Glomerular FIltration Flashcards
the 2 basic renal processes:
filtration
reabsorption
secretion
how much blood to the kidneys receive (on average) per day?
What percentage is this of cardiac output?
1200mls/min
20-25%
none of the red cells and only a fraction of the plasma is filtered through the ……… ……….
the remainder passes via the ……… ………. into the …….. …………. then into the renal vein
bowmans capsule
efferent arterioles
peritubular capillaries
plasma constitutes ……..% of total BV
55
if plasma is 55% of BV and total BV to the kidney is 1200mls/min - what is the renal plasma flow?
660mls/min
GFR is usually what?
125ml/min
what is glomerular filtration dependent on?
starlings forces
what are the starling forces that must remain balances in glomerular filtration?
hydrostatic forces
oncotic forces
oncotic forces favour……..
reabsorption
hydrostatic forces favour……
filtration
why is the glomerular capillary pressure higher than in most other capillaries in the body?
the afferent arteriole is short and wide and offers little resistance to flow
(efferent arteriole is opposite - long and narrow)
‘golden rule of circulation’
if you have a high resistance - hydrostatic pressure upstream is ……….. while the pressure downstream is ………..
increased
decreased
at the glomerular capillaries - the hydrostatic pressure always exceeds the ……….. ……….
oncotic pressure
what is it that occurs at the glomerular capillaries?
and nothing else!
glomerular filtration
arterioles are subject to extrinsic control via
sympathetic VC nerves
circulating catecholamines
angiotensin II
