What term describes the ability to maintain renal blood flow and glomerular filtration rate within narrow limits in the face of fluctuating MAP?
Considering the myogenic response, what happens to vascular resistance if blood pressure increases?
vascular resistance increases
*maintains constant flow
Describe afferent arteriolar response to change in tension (transmural pressure) and its effects on GFR and RPF.
stretch-activated cation channels
vascular smooth muscle contraction
increased afferent arteriolar resistance
decreased GFR, decreased RPF
Describe the signal of the tubulo-glomerular feedback mechanism.
macula densa detects flow rate (NaCl concentration in tubular fluid)
What is the action of the effector in the tubulo-glomerular feedback mechanism?
contraction of afferent arteriolar smooth muscle
Describe TGF in the case of increased GFR.
NKCC2 senses influx of Na, Cl
ATP released and converted to adenosine
adenosine binds receptor on afferent arteriole
contraction of afferent vascular smooth muscle
Why is renin inhibited by the tubulo-glomerular feedback in case of increased GFR?
renin would promote unwanted water retention
Describe TGF in the case of decreased GFR.
macula densa senses decreases in Na, Cl
NO stimulates prostaglandin production
prostaglandin binds to Gs on afferent arteriole
increased RPF, GFR, renin
How do glucocorticoids promote vasoconstriction?
potentiate vasoconstriction action of norepinephrine
Renal clearance ratio =
amount of substance in urine/concentration of substance in arterial plasma
Renal clearance =
(urine concentration of substance x urine flow)/arterial plasma concentration of substance
Derive the equation for GFR using inulin.
rate of inulin filtration = rate of inulin excretion
volume of plasma cleared = glomerular filtration rate
GFR = (urine concentration of inulin x urine flow)/renal plasma concentration of inulin