Urine production

• Filtration Pressure

  A) Efferent

  B) Afferent

  C) Glomerulus

  D) Bowman's capsule

  E) Net filtration

  F) 10

  G) Net filtration pressure

  H) 55

  I) 30

  J) 15

  K) 55

  L) 30

  M) 15

  N) 10

  O) hydrostatic pressure

  P) blood

  Q) Colloid

  R) osmotic

  S) gradient

  T) proteins

  U) fluid pressure

  V) fluid

  
• Filtrate from glomerular capillaries must cross 3 barriers before entering Bowman’s capsule

  A) Filtered Material

  B) Basal Lamina (basement membrane)

  C) Filtration slit

  D) Foot processes of podocytes

  E) Lumen

  F) Bowman's capsule

  G) Pores (or fenestration)

  H) endothelium

  I) Capillary lumen

  
• Glomerulus/Bowman’s Capsule Filter System 1

  A) Filtration slit

  B) minor

  C) podocytes

  D) Nucleus

  E) Major

  F) Minor

  G) foot

  H) podocyte

  I) Glomerular

  
• Glomerulus/Bowman’s Capsule Filter System 2

  A) Basement

  B) Capillary

  C) Secondary

  D) Primary

  E) Gaps

  F) secondary

  G) slit pores

  H) Nucleus

  I) podocytes

  J) Glomerular capillary

  K) Basement

  L) Primary processes

  M) podocyte

  N) Slit pore

  O) Lumen

  P) Bowman's capsule

  Q) Secondary processes

  R) podocyte

  S) Nucleus

  T) Endothelial

  U) Pore

  V) Lumen

  W) Capillary

  
• Urine Production

  • In each nephron
  • Urine: Filtered urea, some water, and some blood plasma salts
  • Ultrafiltration
  • High blood pressure in glomerulus
  • Afferent arteriole has wider diameter than efferent
  • Forces water + small solutes (any with relative molecular mass of <69,000) out blood
  • Filtrate crosses 3 barriers
  • Forms glomerular filtrate
  • Water, glucose, amino acids, urea + ions
  • Filtration pressure
  • High blood pressure forces glomerular filtrate into Bowman's capsule
  • Higher hydrostatic pressure than Bowman's capsule
  • Net pressure favors glomerular filtrate formation
• Glomerulus Filter System

  • 1st layer: Glomerular capillary wall
  • Single-cell endothelium
  • Above average pores/fenestrations between cells
  • Filtrate forced through by blood pressure
  • 2nd Layer: Basement membrane
  • Collagen fibres + glycoproteins
  • Underlies/supports endothelium
  • True filter
  • Determines molecules forced into Bowman’s capsule (<69,000 mass)
  • 3rd layer: Podocytes
  • Specialised epithelial cells
  • Form Bowman's capsule wall
  • Long finger-like membrane extensions
  • Primary and secondary processes
  • Slit pores between secondary processes