- We're going to start looking at the gross
anatomy of the kidney, and we're going to do it
in two different ways. We're going to look
at a kidney that's just, like, hanging out, and then
we're going to look at a kidney that's been sliced in half. This is my sliced
in half kidney. And I'm actually going
to draw the kidney for you, because I think it's always
valuable to draw pictures of your own structures. But I'm showing you this to let you know what I'm
trying to draw, and I'll probably go back
and forth as we do this. So, let's start by drawing
our actual kidney. And, unfortunately,
my brain cannot handle drawing the kidney in that orientation,
so I have to draw what? That was probably
my left kidney. I'm going to draw
my right kidney. Not that I can tell
my left from my right. And I'm going to
try to make it huge, so that I have enough room
to draw everything on it. And now that I just
made it this huge, I realize there's a structure
that I want to draw on top, that I'm not going to
be able to draw on top. But I'm going to just show
you where it goes, anyway. It's a little triangle-shaped
endocrine gland that sits on top of the kidney,
and it looks like a hat. This is the adrenal gland,
and you have two of them, one on each kidney. And the adrenal
gland does a whole bunch of endocrine function, and you find them sitting
right on top of the kidney. Okay. So our kidney is
surrounded by a layer, and I'm just going to draw
this layer outside of here. And I'm going to make it
kind of get skinny over there, and that's just because I
don't want to get confused about what we're going to find
around this little indentation that makes it look like
a little kidney bean. You have a little bean in you. This is the fibrous
capsule of your kidney, and of course there's
two names for it. It's also called
the renal capsule. It's made of dense,
irregular, connective tissue,
and it's just a covering. And it's found-- there's also layers of fat
that your kidney is kind of, like, embedded in
in the posterior aspect of your abdominal cavity. But we're not going to
focus on those guys. We're just going to focus on
the actual kidney itself. Let's see here. There's this zone
that we shall-- well, how should we do this? This zone right here
is called the hilum. Really?
Oh, I'm pushing a button on pen. No, we don't want to
push that button. Although that's interesting
to know that I can move the whole thing by
pushing that button. The hilum of the kidney is the
location of this indentation, and I tell you that because
there are several structures that come out of the
hilum that are relevant. First of all, we
have a structure that I'm drawing it in yellow,
because I want you to see that it's actually sort of
continuous with this other microscopic structure that
I'm going to draw in here. But this yellow structure
heads to your bladder, and it's called the ureter. It comes directly
out of the kidney. And when we cut the kidney
open and take a closer look, we'll see, like, how the ureter is associated with the
inside of the kidney. Also in the hilum
we have-- okay. I'm going to draw this for you, and then you have to
guess what it is. It's my favorite. Whatever could that be? It's the renal something. Something you already know.
It's the renal artery, and look how huge it is.
It's, like, gigantic. It's way bigger than the ureter, although you can't really
tell that from my drawing. Who else would you expect, if we've got a renal
artery going on, who else are you going
to expect to see in here? Somebody that is most
certainly blue. You've got to have a renal vein. The renal artery,
the renal vein, and the ureter
all exit the kidney in this same place,
in this hilum. I'm just going to make
these little ends, so that you can
see that that's just a blood vessel.
Where do those go? Well, the renal
artery brings blood from the descending
abdominal aorta. The renal vein takes blood
from the kidney back to the inferior vena cava. I think that's everything
that I want to do external. Now imagine we just
chopped our kidney in half, and now we're going
to look inside. And we actually
have a couple of layers, if you will, inside. And I'm going to draw my layers
inside super diagrammatic, but hopefully this
will be clear. This whole area that
is lined by the purple, this is the cortex, and we will see what
kind of anatomical structures are found in
the cortex of the kidney. And the cortex is in contrast
to the medulla of the kidney. So this whole area is the
medulla of the kidney. Now, the medulla has
some significant anatomical structures, and so I'm going to
draw them for you. What? Can you imagine
me doing such a thing? Okay.
First of all, what you have to know
is that my drawing is, of course, very diagrammatic.
There are structures. What do these look like?
Pizza slices. How did you know that?
Oh, my gosh, wouldn't it be fun if somebody out there
actually thought, "They look like pizza slices." Who would think they
look like pizza slices? If you thought pizza slices, you're very strange
just like me. Okay.
Enough pizza slices. These are renal pyramids.
That's easy. Renal pyramid. Fantastic correct the
falsie on an exam could be renal pyramids are found
in the cortex of the kidney. Are they?
No, doggies, they're found in the
medulla of the kidney. Now, we'll look at the
microscopic structure of, like, what makes up a renal pyramid, but the tip of the renal
pyramid has a name. It has a little nipply name. Doesn't it kind of
look like a little nipple? My face-to-face students this this semester actually
made fun of me, because the papillary muscles
I must've said at some point, "They're like little nipples," because papilla means nipple,
damn it. But they're like, "Dude, those don't look anything
like nipples." I'm like, "It's just an expression." These are renal papilla,
like little renal nipples. And look at how many. Each renal pyramid terminates toward the middle of the
kidney in a renal papilla. Now, this is going to
hurt your head, so take a deep breath. The renal papilla is
like a little nipple, and it actually is going to
be able to drip pre-pee. So your kidney is making urine, and before it actually is urine, it's like pre-urine. And the fluid that you are
producing in your kidney is going to drip out of
this little papilla, and here's the amazing thing.
Okay. It drips out,
and there's a little funnel right next to it that's going
to catch the little drops of pee-pee that are
coming out of the papilla on each renal pyramid. So, I'm going
to draw you one of those, and I'm going to draw it in-- I must draw it in
this color blue. I just changed my mind.
I must draw it in orange. That's going to help you. Now, look.
It's a funnel. And so with my highly
limited drawing skills I'm drawing you a funnel. Do you see how if I
had a funnel-- oh, my gosh, I feel like I
really need a funnel. Just like in the lectures
where I really needed spaghetti noodles to
demonstrate something for you, I really need a
funnel right now. And the funnel sits right
next to this, and there's, like, a space in the funnel. And the renal papilla drips
pee-pee into the funnel. The funnel is called
a minor calyx. I'm going to label it out here. This is the minor calyx. The minor calyx is really
contiguous with the ureter, and so it's catching the pee-pee that's being produced
in the renal pyramids. Each renal pyramid
has a minor calyx. And I closed that one off, and I definitely don't
want to close it off, because they're not closed off.
They really are, like, you could put a
marble in the funnel, and it could end up
in your ureter. That'd be bad. That's like kidney stones.
Don't do that. Don't put marbles
in your ureters. Don't put them up your
nose either. Okay. Minor calyces,
that's plural of calyx, combine with other
minor calyces. So this is like we're
funneling into-- look what just happened.
Do you see what I just did? Two funnels, two minor calyces,
come together and make what, do you think?
It's this easy. They make a major calyx.
Okay. So the minor calyx takes
pee from one renal papilla. The major calyx takes pee from
two minor calyces or more, and then guess
what else happens? You can have multiple
major calyces, and they all feed
into the same zone. Okay.
I can't help it. I have to add this
one in here too. Look. And I'm going to
skip these guys, just because I don't want to draw all of those.
But look. Okay. I'm going to put a little green
dot next to my major calyx. There's one, there's one,
here's one, where we're bringing
more than one together. I'm going to put a little red
dot next to my minor calyx. Here's one, here's one, here's one.
You guys are good? You totally get this idea?
Okay. Those are all minor calyces, and they all feed
into the renal pelvis. So part three, renal pelvis. I meant to make that the same
nice color as the other one. What color is that other one? I think it's yellow,
but is it actually orange? My renal pelvis is
the ultimate source. It's the last place where
you're going to find urine in the kidney before it leaves
and goes to the ureter, okay? You know that's okay. There's someone I forgot
in the renal medulla. But you're good, right? You know you're good.
Look. In my medulla these things
between my renal pyramids, what do they look like?
Big ol' columns. And they're renal columns,
I think. Renal columns. Sometimes I'm like, "Seriously,
do we have to name that thing?" Yes, I didn't just say that. Now, the pee is going to
get into the ureter. The ureter we know already
is headed to the bladder. So let's look at that whole
aspect of the urinary system.