Renal Physiology

• Nephrons


  Basic functional unit of kidneys

  
• Vertebrate excretory systems


  • Kidneys filter out waste from blood

  
• Romagnani et al. 2013: 'Renal progenitors: an evolutionary conserved strategy for kidney regeneration. Nature Reviews Nephrology 9: 137.'

  
• Nephrons


  • Similar across phyletic groups
  • Corpuscle, filtering unit
  • Proximal, intermediate & distal tubule
  • Excreting unit

  
• Glomerular ultrafiltration


  1. Capillary bed

  2. High pressures in glomerular capillaries within Bowman's capsule ↑ filtration

  3. Pressure modulated by juxtaglomerular apparatus (JGA)

  4. Cup-shaped structure

  5. Granular cells

  6. Macula densa

  
• Tubular reabsorption


  • Highly selective
  • Production of hyperosmotic urine

  
• Loop of Henle


  • Proportionally larger medullas produce more concentrated urine
• Body fluid composition


  90% ECF osmotic pressure from Na+ & Cl-
• Na+ load


  • Reflected by ECF volume
  • ECF hypertonic
  • ECF volume
  • Blood pressure

  
• Vasopressin


  Increases water reabsorption in the collecting duct