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Essentials of Anatomy & Physiology, 4th Edition Martini / Bartholomew PowerPoint ® Lecture Outlines prepared by Alan Magid, Duke University The Urinary.

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Presentation on theme: "Essentials of Anatomy & Physiology, 4th Edition Martini / Bartholomew PowerPoint ® Lecture Outlines prepared by Alan Magid, Duke University The Urinary."— Presentation transcript:

1 Essentials of Anatomy & Physiology, 4th Edition Martini / Bartholomew PowerPoint ® Lecture Outlines prepared by Alan Magid, Duke University The Urinary System The Urinary System 18 Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings Slides 1 to 91

2 Urinary System Organization Functions of the Urinary System Eliminate organic wastes Regulate plasma ion levels Regulate blood volume and blood pressure Adjust water loss Release cardiovascular hormones Stabilize blood pH Conserve nutrients Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings

3 Urinary System Organization Components of the Urinary System Kidneys Produce urine, a fluid made of water, ions, soluble compounds Ureters Urinary bladder Urethra During urination, conducts urine out of the body Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings

4 Urinary System Organization The Components of the Urinary System Figure 18-1

5 The Kidneys Anatomy of the Kidney Kidneys are retroperitoneal Left kidney superior to right Fibrous capsule surrounds the kidney Renal artery and renal nerve enter at hilum Renal vein and ureter exit at hilum Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings

6 The Kidneys An Overview of Kidney Anatomy Figure 18-2a

7 The Kidneys Figure 18-2(b) An Overview of Kidney Anatomy

8 The Kidneys Internal Anatomy of the Kidney Nephrons Urine produced by nephrons About a million nephrons per kidney Renal pelvis Urine collects here from calyces Input from two major calyces Each major calyx is fed by four to five minor calyces Urine leaves pelvis to ureter Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings

9 The Kidneys Figure 18-3(a) The Structure of the Kidney

10 The Kidneys Figure 18-3(b) The Structure of the Kidney

11 The Kidneys Figure 18-3(c) The Structure of the Kidney

12 The Kidneys Kidney Blood Supply Renal artery Interlobar arteries Arcuate arteries Interlobular arteries Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings

13 The Kidneys Kidney Blood Supply Nephron level Afferent arteriole Branch of interlobular artery Glomerulus Efferent arteriole Peritubular capillaries Vasa recta Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings

14 The Kidneys The Blood Supply to the Kidneys Figure 18-4(a)

15 The Kidneys The Blood Supply to the Kidneys Figure 18-4(b)

16 The Kidneys The Blood Supply to the Kidneys Figure 18-4(c)

17 The Kidneys The Blood Supply to the Kidneys Figure 18-4(d)

18 The Kidneys The Nephron Basic functional unit of the kidney Two parts to the nephron Renal corpuscle Renal tubule Feeds into collecting system Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings

19 The Kidneys Pathway of Urine through the Nephron First, filtered in the renal corpuscle Urine begins as filtrate Next, filtrate flows into renal tubule First, into the proximal convoluted tubule (PCT) Next, the loop of Henle Finally, the distal convoluted tubule (DCT) Last, exits to collecting duct Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings

20 The Kidneys Figure 18-5 A Representative Nephron and the Collecting System

21 The Kidneys Key Note The kidneys remove waste products from the blood; they also assist in the regulation of blood volume and blood pressure, ion levels, and blood pH. Nephrons are the primary functional units of the kidneys. Kidney Function: Urinary System Structure Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings PLAY

22 The Kidneys Functions of the Nephron Production of filtrate Glomerulus Reabsorption of nutrients PCT Reabsorption of water and ions DCT, collecting duct Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings

23 The Kidneys Parts of the Renal Corpuscle Glomerulus Knot of interconnected capillaries with a spherical shape Bowman’s capsule Encloses glomerulus with squamous epithelium Afferent arteriole Blood supply to glomerulus Efferent arteriole Blood drainage from glomerulus Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings

24 The Kidneys Figure 18-6(a) The Renal Corpuscle

25 The Kidneys Figure 18-6(b) The Renal Corpuscle

26 The Kidneys Glomerulus Anatomy Glomerular capillaries covered by podocytes Narrow slits separate foot processes of podocytes Capsular space surrounds glomerulus Filtrate accumulates here Bounded by Bowman’s capsule Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings

27 The Kidneys Proximal Convoluted Tubule Reabsorbs critical substances from filtrate Nutrients (e.g., glucose, amino acids) Ions Proteins Releases them into surrounding interstitial fluid Enter peritubular capillaries and return to blood stream Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings

28 The Kidneys Loop of Henle Descending limb Permeable to water Ascending limb Impermeable to water and solutes Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings

29 The Kidneys Distal Convoluted Tubule (DCT) Transport activities Actively secretes substances into urine Actively reabsorbs sodium from urine Juxtaglomerular apparatus Releases renin, erythropoietin Located at start of DCT Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings

30 The Kidneys Collecting Ducts Receive urine from nephrons Merge into papillary ducts Delivers urine to minor calyx Adjust final osmotic pressure of urine By reabsorbing water By transporting ions Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings

31 Principles of Urine Production Primary Purpose of Urine Production Excretion of dissolved solutes Metabolic wastes Urea Creatinine Uric acid Excess ions Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings

32 Principles of Urine Production Processes in Urine Formation Filtration Reabsorption Secretion Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings

33 Principles of Urine Production Filtration at the Glomerulus Blood pressure forces fluid and dissolved substances across the endothelial wall of glomerular capillaries into the capsular space Glomerular filtration rate (GFR) depends on blood pressure Any change in blood pressure affects filtration Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings

34 Principles of Urine Production Renin Release Decline in filtration pressure (blood pressure) triggers renin release Released by juxtaglomerular apparatus Renin leads to increased blood volume and blood pressure GFR returns toward normal Restores homeostasis Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings

35 Principles of Urine Production Key Note Roughly 180 liters of filtrate is produced at the glomeruli each day. That represents 70 times the total plasma volume. Almost all of that fluid volume must be reabsorbed to avoid fatal dehydration. Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings

36 Principles of Urine Production Tubular Reabsorption/Secretion PCT reabsorbs 60–70% of filtrate Nutrients Sodium, other ions Water Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings

37 Principles of Urine Production Tubular Reabsorption/Secretion (cont’d) Releases them into venous drainage for return to the blood stream Also, PCT secretes substances into tubular fluid Kidney Function: Urine Formation Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings PLAY

38 Principles of Urine Production Tubular Reabsorption/Secretion (cont’d) Loop of Henle Reclaims water, ions from filtrate Ascending limb pumps out sodium and chloride ions Descending limb absorbs water Interstitial osmotic pressure pulls water from tubular fluid Urea concentration rises as fluid is lost Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings

39 Principles of Urine Production Tubular Reabsorption/Secretion (cont’d) Distal Convoluted Tubule (DCT) Performs final adjustment Secretes or reabsorbs ions Reabsorbs sodium in exchange for secreted potassium and hydrogen ions Aldosterone increases sodium reabsorption and potassium loss Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings

40 Principles of Urine Production Control by Antidiuretic Hormone (ADH) Regulates water loss DCT, collecting tubule, collecting duct made permeable to water by ADH Water then exits to interstitial fluid and remains in the body Urine becomes concentrated (low in water, high in solute) The higher the ADH level, the more concentrated the urine Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings

41 Principles of Urine Production The Effects of ADH on the DCT and Collecting Duct Figure 18-7(a)

42 Principles of Urine Production Figure 18-7(b) The Effects of ADH on the DCT and Collecting Duct

43 Principles of Urine Production Water Balance in the Kidney More than 99% of water is reabsorbed from the filtrate by the renal tubules Water content of normal urine ranges from 93% to 97% Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings

44 Principles of Urine Production

45 Figure 18-8 A Summary of Kidney Function and Urine Formation

46 Principles of Urine Production Key Note Reabsorption depends on diffusion, osmosis, and active transport. The mechanism of water reabsorption is “water follows salt.” Many of these processes are regulated by local or hormonal mechanisms. Secretion is a selective, carrier-mediated process. Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings

47 Principles of Urine Production Vascular Control of Kidney Function Automatic regulation of filtration pressure by changes in diameter of afferent and efferent arterioles Autonomic regulation by sympathetic activation Powerful vasoconstriction of afferent arterioles Decreases GFR Also, redirects blood flow to other organs Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings

48 Principles of Urine Production Hormonal Control of Kidney Function Angiotensin II Aldosterone ADH Atrial natriuretic peptide (ANP) Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings

49 Principles of Urine Production Roles of the Renin-Angiotensin System in the Regulation of GFR Figure 18-9

50 Transport, Storage, & Excretion Transport and Storage of Urine Urine modification ends when fluid enters the renal pelvis Ureters, urinary bladder, urethra specialized for transport, storage, and excretion of urine Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings

51 Transport, Storage, & Excretion Ureters Ureters extend from renal pelvis to urinary bladder Smooth muscle in walls contract peristaltically Push urine toward bladder Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings

52 Transport, Storage, & Excretion Urinary Bladder Distensible muscular sac for urine storage Internal features include Trigone Neck Internal urethral sphincter Detrussor muscle Contraction forces urine into urethra Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings

53 Transport, Storage, & Excretion Figure 18-10(a) Organs for the Conduction and Storage of Urine

54 Transport, Storage, & Excretion Figure 18-10(b) Organs for the Conduction and Storage of Urine

55 Transport, Storage, & Excretion Organs for the Conduction and Storage of Urine Figure 18-10(c)

56 Transport, Storage, & Excretion The Urethra Longer in males than females External urethral sphincter formed by a circular band of skeletal muscle of pelvic floor Under voluntary control Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings

57 Transport, Storage, & Excretion Micturition Reflex and Urination Urination coordinated by micturition reflex Initiated by stretch receptors in the bladder wall Voluntary urination couples reflex with relaxation of external urinary sphincter Permits internal urinary sphincter to open Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings

58 Transport, Storage, & Excretion The Micturition Reflex Figure 18-11

59 Fluid, Electrolyte, & Acid-Base Homeostasis of Fluids Maintenance of normal volume and composition is crucial to life Three types of homestasis required Fluid balance Electrolyte balance Acid-base balance Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings

60 Fluid, Electrolyte, & Acid-Base Fluid and Electrolyte Balance Two fluid “compartments” Intracellular fluid (ICF) About 60% of total body water Extracellular fluid (ECF) About 40% of total body water Water moves freely within the ECF Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings

61 Fluid, Electrolyte, & Acid-Base Body Fluid Compartments Figure 18-12

62 Fluid, Electrolyte, & Acid-Base Figure Ions in Body Fluids

63 Fluid, Electrolyte, & Acid-Base

64 Water Balance Water intake normally equals water loss Water is gained from Eating Drinking Aerobic metabolism Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings

65 Fluid, Electrolyte, & Acid-Base Fluid Shift—Water movement between the ECF and the ICF Water moves to establish osmotic equilibrium Hypertonic ECF pulls water out of cells Hypotonic ECF push water into cells Causes cellular swelling Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings

66 Fluid, Electrolyte, & Acid-Base Electrolyte Balance Total electrolyte concentration affects water balance Individual concentrations affect a range of cellular functions Problems commonly result from a mismatch of sodium ion gain/loss Potassium ion imbalance can be dangerous or deadly Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings

67 Fluid, Electrolyte, & Acid-Base Sodium Ion Balance Sodium uptake from the gut parallels dietary intake Sodium loss occurs mainly in urine and sweat Sodium reabsorption along DCT stimulated by aldosterone Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings

68 Fluid, Electrolyte, & Acid-Base Potassium Ion Balance Concentration of K + in ECF normally very low Urinary excretion increases when sodium levels are low or when potassium levels are high Aldosterone stimulates potassium ion excretion Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings

69 Fluid, Electrolyte, & Acid-Base Key Note Fluid balance and electrolyte balance are interrelated. The impact of water gains or losses is reduced by fluid shifts between the ECF and ICF and by hormonal control of intake and excretion. Electrolyte gains or losses are opposed by fluid shifts, adjustments in ion absorption and secretion, and to water gain and loss. Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings

70 Fluid, Electrolyte, & Acid-Base Acid-Base Balance Normal pH of body fluids range from pH 7.35 to pH 7.45 pH > 7.45 is alkalosis (too alkaline) pH < 7.35 is acidosis (too acidic) Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings

71 Fluid, Electrolyte, & Acid-Base Carbonic Acid and pH Carbonic acid most important factor on pH CO 2 reacts with H 2 O to form carbonic acid Carbonic acid releases H + when it dissociates As CO 2 levels go up, pH goes down As CO 2 levels go down, pH goes up Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings

72 Fluid, Electrolyte, & Acid-Base The Basic Relationship Between Carbon Dioxide and Plasma pH Figure 18-14

73 Fluid, Electrolyte, & Acid-Base Metabolic Acids Acids produced by metabolism Lactic acid Produced by glycolysis Ketone bodies Produced in starvation (dieting), diabetes Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings

74 Fluid, Electrolyte, & Acid-Base Buffer Systems Resist changes in pH Consist of a weak acid and it anion dissociation product Three major buffer systems in the body Protein buffer system (in ECF and ICF) Carbonic acid-bicarbonate buffer system (in ECF) Phosphate buffer system (in ICF) Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings

75 Fluid, Electrolyte, & Acid-Base Protein Buffer Systems Amino acid subunits respond to H + changes Important proteins for buffering Plasma proteins Hemoglobin within RBCs Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings

76 Fluid, Electrolyte, & Acid-Base Carbonic Acid-Bicarbonate Buffer System Resists pH changes in ECF caused by metabolic (organic) acids Phosphate Buffer System Resists pH changes within cells Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings

77 Fluid, Electrolyte, & Acid-Base Compensations for pH Disturbances Respiratory compensation—Changes in ventilation lead to changes in pH by raising or lowering CO 2 levels Renal compensation—Kidney varies H + secretion and bicarbonate reabsorption depending on pH of ECF Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings

78 Fluid, Electrolyte, & Acid-Base Two Classes of Acid-Base Disorders Respiratory acid-base disorder—Caused by abnormal respiratory function leading to large changes in CO 2 levels Metabolic acid-base disorder—Caused by formation of organic acids or conditions which disturb the level of bicarbonate ion such as diarrhea or vomiting Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings

79 Fluid, Electrolyte, & Acid-Base Key Note The most common and acute acid-base disorder is respiratory acidosis, which develops when respiratory activity cannot keep pace with the rate of carbon dioxide generation in peripheral tissues. Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings

80 Aging and the Urinary System Age-Related Changes in Urinary System Loss of functional nephrons Reduced GFR Reduced response to ADH Urinary retention in men with prostate enlargement Drop in body water and mineral content Disorders of fluid, electrolyte, or acid-base balance Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings

81 The Urinary System in Perspective FIGURE Functional Relationships Between the Urinary System and Other Systems Figure of 11 Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings

82 Figure of 11 Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings Sweat glands assist in elimination of water and solutes, especially sodium and chloride ions; keratinized epidermis prevents excessive fluid loss through skin surface; epidermis produces vitamin D 3, important for the renal production of calcitriol The Integumentary System

83 Figure of 11 Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings The Skeletal System Axial skeleton provides some protection for kidneys and ureters; pelvis protects urinary bladder and proximal portion of urethra Conserves calcium and phosphate needed for bone growth

84 Figure of 11 Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings The Muscular System Sphincter controls urination by closing urethral opening; muscle layers of trunk provide some protection for urinary organs Removes waste products of protein metabolism; assists in regulation of calcium and phosphate concentrations

85 Figure of 11 Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings The Nervous System Adjusts renal blood pressure; monitors distension of urinary bladder and controls urination

86 Figure of 11 Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings The Endocrine System Aldosterone and ADH adjust rates of fluid and electrolyte reabsorption in kidneys Kidney cells release renin when local blood pressure declines and erythropoietin (EPO) when renal oxygen levels decline

87 Figure of 11 Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings The Cardiovascular System Delivers blood to capillaries, where filtration occurs; accepts fluids and solutes reabsorbed during urine production Releases renin to elevate blood pressure and erythropoietin to accelerate red blood cell production

88 Figure of 11 Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings The Lymphatic System Provides specific defenses against urinary tract infections Eliminates toxins and wastes generated by cellular activities; acid pH of urine provides nonspecific defense against urinary tract infections

89 Figure of 11 Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings The Respiratory System Assists in the regulation of pH by eliminating carbon dioxide Assists in the elimination of carbon dioxide; provides bicarbonate buffers that assist in pH regulation

90 Figure of 11 Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings The Digestive System Absorbs water needed to excrete wastes at kidneys; absorbs ions needed to maintain normal body fluid concentrations; liver removes bilirubin Excretes toxins absorbed by the digestive epithelium; excretes bilirubin and nitrogenous wastes produced by the liver; calcitrol production by kidneys aids calcium and phosphate absorption along digestive tract

91 Figure of 11 Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings The Reproductive System Accessory organ secretions may have antibacterial action that helps prevent urethral infections in males Urethra in males carries semen to the exterior


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