Nitrogenous wastes include urea, uric acid, and creatinine Other normal solutes include: –Sodium, potassium, phosphate, and sulfate ions –Calcium, magnesium, and bicarbonate ions Abnormally high concentrations of any urinary constituents may indicate pathology Disease states alter urine composition dramatically

110 109 Functions of the Kidneys Regulation of extracellular fluid volume and blood pressure Regulation of osmotic potential in blood Maintenance of ion balance Homeostatic regulation of pH Excretion of wastes

111 110 secretes less ADH pituitary gland 1.4 The role of the kidneys 1 Regulation of water content by negative feedback mechanism: normal water content in blood high water content in blood hypothalamus kidneys

112 The role of the kidneys In the kidneys: awall of collecting duct becomes permeable to water less ba proportion of water reabsorbed smaller ca volume of urine is formed larger dilute

113 112 secretes less ADH pituitary gland 1.4 The role of the kidneys 1 Regulation of water content by negative feedback mechanism: normal water content in blood high water content in blood hypothalamus kidneys water content in blood falls

114 113 secretes more ADH pituitary gland 1.4 The role of the kidneys 1 Regulation of water content by negative feedback mechanism: normal water content in blood low water content in blood hypothalamus kidneys

115 The role of the kidneys In the kidneys: awall of collecting duct becomes permeable to water more ba proportion of water reabsorbed greater ca volume of urine is formed smaller concentrated

116 115 secretes more ADH pituitary gland 1.4 The role of the kidneys 1 Regulation of water content by negative feedback mechanism: normal water content in blood low water content in blood hypothalamus kidneys water content in blood rises

117 116 2 After excess salts are taken into the body, the excess salts have to be excreted. A amount of salts and a proportion of water are reabsorbed. As a result, a smaller 1.4 The role of the kidneys greater small volume of urine with a high salt concentration is formed.

118 117 3 Excretion is necessary because metabolic waste is constantly produced and a high concentration of this waste is to the body. The kidneys form to remove metabolic waste (e.g. urea) from the blood. 1.4 The role of the kidneys toxic urine

119 The dialysis machine kidney machine Animation helps remove metabolic waste by haemodialysis ( 血液透析 )

120 The dialysis machine 1 blood with metabolic waste pump dialysis tubing fresh dialysis fluid

121 The dialysis machine dialysis tubing fresh dialysis fluid same concentration of solutes as normal plasma but has no metabolic waste

122 The dialysis machine dialysis tubing fresh dialysis fluid constant temperature bath dialysis fluid

123 The dialysis machine differentially permeable membrane of dialysis tubing

124 The dialysis machine 2 urea diffuses through the pores to the dialysis fluid

125 The dialysis machine 3 glucose is retained in blood (no net movement from blood to dialysis fluid

126 The dialysis machine 4 plasma proteins and blood cells are too large to pass through the pores

127 The dialysis machine 5 ‘cleaned’ blood used dialysis fluid (with urea)

128 The dialysis machine each treatment lasts for 4-6 hours three times a week costly

129 128 Peritoneal dialysis Peritoneal dialysis (PD) is a treatment for patients with severe chronic kidney disease. The process uses the patient's peritoneum in the abdomen as a membrane across which fluids and dissolved substances are exchanged from the blood.dialysiskidney diseaseperitoneumabdomenblood

130 129 Kidney transplant

131 130 1 A dialysis machine removes metabolic waste patient’s blood. from the 1.5 The dialysis machine

132 131 2 The dialysis fluid has the same concentration of solutes as normal plasma 1.5 The dialysis machine This allows metabolic waste to diffuse from the patient’s blood to the dialysis fluid while but no metabolic waste. glucose and other useful substances are retained in the blood.

133 132 Why may a person die quickly if the kidneys fail to function? 1 When the kidneys fail to function, the body cannot keep the water content in blood stable for cells to function properly.

134 133 Why may a person die quickly if the kidneys fail to function? 1 Besides, metabolic waste builds up in blood which can cause death.

135 134 How does a kidney machine treat kidney failure? 2 A kidney machine removes metabolic waste from the patient’s blood by haemodialysis.

136 135 Why can’t people with kidney failure take in too much fluid and high-protein food? 3 Excess proteins in the body are converted to urea by the liver.

137 136 3 The failed kidney cannot remove excess fluid and urea from the body. Why can’t people with kidney failure take in too much fluid and high-protein food?

138 137 3 Therefore, excessive intake of fluid and high-protein food must be avoided. Why can’t people with kidney failure take in too much fluid and high-protein food?

139 138 detected by is the maintenance of a stable Osmoregulation water content in blood hypothalamus urinary system done by kidneys main parts include

140 139 hypothalamus kidneys controls secretion of antidiuretic hormone functional units nephrons controls concentration and volume of form urine

141 140 by ultrafiltration kidneysurine reabsorption helps body remove fail to function can be treated by metabolic waste contains dialysis machine


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