Urinary system anatomy and physiology


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Urinary system anatomy and physiology

  1. 1. Urinary System Anatomy and Physiology Part I
  2. 2. Urinary System <ul><li>Kidneys (2) </li></ul><ul><ul><li>Most important excretory organ </li></ul></ul><ul><ul><li>Eliminate waste </li></ul></ul><ul><li>Ureters (2) </li></ul><ul><li>Bladder (1) </li></ul><ul><li>Urethra (1) </li></ul><ul><li>Nephron Unit </li></ul><ul><ul><li>Functional unit of the kidney </li></ul></ul><ul><ul><li>Formation of urine </li></ul></ul><ul><ul><li>Tubular and vascular structures </li></ul></ul>
  3. 3. Kidney Location and Protection <ul><li>Kidneys are located in the posterior wall of the abdominal cavity </li></ul><ul><li>In the retroperitoneal space </li></ul><ul><li>Connective tissue (renal fascia) hold the kidneys in place </li></ul><ul><li>Adipose tissue cushion the kidneys </li></ul><ul><li>The lower rib cage partially enclose the kidney and protect them </li></ul>
  4. 4. Urinary System – Anterior/Posterior Views
  5. 6. Kidney Structures <ul><li>Kidney is reddish-brown </li></ul><ul><li>Looks like a bean </li></ul><ul><li>Approximately 4 inches x 2 inches </li></ul><ul><li>Hilus – indentation where blood vessels and structures enter or exit the kidney </li></ul><ul><li>Three Regions in the kidney if sliced in half – renal cortex, renal medulla, renal pelvis </li></ul>
  6. 7. Renal Cortex <ul><li>Light, outside region </li></ul><ul><li>Cortex means “bark” </li></ul>
  7. 8. Renal Medulla <ul><li>Dark, triangular structure </li></ul><ul><li>Form small cone shaped regions called renal pyramids </li></ul><ul><li>Each pyramid is separated by renal columns </li></ul><ul><li>The lower ends of the pyramids point to the renal pelvis </li></ul>
  8. 9. Renal pelvis <ul><li>A basin that collects the urine made by the kidney and helps form the upper end of the ureter </li></ul><ul><li>The edges of the renal pelvis closest to the renal pyramids are called calyces </li></ul><ul><li>Calyces collect the urine formed in the kidney </li></ul>
  9. 11. How do they work? <ul><li>Need a blood supply </li></ul><ul><li>Brought to the kidney via the renal artery </li></ul><ul><li>Renal artery stems from the abdominal aorta </li></ul><ul><li>20-25% of cardiac output goes to the kidneys </li></ul><ul><li>Smaller arteries supply blood to the nephron unit </li></ul><ul><li>Blood leaves the kidney via the renal veins </li></ul><ul><li>The renal veins empty into the inferior vena cava </li></ul>
  10. 13. Functions of the Kidneys <ul><li>Excrete nitrogenous waste from the body </li></ul><ul><ul><li>Urea </li></ul></ul><ul><ul><li>Ammonia </li></ul></ul><ul><ul><li>Creatinine </li></ul></ul><ul><li>Regulate blood volume </li></ul><ul><li>Help regulate electrolyte content of the blood </li></ul><ul><li>Regulate acid-base balance (pH) </li></ul><ul><li>Regulate blood pressure </li></ul><ul><li>Regulates red blood cell production </li></ul>
  11. 14. The Formation of Urine <ul><li>The Nephron Unit </li></ul><ul><li>Each kidney contains about 1 million nephron units </li></ul><ul><li>The number does not increase after birth </li></ul><ul><li>They cannot be replaced if damaged </li></ul><ul><li>2 parts </li></ul><ul><ul><li>Tubular component (renal tubule) </li></ul></ul><ul><ul><li>Vascular component </li></ul></ul>
  12. 15. Renal Tubules <ul><li>Glomerular capsule (Bowman’s Capsule) – “C” shaped capsule surrounding the glomerulus </li></ul><ul><li>Glomerulus – cluster of capillaries </li></ul><ul><ul><li>Proximal convoluted tubule </li></ul></ul><ul><ul><li>Loop of Henle – ascending and descending limb </li></ul></ul><ul><ul><li>Distal Convoluted tubule </li></ul></ul><ul><ul><li>Collecting duct </li></ul></ul>
  13. 16. Nephron
  14. 18. Renal Vasculature <ul><li>Receives blood from the renal artery </li></ul><ul><li>Renal artery branches into the afferent arterioles </li></ul><ul><li>Afferent arterioles feed into Bowman’s capsule </li></ul><ul><li>The efferent arterioles exit Bowman’s capsule </li></ul><ul><li>The efferent arterioles form the peritubular capillaries </li></ul><ul><li>The peritubular capillaries empty into the venules, large veins, and then into the renal veins </li></ul><ul><li>It is imperative you know the relationship between the tubular and vascular structures. </li></ul>
  15. 19. Urine Formation <ul><li>Formed in the nephron unit </li></ul><ul><li>Water and dissolved substances move through the renal tubules and vessels </li></ul><ul><li>Three processes are involved in urine formation </li></ul><ul><ul><li>Glomerular filtration </li></ul></ul><ul><ul><li>Tubular reabsorption </li></ul></ul><ul><ul><li>Tubular secretion </li></ul></ul>
  16. 20. Composition of Urine <ul><li>Sterile </li></ul><ul><li>95 % water </li></ul><ul><li>Nitrogen containing waste – urea, uric acid, ammonia, creatinine </li></ul><ul><li>Electrolytes </li></ul><ul><li>Light yellow color of urine is due to a pigment called urochrome </li></ul><ul><li>Urochrome is formed from the breakdown of hemoglobin in the liver </li></ul>
  17. 21. Urine Specific Gravity <ul><li>Ratio of the amount of solute to the total volume </li></ul><ul><li>Solute = substance dissolved in the urine </li></ul><ul><li>The greater the solute = greater the specific gravity </li></ul><ul><li>Concentrated Urine = high specific gravity </li></ul><ul><ul><li>Ex. dehydration </li></ul></ul><ul><li>Dilute Urine = low specific gravity </li></ul><ul><ul><li>Ex. Overhydration, diabetes insipidus </li></ul></ul>
  18. 22. Urine Characteristics <ul><li>Amount – 1500 ml in 24 hours </li></ul><ul><li>pH – average 6.0 </li></ul><ul><li>Specific Gravity – heavier than water (1.001-1.035) </li></ul><ul><li>Color – yellow (amber, straw colored, concentrated, orange, brown, red, sediment, clear or cloudy) </li></ul><ul><li>Dehydrated = deep yellow, dark </li></ul><ul><li>Overhydrated = pale yellow, colorless </li></ul>
  19. 23. Abnormal Constituents of Urine <ul><li>Albumin (protein) </li></ul><ul><li>Glucose </li></ul><ul><li>Red blood cells </li></ul><ul><li>Hemoglobin </li></ul><ul><li>White blood cells </li></ul><ul><li>Ketone bodies </li></ul><ul><li>Bilirubin </li></ul>
  20. 24. Urine Testing <ul><li>Urinalysis </li></ul><ul><li>Microscopic exam </li></ul><ul><li>Culture and sensitivity </li></ul><ul><li>Urine dipstick </li></ul><ul><li>Urine Drug and alcohol screening </li></ul><ul><li>24 hour urine testing </li></ul>
  21. 25. Your Plumbing – The Urinary Tract (Ureters, Urinary bladder, Urethra) <ul><li>Ureters </li></ul><ul><li>Transport urine, they do not alter it in any way </li></ul><ul><li>Urine moves in response to gravity and muscular movements called peristalsis through ureters. </li></ul>
  22. 26. Your “Plumbing”
  23. 27. The Bladder <ul><li>Stores urine temporarily until elimination </li></ul><ul><li>Located behind the symphasis pubis </li></ul><ul><li>A distended bladder or full bladder can be palpated above the syphasis in the abdominal cavity. </li></ul><ul><li>Bladder has 4 layers </li></ul><ul><ul><li>Mucous membrane </li></ul></ul><ul><ul><li>Submucosa </li></ul></ul><ul><ul><li>Detrusor muscle – involuntary smooth muscle </li></ul></ul><ul><ul><li>Serosa </li></ul></ul><ul><li>Contain rugae to allow for stretching </li></ul><ul><li>Trigone – triangular area in the floor of the bladder </li></ul>
  24. 29. Urination – “Micturition” <ul><li>Expelling urine from the bladder </li></ul><ul><li>The urge to urinate (void) happened at about 200 ml of urine in the bladder </li></ul><ul><li>At about 300 ml urine in the bladder, the urge becomes more uncomfortable </li></ul><ul><li>Moderately full = 500 ml urine </li></ul><ul><li>Overdistended bladder may have over 1000 ml urine </li></ul><ul><li>Bacteria in your bladder doubles every 4 hours. </li></ul><ul><li>Stimulated by stretch receptors </li></ul>
  25. 30. Urethra <ul><li>Carries urine from the bladder to the outside of the body </li></ul><ul><li>Internal sphincter prevents urine from emptying; composed of smooth muscle; involuntary </li></ul><ul><li>External sphincter at the upper portion of the urethra allows you to resist the urge to urinate; composed of skeletal muscle; voluntary </li></ul><ul><li>Female – short, opens to the outside at the urethral meatus </li></ul><ul><li>Male – longer, passes through the prostate gland; carries urine and sperm </li></ul>
  26. 32. Urinary Retention and Suppression <ul><li>Retention - Inability to void </li></ul><ul><ul><li>Post operative; anesthesia </li></ul></ul><ul><ul><li>Bladder dysfunction </li></ul></ul><ul><li>Suppression – no urine formation </li></ul><ul><ul><li>Kidney dysfunction </li></ul></ul>
  27. 33. Data Collection & Documentation <ul><li>Characteristics of urine </li></ul><ul><ul><li>Color </li></ul></ul><ul><ul><li>Sediment </li></ul></ul><ul><ul><li>Clear or cloudy </li></ul></ul><ul><ul><li>Odor </li></ul></ul><ul><li>How does the patient/resident void? </li></ul><ul><li>Urinary diversions? </li></ul><ul><li>Signs and symptoms </li></ul><ul><ul><li>Urgency </li></ul></ul><ul><ul><li>Frequency </li></ul></ul><ul><ul><li>Burning sensation </li></ul></ul><ul><ul><li>Hesitancy </li></ul></ul>
  28. 34. What is the Costovertebral Angle? Costovertebral Angle T12 T11 L1 12 th Rib R. Kidney L. Kidney Region to assess for kidney tenderness
  29. 35. Disorders of the Urinary System <ul><li>Glomerulonephritis </li></ul><ul><li>Polycystic Kidney </li></ul><ul><li>Pyelonephritis </li></ul><ul><li>Renal Calculi – kidney stones </li></ul><ul><li>Renal Failure </li></ul><ul><li>UTI – urinary tract infection </li></ul>
  30. 36. As We Age <ul><li>By age 80 there is a 50% reduction in nephron units; therefore a decreased ability to concentrate urine </li></ul><ul><li>Urinary bladder shrinks and becomes less able to contract and relax; therefore the elderly must void frequently </li></ul><ul><li>Bladder infection incidence increases </li></ul><ul><li>Increase in bladder incontinence due to weakened muscles </li></ul>