06 Renal Endocrine

Renin

  • JG (juxto glomerulus): modified smooth muscle cells of afferent arteriole. Sits between afferent/efferent, distal tubule and glomerulus
  • macula densa: DCT

  • macula densa: sense NaCl levels

  • Ang: made by liver, in blood
  • renin finds Ang, convert to AI

Ang II

  • increase Na/H2O
  • increase bicarb absorption in PCT
  • harder to get blood through whole system, thus lower RPF, FF goes up

Hydrostatic effect:

  • less fluid go to peritubular because of constriction
  • low hydrostatic pressure in peritubular capillaries
  • result: water drawn out

Oncotic effect:

  • protein stay in efferent, increase oncotic pressure
  • high oncotic pressure
  • fluid out

  • AII activate Na/H antiporter
  • Na absorption, H2O absorption
  • Contraction alkalosis: more H+ out to lumen, combine with bicarb to form water, absorption

Aldosterone

  • adrenal makes too much aldosterone

ANP

  • released by heart
  • opposite of renin
  • relax smooth muscle via cGMP to dilate afferent

PTH

  • low Ca most important
  • alcoholics very low Mg

  • increase Ca absorption in DCT

Vid D

  • D2 less active, not important

  • 25OH longest half life

  • renal failure: increase phosphate from unable to excrete
  • secondary hyper PTH from renal failure

EPO

  • peritubular interstitial cells
  • acts in bone marrow

  • association with increased mortality