00:01
The glomerular filtration rate
is the volume of filtrate form
permanent by both kidneys.
00:08
This is normally about a 120
to a 125 milliliters per minute.
00:15
The glomerular
filtration rate or GFR
is directly proportional
to the net filtration pressure
where the primary pressure
is going to be our glomerular
hydrostatic pressure.
00:28
Also, the GFR is proportional
to the total surface area
available for filtration.
00:36
Here,
the glomerular mesangial cells
are going to control this
surface area by contracting.
00:44
Finally GFR is
directly proportional
to filtrate membrane
permeability.
00:50
Which is much more permeable
than the other capillaries
that we find
throughout the body.
00:58
A constant GFR is
important as it allows
for our kidneys
to make a filtrate
and maintain our extra
cellular homeostasis.
01:08
The goal of local intrinsic
controls are renal autoregulation
is to maintain this
GFR in our kidneys.
01:18
Our GFR also affects our
systemic blood pressure.
01:22
An increased GFR causes
an increased urine output
with lower blood
pressures and vice versa.
01:31
Also, we have extrinsic controls
which are necessary to maintain
our systemic blood pressure.
01:38
Our nervous system and
our endocrine system
are going to be the
main extrinsic controls
of the kidney.