Renal Integration Flashcards
what is the volume of the extracellular space determined by?
total body Na content
what determines the rate of Na excretion?
extracellular volume- sensed by volume sensors in the atria and other volume sensors
what maintains the ICF volume?
constant ECF osmolarity
what regulates the ECF osmolarity?
water intake and excretion (ADH)
what senses changes in osmolarity?
hypothalamus
what happens when osmolarity changes?
increase–>ADH is released and thirst is stimulated
how does body water affect urine outflow?
decrease–urine output can only decrease so much (0.5L)
increase- urine output increases linearly with water intake
what determines ADH release? how sensitive is it?
osmolarity changes- 1%
ECF volume changes- 5-10%
**more sensitive to osmolarity
what is the normal level of ADH?
in the middle, need somewhere to decrease from if water needs to be excreted
what happens to ADH sensitivity when the volume changes?
contraction- ADH sensitivity increases
expansion- ADH sensitivity decreases
what are the glomerular effects of ATII?
decrease RPF
increase filtration fraction
decrease GFR
what are the glomerular effects of sympathetic stimulation?
increase renal vascular resistance
decrease RPF and GFR
stimulates renin release
increase ATII production (via renin)
what are the glomerular effects of ANP?
vasodilates glomerular arteries
increases RPF and GFR
washes out medulla gradient, decreases water reabsorption
