00:01
Welcome!
This lecture we will be
discussing the urinary system.
00:07
The kidney is the major
organ of the urinary system.
00:12
The kidneys,
a major excretory organ
maintain our body's
internal environment
by regulating the
total water volume
and total solute
concentration in water.
00:25
Regulating our
ion concentrations
in our extracellular fluid
and ensuring long-term
acid-base balance.
00:34
Also, it's going to regulate
the total water volume
and total solute
by excreting metabolic
waste, toxins and drugs.
00:44
It's going to produce renin
which is a molecule that
regulates blood pressure
and erythropoietin,
a molecule that regulates
red blood cell production.
00:56
Also in the kidneys,
We're going to
activate vitamin D,
and also carry out
gluconeogenesis if needed.
01:06
It the kidneys are part
of the urinary system
which includes the ureters
which are going to transport
urine from the kidneys
to the urinary bladder.
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The urinary bladder,
which is our temporary
storage reservoir for urine.
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And the urethra,
which is going to transport
urine out of the body.
01:29
While a 180 liters of fluid
go through the kidneys each day.
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The majority of it is
going to be reabsorbed
and only 1.5 liters
will be excreted.
01:41
The kidneys will
filter the blood plasma
about 60 times per day.
01:48
The filtrate is
going to be produced
by glomerular filtration.
01:54
This is basically the blood
plasma - the proteins.
01:59
Urine is going to be
produced from this filtrate.
02:03
And contains our metabolic waste
and all other
unneeded substances
that we want to get
rid of from the body.
02:12
There are three processes
that are going to be involved
in the formation of urine
as well as the adjustment
of our blood composition.
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First,
we have glomerular filtration,
which is going to produce cell
and protein free filtrate.
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After this,
we have tubular reabsorption.
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This is going to
selectively return about 99%
of the substances
from the filtrate
back to the blood
and are renal tubules
and collecting ducts.
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Then we have tubular secretion.
02:49
This is going to
selectively move substances
from the blood
to the filtrate in
the renal tubules
and collecting ducts.