Regulation of Body Fluid - Rao Flashcards
ECFV =
ECFV = ECF Na+ / PNa; since PNa is usually constant, mostly depends on ECF Na+
How is plasma Na kept constant?
AVP-mediated water excretion
What clinical sign is an indicator of reduced ECFV?
Orthostatic hypotension
Which heart sound is indicative of ECFV expansion?
S3 gallop (Casey)
What are some causes of edema with normal to low ECFV?
hypoalbuminemia (LIVER DISEASE)
burns
1 L of isoosmotic fluid retention raises body weight by how much?
1kg or 2.2 lbs
Thirst, ADH, and renal adaptations - which are fast and which are slow in terms of adapting to Na levels?
Thirst and ADH are fast (restore water balance in 1-2 hrs)
Renal adaptations are slow (2-4 days)
-results in temp sodium +/-
What are the three types/locations of receptors for regulating ECFV?
Neural stretch receptors in large veins that signal pituitary to lower AVP
Atrial stretch receptors that send para to vagus nerve to make AVP secretions; direct fires to kidney and cardio; secrete ANP
Arterial baroreceptors in arteries respond to high blood pressure to signal pituitary to secrete AVP
What are the stimuli for aldosterone release?
Plasma K high
Angiotensin
inhibited by Na
What is the mechanism of aldosterone?
Inc open ENaCs iN DCT/CD
Inc Na/Cl cotransporter
Inc synthesis of Na/K ATPase
Inc synthesis of Krebs cycle enzymes
ANP stimulant
Increased Plasma Na and atrial distention
ANP has the opposite actions of which other factor?
Aldosterone
What are the effects of ANP?
Inhibits Na reabsorption
Increases GFR and Na excretion
Inhibits aldosterone secretion by adrenals
Inhibits renin secretion
How does angiotensin II act on the PT?
Increases Na:H exchanger to increase sodium resorption by PT
How does ouabin-like factor work and where is it made?
Made in atrium
Strong Na/K ATPase inhibitor
