Renal Lecture 1 Flashcards
what do the kidneys do?
regulate fluid volume, composition, osmolarity, ph, and excrete waste products and other things
where it water output controlled?
only at the kidneys
what is corrected osmolar activity?
osmolarity corrected for incomplete salt disassociation
what is osmotic pressure?
driving force for water, depends on solute concentration and reflection coefficient (ability to permeate membrane)
what affect does reflection coefficient have on osmotic pressure?
if it is low (unable to permeate membrane) then the pressure increases
where does water move (in terms of osmolarity?
from LOW to HIGH
what happens to hypotonic cells?
cell has higher osmolarity - cell swells
what happens to hypertonic cells?
cell has lower osmolarity - cell shrinks
how is urine formed (formula)
excretion = filtered + secreted + reabsorbed
where does glomerular filtration happen?
in bowman’s capsule
describe glomerular filtration?
blood moves from afferent arteriole by macula densa into modocytes then out through efferent arteriole
how does blood form urine?
goes through gomerular filtration barrier (filtrate moves through fenestrations, basement membrane, and slit pores in podocytes)
what is GFR?
glomerular filtration rate
how do you calculate GFR?
Kf (ultrafiltration coefficient) x Pnet (net filtration pressure
how do you calculate Pnet?
Pgc (favoured filtration) - Pbs (opposite filtration) - PI gc (pressure due to protein in cappilary)
what is the most influential pressure when calculating glomerular filtration?
Pgc
how does a constricted afferent arteriole impact pressures?
lowered Pgc, lowered GFR, lower RBF
how does a constricted efferent arteriole impact pressures?
increased Pgc, increased GFR, lower RBF
how does a dilated efferent arteriole impact pressures?
decreased Pgc, decreased GFR, increased RBF
how does a dilated afferent arteriole impact pressures?
increased Pgc, increased GFR, increased RBF
what causes a constricted afferent arteriole?
norepinephrine, epinephrine, dopamine, endothelin, high concentrations of angiotensin II
what causes a constricted efferent arteriole?
high concentration of angiotensin II, natruietic peptides (np)
what causes a dilated efferent artiole?
prostaglandins
what causes a dilated afferent arteriole?
Nitrous oxide (NO), bradykinin, prostaglandins, NPs
