A&P URINARY SYSTEM Instructor Terry Wiseth

2 Urinary Anatomy Kidney Ureter Bladder Urethra

3 Functions of Urinary System Clears blood of waste products of metabolism  Uremia  accumulation of toxic levels of wastes in blood maintain normal  H 2 O and electrolyte balance  fluid volumes  blood pressure  body pH

4 Kidneys Excretory Organ  Intestine, Skin, Lungs Excretes  N 2 wastes  Toxins  H 2 0  Electrolytes

5 Microscopic Structure Nephron  unit of function  1.25 million / kidney  Highly vascular  20% of blood pumped / min

6 Functions 1) maintain fluid balance 2) maintain electrolyte balance 3) maintain acid-base balance 4) remove N 2 wastes  urea 5) synthesize prostaglandin's 6) influence rate of secretion of hormones  ADH / Aldosterone

7 Kidney Failure blood constituents cannot be held in normal concentrations

8 Nephron Anatomy 1) Glomerulus 1) Glomerulus  Arterioles  Bowman’s Capsule 2) Tubule 2) Tubule  Proximal  Loop of Henle  Ascending  Descending  Distal  Collecting

9 Urine Formation Actions in forming urine  1) filtration  2) reabsorption  3) secretion

10 Glomerular Filtration blood flows through glomerular capillaries H 2 O and solutes filter out into Bowman’s Capsule

11 Glomerular Filtration blood flows through glomerular capillaries H 2 O and solutes filter out into Bowman’s Capsule

12 Glomerular Filtration pressure gradient causes filtration some kidney diseases  permeability of glomerulus increases  allows blood proteins to filter out into the capsule

13 Glomerular Filtration High blood pressure in the glomerulus forces small molecules from blood into the Bowman’s capsule

14 Glomerular Filtration TEM of filtration slits from capillaries in Bowman’s Capsule

15 Glomerular Filtration Stress can lead to constriction of afferent arterioles  causes filtration rate to lower  and renal suppression “kidney shutdown”

16 Glomerular Filtration glomerular filtration rate directly related to systemic blood pressure  ↓ BP = ↓ glomerular filtration  ↑ BP = ↑ glomerular filtration (slight)

17 Tubular Reabsorption movement of substances from tubular fluid out to blood  reabsorption from proximal convoluted tubules to blood

18 Tubular Reabsorption movement of substances from tubular fluid out to blood  reabsorption from proximal convoluted tubules to blood

19 Tubular Reabsorption Glucose, amino acids, ions and other useful substances are actively transported from the tubule into blood

20 Proximal Tubules Water follows passively by osmosis

21 Glucose Reabsorption if blood glucose levels exceed threshold amount (150mg/100ml)  not all glucose is reabsorbed

22 Renal Diabetes congenital sometimes maximum transfer capacity is reduced and excess glucose appears in urine even though blood glucose level is normal

23 Reabsorption from Loop of Henle Descending Loop  Water diffuses out of the tubule by osmosis

24 Reabsorption from Loop of Henle Ascending Loop  Salts are actively transported out of the tubule, but water cannot follow because the walls of the tubule are impermeable to water

25 Reabsorption from Loop of Henle NaCl is trapped in interstitial fluid of kidney medulla

26 Reabsorption from Distal Tubules proximal tubules reabsorb 2/3 of Na + distal tubules reabsorb 1/10 of Na +

27 Reabsorption from Distal Tubules distal tubules reabsorb H 2 O if antidiuretic hormone (ADH) is present

28 Distal Tubule K +, H + and other ions, and certain large molecules are actively transported from the blood into the tubule, regulating the pH and ionic concentration of the blood

29 Collecting Duct As the urine passes down the duct, water moves by osmosis from the duct into the blood

30 Collecting Duct As the urine passes down the duct, water moves by osmosis from the duct into the blood

31 ADH cause distal tubules to become permeable to H 2 O

32 ADH small concentrated volume of urine is excreted

33 ADH if no ADH in blood, then large volumes of urine produced (dilute concentration)

34 Regulation of Urine Volume 1) ADH 2) Aldosterone 3) Extracellular fluid volume 4) Urine solute concentration

35 Regulation of Urine Volume 1) ADH  Presence  decrease Urine Volume  Absence  increase Urine Volume

36 Regulation of Urine Volume 2) Aldosterone  increases Na + reabsorption in distal tubule with H 2 O following

37 Regulation of Urine Volume 3) urine volume relates directly to extracellular fluid volume (ECF)  ECF ↓ urine volume ↓  ECF ↑ urine volume ↑  rapid ingestion of large amount of fluid and resulting increased ECF leads to increased urinary output

38 Regulation of Urine Volume 4) high solute concentration in urine increases urine volume by osmotic pressure  untreated diabetes void large amounts of urine because excess glucose in blood “spilling over”

39 Influence of Kidney on Blood Pressure Renal Hypertension  decreased blood flow to kidney  constriction of arterioles  increased BP

40 Ureters Tubes leading from kidney to bladder  Urine moves by peristaltic movement

41 Ureters Renal Calculi  stones develop in kidney, washed out by urine into ureter distend ureter walls  pain

42 Bladder collapsible, elastic bag  Ureters  2  Bladder  Urethra  1

43 Functions of Bladder 1) reservoir for urine 2) expels urine distended causes sensation and desire to void

44 Urethra passageway for eliminating urine

45 Urethra passageway for eliminating urine

46 Urine H 2 O  95% N 2 wastes Electrolytes Toxins Pigments Hormones

47 Artificial Kidney Dialysis

48 Artificial Kidney Dialysis

49 Artificial Kidney continuous ambulatory peritoneal dialysis (CAPD)  dialysis fluid administered to peritoneal cavity

50 Kidney Transplant

END URINARY SYSTEM