Urinary System

• Structures of the excretory system

  • Renal Arteries
  • Kidneys
  • Ureter
  • Urethra
  • Renal Veins
• Pathway of the urinary tract

  1. Aorta carries oxygenated blood to the kidneys through the renal arteries

  2. Wastes and excess water are filtered from the blood by the kidneys, where they are then conducted through ureters to the bladder

  3. As the bladder begins to fill, receptors in the brain are activated. Eventually, urine will exit the body through the urethra

  4. Once blood is filtered by the kidneys, it returns to the heart through the renal veins
• Anatomy of the kidneys

  • Cortex
  • Medulla
  • Renal Pelvis
  • Afferent arteriole
  • Glomerulus
  • Efferent arteriole
  • Peritubular capillary
  • Bowman's capsule
  • Proximal tubule
  • Loop of Henle
  • Distal tubule
  • Collecting duct
• Urine Formation


  1. Filtration

  2. Reabsorption

  3. Secretion
• Filtration


  Movement of fluid from the blood into the Bowman's capsule
• Reabsorption


  Transfer of essential solutes and water from the nephron back into the blood
• Secretion


  Transport of materials from the blood into the nephron
• Reabsorption locations


  • Proximal convoluted tubules
  • Descending limb of Loop of Henle
  • Ascending limb of Loop of Henle
  • Distal convoluted tubules
  • Collecting ducts
• Substances reabsorbed


  • Water
  • Salt
  • Glucose
  • Potassium
  • Amino acids
  • Urea
  • NaCl
  • Potassium
  • Hydrogen ions
  • Hydrogen carbonate ions
  • NaCl
  • Urea
• Hormones


  • ADH
  • Aldosterone
• ADH


  Responsible for the direct reabsorption of water (when released ADH increases the permeability of the collecting ducts to H2O)
• Aldosterone


  Responsible for the reabsorption of salt (sodium makes distal tubule more permeable to NaCl)
• Symptoms associated with insufficient ADH production

  • Heart palpitations
  • Piss more
  • Kidneys excrete too much water
  • Increase in urination
  • Dehydration
  • Blood pressure decreases
• Secretion


  Movement of wastes from the blood into the proximal tubule, distal tubule, or collecting duct of a nephron
• Substances secreted


  • Ammonia
  • Excess H+ ions
  • Minerals
• pH control


  Secretion of excess hydrogen ions and restoration of bicarbonate ions in the blood
• Kidney Diseases


  • Diabetes mellitus
  • Diabetes insipidus
  • Nephritis
  • Kidney Stones
• Diabetes mellitus


  Inadequate secretion of insulin from cells in the pancreas, affects the kidneys
• Diabetes insipidus


  Defect in ADH hormone, absorbs too much water
• Nephritis


  Inflammation of Kidneys, some sort of urinary infection, bacteria entering the body through the urethra
• Kidney Stones


  Precipitation of mineral solutes from the blood, unbalanced diet
• Kidney Stones are pretty difficult to pee due to the blockage of the ureters, stones excreted in the urine
• Permeability


  A property of the distal tubule that allows sodium ions to be reabsorbed
• Aldosterone


  A hormone produced by the adrenal cortex responsible for regulating electrolyte and water balance