Alright let's talk about chemical
dipsticks and continue here
Now as far as the explanation's concerned,
The way that this is going
to be done is the following:
We're gonna begin at the top and
we'll begin with the bone marrow
And in the bone marrow,
you're producing tons of RBCs
Okay, now these RBCs will
then be taken at some point
How long does an RBC last?
About 120 days, right?
So after 120 days of life of an RBC,
where does it then go to get destroyed?
It goes to the spleen.
It goes to the spleen so
that it gets destroyed.
And when it does so, it is then
going to release tons of bilirubin.
So this is going to be our brief
discussion at this point,
strictly in terms of bilirubin,
you will see a picture,
this very image in our discussion, we'll
talk about hepatobiliary pathology
All that I'm trying to do here in this
discussion or this lecture series
of urinalysis is for our
understanding of bilirubin
because you may or may not
be familiar at this point
So these RBCs after they get old,
you see that first structure there?
That's the spleen.
That spleen is going
to do then what?
It's going to destroy my RBC
You see that structure next to the spleen?
What is that?
That's the splenic macropage.
What is it doing?
Munch. It's eating.
What is it eating?
It's eating that RBC.
And from your spleen, what are you
gonna release into circulation?
Good, you're gonna release bilirubin.
Unconjugated bilirubin, right?
What does unconjugated bilirubin mean?
It's also called "indirect".
What does that mean in terms
of its characteristics?
It is lipid-soluble.
How can you confirm that?
Remember that patient that I just
gave you, with sickle cell disease?
I told you there was icterus.
Isn't that confirmation of
lipid-soluble bilirubin, unconjugated?
Yes it is.
Now, this unconjugated bilirubin which is
now in your blood, it's lipid-soluble,
you have to make sure
that it doesn't escape.
How can you prevent
this from escaping?
It has a chaperone.
What's the name of that chaperone?
It's called albumin.
So albumin and
do you see where it says
number 2 in the black circle?
That black circle
around number two
is the combination of your unconjugated
bilirubin and your albumin
bringing these two where?
Good, you're bringing it to the liver.
So what's going on at the liver?
What's that mean?
It's taking the lipid-soluble bilirubin
and making it into water-soluble
What's this process called?
What's the name of that enzyme?
Now, all that I'm doing here
is setting you up and reviewing
the metabolism of bilirubin
So that you're clear as to
what's occuring here when you go back
and have your discussion of
your urobilinogen and such.
So now that you have your conjugated
bilirubin, where are you gonna get this?
Do you see where it says biliary tree?
Find it? Good.
So now you get it
into the bilary tree.
Once you get into the biliary tree,
then where are you gonna head up next?
Blood, or intestine please?
So you go into the second part of the
duodenum, I go into the intestine,
What kind of bilirubin?
Conjugated bilirubin only.
The conjugated bilirubin will go through
the intestine and then in your intestine,
You have numerous, numerous
in which you then produce
urobilinogen, don't you?
Now this urobilinogen, this
urobilinogen, depending as to what form
Your stercobilin, or you see where the
urobilinogen is going to the kidney?
Normally speaking, you should have
trace amounts of urobilinogen
in the form of urobilin which gives
you what color of urine?
Good, the normal gold yellow type of
color, not dark yellow but golden
But this is urobilinogen.
So at this point, we have discussed different
forms, different forms of bilirubin
Unconjugated bilirubin, conjugated
The only thing that I wish
to bring to your attention
so you see this as
being one big example
You see where's this bilary tree,
what if there was obstruction?
What kind of obstruction?
Maybe a stone - choledocholithiasis
or something like primary
What'd I say? primary
This is going to cause obstruction
So any conjugated bilirubin
that you produce in the liver,
can you get into the biliary tree?
So what's the only method
that you can leave the liver?
It's with the blood.
So now you end up getting different
components in your kidney don't you?
Meaning to say that you might
get conjugated bilirubin,
you might end up getting some
of that bilirubin as well.
So what you wanna do between this
figure and the previous table
is then add in these specific
pathologies that we talked about
and then go through what it means in
terms of urobilinogen and bilirubin
You do that every single time,
it will all settle in, trust me.
In part two, we'll continue
discussing our urinalysis.