hi let's talk about the kidneys so the kidneys interestingly enough as they're described by
many anatomical textbook our kidney bean-shaped structures as tautological as that may sound they
have both superior and inferior poles remember the superior pole is generally around level vertebral
level t11 and the inferior pole around l1 there are also convex lateral borders and a
concave medial border for the kidney which hosts the hilum or the area for the neurovascular to
enter and exit the kidney the parenchyma or the physiologically active tissues of the kidney is
divided between the cortex and the medulla the cortex is found in the most superficial layer
of the kidney and it also invades amongst the medulla as columns so everything that's outlined
there in green would be the cortex the medulla sits nestled amongst the cortex and it's often
referred to as the renal pyramids and this is probably a bad name for it because when
you take into account the three dimensionality of the medulla it's actually shaped like a cone
rather than a pyramid now it's between these these layers the the cortex and the medulla that we have
the nephrons which are the the fundamental unit physiologically of the kidney so that's where
they're working to filter the blood now urine is conducted down collecting ducts that go through
the medulla and end at the renal papilla and so what I'm outlining now are the renal papilla and
these renal papilla surrounded by areas called minor calice's these minor calice's are receiving
the urine from the collecting ducts and then that urine flows from the minor calices into
the major calices and generally kidneys have two to three major calices and then the major
calices coalesce into the renal pelvis and then the renal pelvis feeds into the ureter now one
thing to keep in mind is that these spaces are always illustrated as open or paitent places in
in vivo in life these are actually collapsed in on themselves so there they're not very large
unless they're replete or full of urine that's backed up and so it's it's probably useful to
conceptualize these spaces to to learn them as open but they're actually closed now when we look
at the parenchyma on a cadaveric specimen such as this one we see that the distinctions between
the cortex and the medulla can oftentimes be very difficult to see post preservation so here we can
see cortex and we can see some cortex there and there and there and these dark areas are
medulla we can see a renal papilla there we can see another renal papilla there as well now the
urine that's being conducted first goes into these minor calyce's and you have a better idea here you
can see precisely how narrow these these minor calyce's can be they're they're very small and
collapsed in on themselves and then they feed into major calluses which are a little bigger and then
finally into the renal pelvis which on the cadaveric specimen here you can see really isn't
that large of a space before finally draining into the ureter on the way down to the urinary bladder
the kidneys are for many of our dissections dissections of opportunity meaning that in
order to to reach them you really anteriorly have to go through most of the the GI or the
the digestive system now there are a couple of basic relationships of the the kidneys that that
we should understand so first of all just anterior to the kidneys is going to be the retroperitoneal
membrane which I'll explain on the next slide but just immediately anterior to that is going to be
the duodenum and in the crook of the duodenum we can see the pancreas here and let me outline
so that you can see the kidneys right there and there so we have the the duodenum and the pancreas
lying anterior to the kidneys superior to the left kidney we have the spleen and inferior to it would
be the the splenic flexure of the transverse colon for the right kidney there's actually a
rather large liver which is why the right kidney is usually inferiorly displaced with respect to
the level of the left kidney and we also have the hepatic flexure of the transverse colon so
these these flexors of the transverse colon are generally named for approximately what's
superior to them splenic on the left side and Patek on the right side so now we have an idea
of what's going on in the vicinity of the kidneys now the kidneys join other structures such as the
aorta the inferior vena cava the lion's share of the pancreas portions of the duodenum as being
retroperitoneal structures now the peritoneum is a topic that's addressed within the context
of the digestive system but very quickly it's a membrane that lines the abdominal pelvic cavity
and the viscera contained within that cavity so there's parietal peritoneum on the body
wall and then there's visceral peritoneum on the organs themselves certain organs are going to be
posterior to the parietal peritoneum in what we call the retroperitoneal space so here you can
see a kidney that's been dissected partially and there's still some peritoneum in front of
this kidney now deep to that parietal peritoneum would be a variable amount of para within a renal
fat and then deep to that para renal fat would be the renal fossa sometimes referred to as the
perirenal fossa deep to that renal fascia is the perirenal fat with an eye and I remember I
because it's on the inside of the fossa and that's the fat that's really going to encase the kidney
and hold it firm within the pararenal gutter that perirenal fat can sometimes even invade
the hilum of the kidney and it poses no real harm to the kidney itself it's just there so when we
think about the layers that surround the kidney anteriorly we have the parietal peritoneum then
that's encasing the para renal fat which invests around the renal fascia which surrounds the peri
renal fat so we've talked about the the anatomy of these dynamic filters and some of the parts
of the kidneys and how they relate to other structures in the abdominal cavity thank you