Fizjologia nerek i dróg
moczowych
Dariusz Nowak
Renal Functions—20% C.O.
1. Excretion of Waste Products
2. Fluid Balance
3. Regulation of Hemodynamics
4. Mineral metabolism
Stężenie moczu
Izoosmotyczny- stężenie równe
stężeniu osocza krwi
Stężony – stężenie > stężenia
osocza krwi
Rozcieńczony – mocz mniej
stężony niż osocze
Co jest prawidłowe ?
Spójrzmy na
nefron
Juxtaglomerular Apparatus
Renal Hemodynamics—Basic
Mechanism
Glomerular filtration rate(GFR)
=permeability(hydraulic-oncotic)
Renal Blood Flow(RBF)
Vasoconstriction—AngII and NO
GFR and RBF
Increased Afferent
arteriole resistance
Decreases both GFR
and RBF
Increasing Efferent
arteriole resistance
Increases GFR
decreases RBF
Regulation of GFR
Neural—Beta1 receptor
Tubuloglomerular Feedback
Hormones— e.g. AngII(E>A),
endothelin factor, vasopressin, ANP,
PTH, NO
Clinical Assessment of GFR
Inulin—Perfect, too expensive
Creatinine—overestimates
GFRsecreted
Urea—antidiuresis absorbed by
medullary collecting duct(30-40% of
GFR)
Renin-angiotensin-
aldosterone System
Sodium
ECF Volume
Potassium
Blood pressure
Renin-
Angiotensin
System
Countercurrent Exchange
Regulation of Potassium
98% intracellular
Kidney excretes 90% of dietary
intake
Secretion by distal nephron primary
mechanism.
70% reabsorbed by PCT, 90% by
distal nephron
Factors Regulating Potassium
Principal cells of CCT activated by
aldosterone.
11B hydroxysteroid dehydrogenase
tissue specific enzyme
Secretion is stimulated by alkalosis
Calcium
Most common divalent ion in body
Intestine, bone, and renal regulation
Filterable calcium increases with
acidemia
2% of daily intake secreted in urine