Regulation of Body Fluids Flashcards
how much total body water does the ICF contain
2/3
how much total body water does the ECF contain
1.3
What are the subdivisions of the ECG
interstitial fluid
plasma volume
transcellular fluids
How much of the ECF is interstitial fluid
~75%
How much of the ECF is plasma volume
~25%
most important cation of ICF
K+
most important anions of ICF
phosphates, protein
most important cation of ECF
Na+
most important anion of ECF
Cl-
What happens if you ingest pure water
ECF becomes diluted and hyptonic
what happens if you add isotonic saline
ECF increases in size, osmolality stays the same
What happens if you add hypertonic salin
ECF osmolatity increases, volume of ECF comparment increases, volume of ICF compartment decreases
ineffective osmole
won’t cause fluid shifts because they can diffuse easily in and out of the membrane
why does elevated plasma urea conc not elict ADH release
because ADH release is triggered by an increase in osmolatity and urea does not cause an increase in osmolaity because it is an ineffective osmole
what causes thirst
shrinkage of thirst osmoreceptors in response to increased osmolaity of ECF. also a decrease in blood volume which is detected by barorecptors
how does angiotensin II affect thirst
increases thirst
what happens to bp if you give salt to a salt sensitive individual
increases
how does bp affect renal sympathetic nerves
increased bp causes decreased activity of renal sympathetic nerves
how does renal symphatetic nerves affect renin
decreases in renal sympathetic nerves causes decrease in renin secretion
how does renin secetion affect proximal tubule Na+ reabsorption
decrease in renin secretion causes decrease in prozimal tubule Na+ reabsorption
What takes place if you have a hemorrahges
decrease bp
increase activity of renal sympahteic nerves and renin secertion
increase plasma and renal renin, plasma and renal angiotesin ii
causes construction of renal arteriols
decreass RBF and GFR
decreas tubular sodium and water reaborption
decreass renal excretion of sodium and water
what are ADHs actions on the kidney
binds to basopressure type 2 receptors on colelcted sucks,
casoconstricts pericytes
increass permeability of medullary collecting ducts to urea
what happens when you vasoconstrict pericytes
decreass blood flow through the vasa recta
how does ADH increase permeability of medullary collecting ducts to urea
by increasing the number of urea uniporters
