00:01
Alright, so we've looked at
142 liters of blood flow every day.
00:06
Let's talk about how that blood flow
actually enters
and exits your kidneys.
00:11
So blood flows into your kidneys
from the renal artery.
00:14
Alright, so blood comes in
via the artery,
blood exits
through the renal vein.
00:21
Now these guys are hooked up
to the major vessels.
00:24
The renal artery
is connected to the aorta.
00:26
Remember,
that's the major vessel
that brings oxygenated blood
from the heart
to the rest of the body.
00:32
The renal vein is hooked up to the
inferior vena cava.
00:36
That's going to take
the used of blood
back to the heart to be oxygenated
again through the lungs.
00:42
So, renal in,
artery.
00:44
Renal out,
renal vein.
00:47
Good job.
00:48
So that's the blood supply.
00:50
Now remember,
of the 142 liters of blood
that's going in and out
these suckers
What we have
is urine,
only one to two liters.
00:59
But how does that leave?
Well, that goes out
through the ureters.
01:02
Each one of the kidneys
has a ureter.
01:05
Now, when that isn't flowing well,
we can have
all kinds of problems
in your kidneys.
01:11
Now think about those
blood supplies.
01:13
What if somebody has
high blood pressure?
Well, that blood is just banging
through that kidney.
01:18
That's why people with
high blood pressure
really risk problems
in their kidneys.
01:23
What if they have a kidney stone,
that something
breaks loose in the kidney
and travels into that ureter,
and it blocks off the urine flow.
01:31
Now you've got stuff flowing,
backing up into the kidneys
and causing real problems.
01:36
So see,
this is why
it's very important
that you understand
the basic anatomy of the kidney
before we move into
problems with the kidney.
01:44
So just for fun,
stop right here
and see if you can do
from the layers
from the inside
from the renal medulla
all the way out.
01:52
See if you can name those again.
01:54
Just to help refresh your memory.
02:00
Okay, let's focus in on the
renal artery.
02:02
You see, we know that blood
comes to the kidney
through the renal artery.
02:05
We already have that part down.
02:07
But here's where it gets
super cool,
because that renal artery
comes off the aorta,
and then the renal artery
smaller than the aorta,
and then the renal artery
branches into
progressively smaller
and smaller blood vessels
until the blood reaches
the nephrons.
02:24
Alright, look at that pop out box
we have there.
02:26
That's a nephron.
02:28
Now we're going to talk
more about that.
02:29
but this is pretty cool
what actually goes on here.
02:33
Now see where we are,
are we in the medulla
or the cortex?
Well, stay tuned
because I'm going
to tell you.
02:39
but you've got the medulla
and the cortex there.
02:42
We've got the nephron
which is the working unit
of the kidney.
02:45
Now what relationship is the
renal artery to the nephron?
Keep in mind
the renal artery
keeps branching into
smaller and smaller vessels
until it reaches the nephrons.
02:58
Okay, I have another question
for you.
03:01
What do Egypt and your kidneys
have in common?
Answer?
Pyramids.
03:07
Right?
All right, hang with me.
03:09
That's nerd humor.
I know.
03:11
But let's take a look at
what that means.
03:13
Renal pyramids are these
triangular shaped tissue masses.
03:17
Now, they're located in the medulla
of each of your kidneys,
and they're made up of this dense
network of nephrons.
03:24
Okay, now that's a lot of
information.
03:26
Let's back it up a little bit.
03:28
Take a look at the picture
of the kidney.
03:30
Alright, look,
you see the medulla.
03:33
Then you've got
the cortex,
and you've got
the capsule.
03:37
See if you can write
those structures in
on your notes.
03:40
Just as a way
to use spaced repetition
in practice
in your brain.
03:44
That will help you
remember it more
as we go through
other content.
03:47
Alright, so
they have pyramids,
because they're triangle shaped.
03:52
They're in the medulla
and they're made up of a dense
network of nephrons.
03:57
Now we introduced you again
to the nephron
in the previous slide.
04:01
We're gonna break that down
a little bit more.
04:03
But I want you to keep in mind,
the structures that we have here
and what their job is.
04:08
So in the cortex, you also have
nephrons of the kidney.
04:12
Now they're perfused by the
renal artery arterioles.
04:15
Okay,
renal artery arterioles.
04:19
What does that mean?
Well, you know that blood
comes into the kidney
by the renal artery.
04:24
Remember the renal artery branches
off the aorta.
04:27
Arterioles are just smaller branches
of that renal artery.
04:33
So renal artery
down to the arterioles.
04:36
We have the same thing with the
renal vein venules.
04:39
So see, we see
the numbers for you.
04:41
They're showing up
on the nephron.
04:42
Just to kind of give you
another frame of reference
of how we've represented there.
04:46
You also have the
glomerulus capillaries.
04:49
Okay, so in the
renal cortex,
this is where the nephrons
of the kidneys
are perfused by
the blood vessels,
the renal artery arterioles,
the renal vein venules
and the glomerular capillaries.
05:03
Now this is where it gets
really fun.
05:05
But before we go forward,
I just want you to have
a frame of reference
on what we're talking about again.
05:11
you have the artery,
and the smaller versions of that
the arterioles,
the veins,
the smaller versions
the venules
and the glomerular capillaries
which are very small.
05:23
Another thing that happens
in the renal cortex
is the production of
erythropoietin.
05:27
Now, that one is a killer
to spell.
05:30
But what it is,
is it's a hormone.
05:33
and this hormone is necessary
for the synthesis
of new red blood cells.
05:38
See, this is why people
in renal failure
have very low
red blood cell counts.
05:44
They're anemic
and really, really tired.
05:47
Because they don't have
red blood cells.
05:49
They don't have enough oxygen
being to the going perfuse to all
the rest of their tissues.
05:55
So people with kidney problems
don't have enough
erythropoietien
and so they have
low red blood cell counts.
06:03
So erythropoietin is a killer
if you're trying to spell it,
but it's a super important hormone
in your body.
06:10
Now, the reason we're talking about
it here
is because that happens
in the cortex of your kidneys.
06:17
Now the nephron.
06:19
I have been so excited
to get to this part.
06:21
This is the functional unit
of the kidney.
06:24
Now, each one of your kidneys
has about a million nephrons.
06:30
Now nephron stretch
from the cortex to the medulla.
06:33
Remember, I asked you
is a nephron
in the cortex or the medulla?
Yeah, that's like a nursing school
trick question.
06:40
It's in both.
06:42
Now, the medulla is in the middle
the cortex is on the
outer side of the kidney.
06:47
But the nephron stretches into both.
06:50
There's three main parts
of a nephron.
06:52
Now, I've got on the slide,
the distal convoluted tubule
and the proximal convoluted tubule.
06:57
We'll talk more about those
in other videos.
07:00
What I want you to focus on
is the glomerulus.
07:03
So we're going to blow that up
big for you.
07:05
Now the glomerulus is an amazing
part of your nephron.
07:09
You have the Bowman's capsule,
and then the actual glomerulus
is in the center.
07:14
Now, we'll talk about
what the glomerulus is.
07:16
It's just this tangle
of capillaries,
and it's surrounded by
Bowman's capsule.
07:22
So again,
I want you to make sure
that you have this solid
before we keep moving forward.
07:27
Three main parts of the nephron
that stretches from the cortex
and the medulla.
07:33
You've got the DCT,
the PCT,
and the glomerulus.
07:39
So let's look at the glomerulus
that's surrounded by
Bowman's capsule.
07:43
You see them both
highlighted there.
07:45
The glomerulus is just this
tangle of capillaries.
07:48
They're really, really small,
but they're
really, really powerful.
07:52
So when blood enters
into the glomerulus
- remember we talked about
blood supply.
07:57
The aorta,
then the renal artery,
then down to the arterioles
you've got the blood
flowing into this glomerulus
at the rate of your
blood pressure.
08:06
Now if that blood pressure is just
hammering that glomerulus
you're gonna start to have some
real renal damage.
08:12
But let's say for now
we're talking about
a healthy kidney
with a normal blood pressure.
08:17
So that blood pressure
is going to push that blood
into the glomerulus
at the same force
as your blood pressure is
and it will force
water and solutes
out of the capillaries
and into the lumen of the
Bowman's capsule.
08:30
Okay, so got it.
08:32
You see the blood supply
that goes in,
it gets forced into
the glomerulus
and the wastes and solute
in water
gets forced out of the capillaries
into the Bowman's capsule.
08:43
So we're talking about
water, salts, amino acids
and waste
that make it from the glomerulus
into the capsule,
we call that filtrate.
08:52
Alright, so make yourself a note
on the side
filtrate is
and see what you can recall.
08:58
You don't have to necessarily
list all those things
which you want
to keep in mind,
it's going to be
water,
it's going to be
solutes.
09:05
Specifically,
amino acids and waste products.
09:09
Alright, so you've got that
kind of as a frame of reference.
09:11
So we've got blood
entering the glomerulus,
right.
09:16
By the force of our
blood pressure,
then it gets pushed out of those
capillaries into Bowman's capsule.
09:23
Now the filtrate is filtered
from the blood into the tubules.
09:26
Remember,
we talked about those,
the PCT and the DCT.
09:30
That's why this first stage is
called filtration.
09:33
Now you think about your kidneys
filtering things.
09:36
This is what we're talking about,
it's what happens
in the glomerulus.