💧 Renal🟢 BasicRenal Physiology

Glomerular Filtration Rate (GFR)

The rate at which the kidneys filter fluid from the blood into the tubules, the best overall measure of kidney function.

Key points

Glomerular filtration is the first step of urine formation, in which fluid is pushed out of the glomerular capillaries into the tubule.
The glomerular filtration rate (GFR) is the volume filtered by both kidneys in a unit of time, and it is the best single measure of overall kidney function.
Filtration is driven by the blood pressure in the glomerular capillaries, opposed by the pressure in the capsule and by the pull of the plasma proteins.
The filtration barrier lets water and small molecules through but holds back the blood cells and large proteins, so normal filtrate is protein-free.
GFR is estimated in practice from the blood creatinine, and it falls as kidney function declines.

Memory trick

GFR is the volume filtered by both kidneys per unit time (the best measure of kidney function); driven by glomerular capillary pressure, opposed by capsule pressure and plasma-protein pull; the barrier holds back cells and big proteins; estimated from blood creatinine.

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💧 Renal🟢 BasicRenal Physiology

Glomerular Filtration Rate (GFR)

The rate at which the kidneys filter fluid from the blood into the tubules, the best overall measure of kidney function.

Key points

Glomerular filtration is the first step of urine formation, in which fluid is pushed out of the glomerular capillaries into the tubule.
The glomerular filtration rate (GFR) is the volume filtered by both kidneys in a unit of time, and it is the best single measure of overall kidney function.
Filtration is driven by the blood pressure in the glomerular capillaries, opposed by the pressure in the capsule and by the pull of the plasma proteins.
The filtration barrier lets water and small molecules through but holds back the blood cells and large proteins, so normal filtrate is protein-free.
GFR is estimated in practice from the blood creatinine, and it falls as kidney function declines.

Memory trick

All of Physiology More Renal