Nephron

• Nephron Diagram

  A) Efferent arteriole

  B) Glomerulus

  C) Malpighian Body

  D) Afferent arteriole

  E) Bowman's capsule

  F) renal artery

  G) renal vein

  H) Loop of Henle

  I) Descending limb

  J) Ascending limb

  K) Distil convoluted tubule

  L) Proximal convoluted tubule

  M) collecting duct

  
• Nephron

  • Birth: kidneys have ~1 million microscopic nephrons (’renal tubules’)
  • Decreases with age
  • Osmoregulation + urine formation
  • Cortex + medulla tissue
  • Nephrons’ DCT opens to collecting duct
  • Several nephrons share
  • Join at kidneys’ pelvis
  • Empty urine to ureter
  • Renal artery
  • Oxygenated
  • Arterioles
  • Each nephron supply by afferent arteriole
  • To capillary network; glomerulus (capillary knot)
  • Bowman’s capsule
  • Blood drains to efferent arteriole (narrower lumen)
  • Then to capillary network around PCT, loop of Henle (Vasa recta), DCT + collecting duct
  • Drains to venules then renal vein
• Bowman’s Capsule (’renal capsule’)

  • Cup-shaped
  • Supports capillary network (glomerulus)
  • Cortex
  • Ultrafiltration (high pressure) of blood plasma occurs
  • Produces glomerular filtrate
  • Everything forced out
  • Except erythrocytes and leukocytes, platelets, and large plasma proteins
  • Too big for basement membrane
• Proximal convoluted tubule (PCT)

  • First coiled renal tubule part
  • Longest part
  • Cortex
  • Surrounded by capillary network branched from efferent arteriole
  • Single-cell cuboidal epithelium wall with brush border
  • Long microvilli project in tubule lumen
  • Many mitochondria; selective reabsorption needs ATP
  • Large SA
• Loop of Henlé

  • Descending limb and ascending limb
  • Walls permeabilities differ
  • Wider and narrower sections
  • Start in cortex, reach medulla
  • Surrounded by vasa recti capillaries
• Distal convoluted tubule (DCT)

  • Continuous with loop of Henlé’s ascending limb
  • Second coiled renal tubule
  • Cortex
  • Blood capillaries also surround
  • Joins collecting duct at most distal end