Now, turn your attention to the left-hand
diagram, and we're going to describe the
structure of a nephron. Concentrate on,
perhaps, the juxtamedullary nephron
shown there, because it's drawn a little
bit larger and a bit easier then to
understand. On the right-hand side, you
can see circular structures with a
little white hilar around them. They are the
glomerulus in the renal, in the
Bowman's capsule, that's part of the
corpuscle, the renal corpuscle
I'll describe in a moment.
And all the other profiles you see are
going to be profiles through the
tubule system. Go back to the diagram.
Have a look at the juxtamedullary
nephron, and let's just see if we can
remember its components. In the center, there's
a little round red structure. That's the
glomerulus. It sits in Bowman's capsule,
which is also a component of that little
round red structure. And then you have this
tubular system leaving the renal corpuscle
and forming rather a cold blue
colored structure there. It's a coiled tube.
It's proximal to the renal corpuscle.
So it's called the proximal convoluted tubule,
because it's all coiled. And then you
see a straight segment going down towards
the papilla of the medulla.
That's called the descending straight segment.
Then there's a little loop.
It's a thin loop. It's a thin segment. That's
called the thin loop of Henle. And then it
descends as an ascending thin limb of the loop
of Henle, and then joins to a thicker red
colored part of the tubule system. That's
the distal straight tubule as opposed
to the proximal straight tubule you
saw earlier. And then that ascending
distal straight tubule gives rise to
another coiled tubule. That's called
the distal convoluted tubule. And then
that opens into a collecting tubule, and
a series of collecting tubules open
into the collecting duct, which carries
the urine then down and it then drips
from the papilla of the renal pyramid.
So make sure you understand then the
tubule system of the nephron. Proximal
convoluted tubule, descending thick limb,
then thin segment, descending thin segment
loop of Henle, ascending thin limb of Henle,
and then the ascending thick limb or segment
of the distal tubule and then the distal
convoluted tubule emptying into the
collecting tubule and then the collecting
duct. They are the components of
the nephron that function. They do all
the important parts of the kidney does that you'll
get explained to you in your physiology
lectures. Let's now have a look at some of
the histological details of those components.
So if you can imagine a line or
a section taken through that top part
where the renal corpuscle is of the
nephron you've been looking at, you'll
see the sort of image you'll see on the
right hand side.
Again, sections through the renal corpuscle
and profiles through all those convoluted
tubules, the straight tubules you'll see down
towards the lower region and in the medulla.
Here is a diagram explaining the
structure of the renal corpuscle.