1. ELAINE N. MARIEB EIGHTH EDITION Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings PowerPoint ® Lecture Slide Presentation by Jerry L. Cook, Sam Houston University ESSENTIALS OF HUMAN ANATOMY & PHYSIOLOGY adapted by H. Goon May 2010 The Urinary System

2. Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings A) Functions of the Urinary System 1.Elimination of waste products (kidneys filter 200 liters of blood daily)  nitrogenous wastes (urea, uric acid)  toxins  drugs

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4. hemodialysis _____________________________________________________________________________________

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6. Peritoneal dialysis uses a natural filter inside your body—the lining of your belly, called the peritoneal membrane—to remove wastes and extra fluid from your body, and restore the normal balance of certain minerals in the blood (electrolytes). The dialysis fluid fills the belly and “pulls out” extra minerals and fluids from the bloodstream. These wastes then drain out of the body along with the dialysis fluid into a collection bag. Peritoneal dialysis is usually done at home.

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8. 2. Regulate aspects of homeostasis  Water balance  Electrolytes (ions: Na +, K +, Cl -, HCO3 - )  Acid-base (pH) balance in the blood

9. Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings B) Organs of the Urinary system Plus 1 2 3 4 5 6 7 8 9 10

10. Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings B) Organs of the Urinary system

11. Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings B) Organs of the Urinary system  Kidneys  Ureters  Urinary bladder  Urethra

12. Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Kidney Location and External Anatomy Figure 25.2a

13. Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings C) Kidneys 1. Location  against the dorsal body wall  at the level of T 12 to L 3  The right kidney is slightly lower than the left  an adrenal gland is above each kidney

14. Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings 2. Coverings of the Kidneys a) Renal capsule  fibrous covering on each kidney b) Adipose capsule  cushions and protects the kidney  keeps the kidney in its correct location

15. Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings 3. Regions of the Kidney a) Renal cortex – outer region b) Renal medulla – middle region c) Renal pelvis – inner collecting tube

16. Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings d) ureters, renal blood vessels, lymphatics, and nerves enter and exit at the hilum

17. Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings 4. Kidney Structures a) medullary/renal pyramids – triangular regions of tissue in the medulla b) renal columns – extensions of cortex-like material inward in between pyramids c) calyces – cup-shaped branches that funnel urine towards the renal pelvis

18. Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings 5. Blood Flow in the Kidneys Figure 15.2c ~ one-fourth (1200 ml) of systemic cardiac output flows through the kidneys each minute

19. Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Regions of the Kidney

20. Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings 6. Nephrons a) The structural and functional units of the kidneys [1 million per kidney] b) Responsible for forming urine c) Main structures of the nephron  renal corpuscle (glomerulus + glomerular capsule)  renal tubule

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22. d) glomerulus  a specialized capillary bed  continuous with arterioles at both ends (maintains high pressure)  afferent arteriole (large)  efferent arteriole (narrower) Figure 15.3c

23. Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings  Capillaries are covered with podocytes from the renal tubule  The glomerulus sits within a glomerular capsule (the first part of the renal tubule) Figure 15.3c

24. Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings e) renal tubule i.glomerular capsule (Bowman’s capsule) is a cup-shaped tubule that surrounds the glomerulus ii.Proximal convoluted tubule iii.Loop of Henle iv.Distal convoluted tubule Figure 15.3b

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27. 7. Blood Supply to Kidneys/Nephrons Figure 15.2c aorta renal artery (enters at hilus of kidney) segmental artery lobar artery

28. Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Figure 15.2c interlobar artery = in between renal pyramids arcuate artery = lateral branching of interlobar vessels at the boundary between the cortex and medulla interlobular artery = final branching of arcuate into afferent arterioles which enter the glomerulus

29. Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Blood flow to and from the kidney:

30. Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings 8. Types of Nephrons a) Cortical nephrons  Located entirely in the cortex of the kidney  85% of the nephrons

31. Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings b) Juxtamedullary nephrons  found at the boundary of the cortex and medulla  involved in the production of concentrated urine

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33. 9. Peritubular Capillaries  network of capillaries surrounding the renal tubule; formed by the branching of the efferent arteriole  normal, low pressure capillaries  attach to a venule  reabsorb (reclaim) some substances from renal tubule

34. Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings The kidneys remove 180 liters of filtrate from the blood per day. How much urine do you actually eliminate per day? ?????

35. Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings D) Urine Formation Processes glomerular filtration - tubular reabsorption + tubular secretion urine

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37. 1. Filtration  The fenestrated glomerular endothelium allows water and solutes (filtrate) to easily pass from the blood in the glomerulus into the glomerular capsule  Nonselective passive process  Water and solutes are forced through capillary walls b/c glomerular blood pressure is high, which causes a high net filtration pressure

38. Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Glomerular Filtration Rate (GFR) Figure 24.10

39. Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings  Plasma proteins are not filtered due to large size  GFR (glomerular filtration rate)= total amount of filtrate formed per minute by the kidneys [180L/day]

40. Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings 2. Tubular Reabsorption a) occurs as the peritubular capillaries reabsorb several materials [NOTE: back into bloodstream]  some water  glucose  amino acids  ions b) most reabsorption is via active transport, and occurs in the proximal convoluted tubule (PCT)

41. Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings c) materials NOT reabsorbed:  nitrogenous waste products  urea  uric acid  creatinine  excess water

42. Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings 3. Tubular Secretion – reabsorption in “reverse” Some materials move from the peritubular capillaries back into the filtrate (urine) forming in the renal tubules:  hydrogen and potassium ions  creatinine  drugs

43. Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Formation of Urine

44. Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings E) Hormonal control of urine formation 1.ADH (anti-diuretic hormone)  from pituitary gland  causes reabsorption of water (so urine contains less water) in DCT & collecting duct 2.aldosterone  from adrenal gland  causes Na+ reabsorption in DCT & collecting duct (e.g. water retention triggered by low blood volume or low blood pressure)

45. Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings ADH acts on the kidney to reabsorb water back into bloodstream (makes urine more concentrated) Alcohol inhibits the pituitary secretion of anti-diuretic hormone (ADH), which then causes ADH levels to drop. URINE  Therefore, the kidneys don't reabsorb as much water and the kidneys produce a higher volume of URINE (more diluted). e.g. Alcohol and urine production

46. Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings F) Characteristics of Urine for Medical Diagnosis  somewhat yellow color due to the pigment urochrome (from the destruction of hemoglobin) and solutes  sterile  slightly aromatic  normal pH ~ 6  specific gravity of 1.001 to 1.035

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48. G) Ureters  a pair of slender tubes that transport urine from the kidney to the bladder  Continuous with the renal pelvis  Enter the posterior aspect of the bladder  peristalsis aids gravity in urine transport

49. Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings H) Urinary bladder  muscular, hollow organ  stores up to 600 mL of urine (~ 2 cups)

50. Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings I ) Urethra  short tube that transports urine out of the bladder

51. Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings J) Micturition (urinary reflex)  stretch receptors are stimulated when the bladder fills with 150 mL, then 300 mL of urine; capacity of 600 mL  The muscles controlling micturition are controlled by the autonomic and somatic nervous systems.  During the storage phase the internal urethral sphincter remains tense and the detrusor muscle (in walls of the bladder) is relaxed.

52. Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings  During micturition, parasympathetic stimulation causes the detrusor muscle to contract and the internal urethral sphincter to relax.  The external urethral sphincter (skeletal muscle) is under somatic control and is consciously relaxed during micturition. e.g. potty training!

53. Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Review: Micturition = urination reflex (Fill in the blanks!)  at 300 mL, stretch receptors in the bladder wall are triggered  parasympathetic impulses trigger:  contraction of the detrusor muscle layer  relaxation of the internal urethral sphincter muscle  relaxation of the external urethral sphincter (skeletal muscle)

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55. ?? Regulation of Glomerular Filtration  Three mechanisms control the GFR  Renal autoregulation (intrinsic system)  Neural controls  The renin-angiotensin system (hormonal mechanism)