04 urinary tractkidney-2010 update


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04 urinary tractkidney-2010 update

  1. 2. Role of Kidney <ul><li>renal system – referring to the kidney </li></ul><ul><li>blood filtration </li></ul><ul><li>waste excretion </li></ul><ul><li>acid / base balance </li></ul><ul><li>blood pressure regulation </li></ul><ul><li>hormone secretion </li></ul>
  2. 3. Kidney Blood Flow <ul><li>Blood enters the kidney through the renal artery . </li></ul><ul><ul><li>renal arteries stem from the aorta </li></ul></ul><ul><li>Filtered blood exits the kidney through the renal vein . </li></ul><ul><ul><li>renal veins flow into the inferior vena cava </li></ul></ul>
  3. 4. Kidney Blood Flow
  4. 5. Blood and the Nephron <ul><li>Renal artery blood is filtered through nephrons . About a million nephrons make up the kidney. </li></ul><ul><li>Nephrons collect liquid to be excreted. </li></ul><ul><li>Fluids are exchanged between the nephron before blood is returned to renal vein. </li></ul>
  5. 6. Blood Flow <ul><li>The renal artery is split into afferent arterioles . </li></ul><ul><ul><li>blood brought to glomerulus; a capillary bed. </li></ul></ul><ul><ul><li>blood leaves through the efferent arterioles </li></ul></ul><ul><ul><ul><li>no veins involved </li></ul></ul></ul><ul><li>Efferent arterioles are the beginning of a network of peritubular capillaries , that wrap around the nephron. </li></ul>
  6. 9. Nephron <ul><li>Nephrons begin surrounding the glomerulus with the Bowman’s capsule structure. </li></ul><ul><ul><li>fluids to become urine flow to narrow proximal tubule </li></ul></ul><ul><ul><li>urine flows through loop of Henle </li></ul></ul><ul><ul><li>urine flows out of distal tubule </li></ul></ul><ul><li>Urine from multiple nephrons flow into the collecting duct. </li></ul>
  7. 11. Kidney Structure <ul><li>renal cortex – outside of kidney; location of Bowman’s capsule </li></ul><ul><li>renal medulla – middle of kidney; location of loop of Henle </li></ul><ul><li>renal pelvis – location of the ends of collecting ducts </li></ul>
  8. 12. Urine Flow <ul><li>Urine leaves the renal pelvis through the ureters and travels to the bladder . Fluid leaves the body through the urethra . </li></ul><ul><li>When ~200 mL of urine has collected in the bladder, the walls stretch and signals are sent to the brain. </li></ul><ul><li>At ~600 mL, urine will involuntarily be released. </li></ul>
  9. 14. Urinary Tract Infection (UTI) <ul><li>UTI’s are caused by bacterial growth in the urethra or bladder. </li></ul><ul><li>Symptoms: </li></ul><ul><li>frequent urination </li></ul><ul><li>sensation of needing to urinate (even is there is little to pass) </li></ul><ul><li>blood in urine </li></ul><ul><li>discharge in urine (cloudiness) </li></ul>
  10. 15. efferent artery afferent artery glomerulus Bowman’s capsule proximal tubule Loop of Henle distal tubule colluction duct
  11. 16. aorta inferior vena cava renal artery renal vein kidney ureter bladder urethra renal cortex renal medulla renal pelvis nephrons ureter
  12. 18. Three Functions of Urine Formation <ul><li>Filtration – movement of fluids from the glomerular blood to the Bowman’s capsule </li></ul><ul><li>Reabsorption – transfer of fluids from nephron into peritubular capillaries </li></ul><ul><li>Secretion – transfer of fluids from peritubular capillaries into nephron </li></ul>
  13. 19. Filtration <ul><li>Nutrients flow from glomerulus into Bowman’s capsule due to high blood pressure flow (65 mm Hg; normal ~ 25 mm Hg) </li></ul>
  14. 20. Nutrient Flow Solute Glomerulus  Bowman’s Capsule? water yes NaCl yes H + ions yes amino acids yes glucose yes plasma proteins no red blood cells (erythrocytes) no platelets no
  15. 21. Reabsorption <ul><li>Reabsorption saves us from having to continuously replenish our body with fluid. </li></ul><ul><li>20% of fluid flowing into kidney is filtered into kidney </li></ul><ul><li>less than 1% of nephron fluid is used to make urine </li></ul>
  16. 22. Reabsorption vs. Secretion <ul><li>Reabsorption </li></ul><ul><li>Secretion </li></ul><ul><li>protein transporters move nutrients into interstitial fluid and blood </li></ul><ul><li>kidney tissue will only reabsorb a certain level of nutrients – threshold level </li></ul><ul><li>protein transporters move wastes from blood to interstitial fluid to nephron </li></ul>
  17. 23. Renal System Videoclip <ul><li>http://www.youtube.com/watch?v=4-15JUVxAm8 </li></ul>
  18. 24. 1. Bowman’s Capsule <ul><li>water and dissolved solutes leave glomerulus; enter Bowman’s capsule </li></ul>water Na + H + Cl - glucose amino acids vitamins minerals urea uric acid
  19. 25. 2. Proximal Tubule <ul><li>selective reabsorption of nutrients (need transporters) </li></ul><ul><li>pH determined by HCO 3 - reabsorption and H + secretion </li></ul>H + NH 3 HCO 3 - , K + Na + , Cl - H 2 O amino acids glucose vitamins
  20. 26. 3. Loop of Henle – Descending Limb <ul><li>only permeable to H 2 O (osmosis) </li></ul><ul><li>impermeable to salt </li></ul><ul><li>fluids in tube are being concentrated </li></ul>H 2 O
  21. 27. 4. Loop of Henle – Ascending Limb <ul><li>only permeable to salt (need ionic transporters) </li></ul><ul><li>impermeable to water </li></ul>NaCl
  22. 28. 5. Distal Tubule <ul><li>selective reabsorption of nutrients (need transporters) </li></ul><ul><li>pH determined by HCO 3 - reabsorption and H + secretion </li></ul>H + NH 3 K + HCO 3 - Na + , Cl - H 2 O
  23. 29. 6. Collecting Duct <ul><li>urine formation by concentration nephron fluid </li></ul><ul><li>any urea and urine that is reabsorbed is less than that was filtered into nephron </li></ul>NaCl urea water
  24. 30. Videoclip <ul><li>http://www.youtube.com/watch?v=aQZaNXNroVY </li></ul>
  25. 32. Kidney Stones <ul><li>crystallization of some urine solutes </li></ul><ul><li>a 2 – 3 mm stone can obstruct flow to the ureter </li></ul><ul><li>Treatment: </li></ul><ul><ul><li>increased water consumption </li></ul></ul><ul><ul><li>surgery </li></ul></ul>