Renal Physiology Flashcards
osmolarity
number of osmoles of solute per liter of solvent
temperature dependent
mosmol/L or mOsm/L
osmolality
number of osmoles of solute per kilogram of solvent
temperature independent
mosmol/kg or mOsm/kg
neural control
fast response
activated due to small changes in BP resulting from a change in blood volume
heart and lungs
endocrine control
slower response
activated if changes in BP persist
kidneys
hypertonic/concentrated urine
small volume and high osmolality
depends on concurrent multiplier system and ADH
hypotonic/diluted urine
large volume and low osmolality
thin descending loop of Henle
permeable to H2O
thick ascending loop of Henle
impermeable to H2O
countercurrent system
system of U-shaped tubules in which the flow of fluid is in the opposite direction in different limbs of the tubes allowing for passive transfers of molecules
countercurrent multiplier
loop of Henle
countercurrent exchanger
vasa recta
antidiuretic hormone (ADH)
controls H2O permeability of collecting ducts
determines final concentration of urine
helps body retain H2O
RAAS
increases sodium and water reabsorption
atrial natriuretic peptide (ANP)
increases sodium and water excretion
osmoreceptors
regulates ADH in response to high plasma osmolarity in a water deficit
hypothalamus
baroreceptors
regulates ADH in response to low blood volume and pressure in a water deficit
must be suppressed
cardiovascular
baroreceptors
regulates ADH in response to low blood volume and pressure in a water deficit
must be suppressed
cardiovascular
override osmoreceptors by acting as vasoconstrictors to regulate BP
thirst center
activated by hypothalamic osmoreceptors which are stimulated by ECF volume decrease and ECF osmolarity increase
renal clearance
Cn = Un/Pn x V
GFR
GFR = U x V / P
eGFR
(140-age) x w/Pcr x 72 (x0.85 for women)
prerenal AKI
caused by transient renal hypoperfusion
hypotension
decreased CO
decreased GFR
postrenal AKI
caused by obstruction of the urinary tract
enlarged prostate
kidney stones
bladder tumor
