URINARY SYSTEM

• Urinary System


  Consists of: Two kidneys, Two ureters, One urinary bladder, One urethra
• Functions of kidneys


  • Regulation of ionic composition
  • Maintains blood osmolality
  • Regulates blood volume
  • Regulates blood pressure
  • Regulation of blood pH
  • Release of hormones
  • Regulation of blood glucose level
  • Excretion of wastes and foreign substances
• Ionic composition regulation


  Regulates blood levels of ions: sodium, potassium, calcium, chloride, phosphate
• Osmolality


  Measure of total number of dissolved particles per liter of a solution
• Regulates blood volume


  By conserving or eliminating water
• Regulates blood pressure


  By secreting the enzyme renin and by adjusting renal resistance encountered by blood flow through the kidneys
• Regulation of blood pH


  Conserves bicarbonate (important buffer of hydrogen ions)
• Release of hormones


  The kidneys release 1 hormone: Erythropoietin, which stimulates RBC production
• Regulation of blood glucose level


  The kidneys can deaminate the amino acid glutamate and use it for GLUCONEOGENESIS (synthesis of new glucose molecules) and release glucose into the blood
• Substances excreted by the kidneys


  • Ammonia
  • Urea
  • Bilirubin
  • Creatinine
  • Uric acid
  • Drugs and toxins
• Nephron


  Functional units of the kidneys that engage in 3 basic processes: Filtering blood, Returning useful substances to blood, Removing substances from the blood