In this lecture, I'm going to describe
the histological structure of the kidney,
ureter, bladder, and the male and female urethra.
These organs make up the urinary system.
There're a number of learning outcomes
that I'd like you to achieve at
the end of this lecture. I'd like you to
know the structure of the kidney, and be
able to define a lobule in the kidney,
and then understand the structure of the
nephron and the renal corpuscle. And then,
be able to describe the structure and
function of what the glomerulus is all
about, and how it filtrates
the blood and forms an ultrafiltrate.
We will then look at the different
tubule systems that make up the nephron,
and it's important that you understand
how to identify each of those tubules,
because it's important to relate the
structure of these tubules to the
function that they carry out when you
learn physiology of the kidney in
physiology lectures. It's also important
to understand the role of the macula
densa and the juxtaglomerular apparatus.
The blood supply to the kidney is also
very important, particularly, to supply
to the nephron and the vasa recta. It's
also important when you look at
the kidney to be able to differentiate
cortical and juxtaglomerular
nephrons. And finally, you should be
able to describe the structure of the
bladder, the ureter, and also the
urethra in the male and the female.
The kidney is very important. It
removes all the toxins of the body.
These four dot points summarize the
function of the kidney. It removes toxins
and also retrieves back from the filtrate,
substances and water that the
body needs. The kidney has a role in
adjusting blood pressure, an acid-base
balance of all the body fluids. It
produces the hormone erythropoietin and
also assists in the production of vitamin D.
And I want you to remember
this as we go through this lecture. I'm
not going to mention these last
functions of the kidney except now. But
I want you to be able to recall later on
when I talk about the peritubular capillary
plexus around the nephron that those
endothelial cells secrete erythropoietin
when they detect that the oxygen
levels are low in those capillaries. And
erythropoietin then stimulates
the bone marrow to then release more
red blood cells, and therefore hopefully,
increase the oxygen content in the blood.
And vitamin D is converted into an
active form by the cells of the proximal
convoluted tubule, and vitamin D is very
important in bone growth, in bone
development, and calcium levels.
So although we won't mention this again, just
remember these two functions, and
also, remember the component of the
kidney that carries out these two