Control of ECF and Osmolality II Flashcards Preview

Renal Physio > Control of ECF and Osmolality II > Flashcards

Flashcards in Control of ECF and Osmolality II Deck (14):

Change in plasma osmolality (change in Na intake/output) cause or acute change in water intake or output

increase or decreased water reabsorption to correct osmolality


Changes in ECF volume and BP cause

excretion or reabsorption of Na


Main effectors of ECF volume

SNS, RAAS, ANP, ADH, pressure-naturiesis


High ECF volumes result in

increased GFR, decreased Na reabsorption, increased water excretion


Low ECF volumes

decreased GFR, increased Na reabsorption, and increased water retention


Edema is the accumulation of fluid in the interstitial space

Caused by the capillary filtrate coefficient, which increases when venous pressure increases (R side HF or liver disease)


If fluid is accumulating in the interstitium then the circulating volume decreases this is detected and

low volume senses would cause retention of Na and Water to increase circulating volume



is the most POWERFUL controller of ECF volume and long term BP, DIRECT effect of increased MAP and Na excretion


Pressure-naturiesis and chronic hypertension

the relationship is shifted to the right


Decreased TPR and stabilized, followed by increased MAP and TPR and BP what happened

Na excretion immediately went up with pressure, and Na excretion and H2O caused decreased ECF fluid and stabilized at low ECF volume


Alterations to pressure-naturiesis curve shift or slope

to a higher BP at same Na intake (chronic hypertension)


DASH diet (fruit and vegetables) decreases BP

shifts the pressure-naturiesis to the LEFT at a lower BP



hypertension, increased ECF volume, NORMAL Na excretion (NA balance) and not edemic


Continued aldosterone only retains Na and H2O to an extent and then intake = output, WHY?

pressure-natriuresis allows kidney to ESCAPE from high levels of aldosterone, if arterial pressure isn't recognized by the kidney the Na excretion will continue to respond to aldosterone