hi let's talk about the pancreas in this video we'll discuss the basic structure features and
orientation of the pancreas the pancreas is an organ of the foregut predominantly
exocrine in nature but it has a very important endocrine function the islets of langerhans
help to regulate blood glucose levels the pancreas is predominantly secondarily retroperitoneal
accepting the tail of the pancreas which is nestled adjacent to the hilum of the spleen
and so both the tail of the pancreas as well as the spleen
are intraperitoneal organs there are four major parts to the pancreas there is the head of the
pancreas which is the most robust part it's through the head that the common bile duct
as well as the main pancreatic duct and if present accessory pancreatic duct will run
and pierce through the wall of the second part of the duodenum to secrete into the lumen the uh
the head also includes a small process called the uncinate process which isn't very well illustrated
here but we'll see it on an upcoming illustration the uncinate process is found just posterior to
these vessels and this would be the superior mesenteric artery and the superior mesenteric vein
so just tucked in posterior to the SMA and SMV is that incident process of the head
adjacent to the head is the neck of the pancreas and contiguous with the neck is
the body of the pancreas that extends sort of superior left laterally out towards the spleen
and the distal portion of the pancreas is the tail of the pancreas now let's take a look at
the relationships of these parts of the pancreas to other organs so the head is very well snuggled
by the duodenum so the duodenum has a nice c-shape to it and that very robust head and all of the
ducts that are conveyed through that robust head are found surrounded by duodenum on three sides
the uncinate process is found posterior to the sma and smv which we've discussed and
we'll see this uh in another illustration quite well the neck of the pancreas
is a really um important and rather complicated anatomically relations wise
part of the pancreas it is immediately posterior to the pyloric part of the stomach it's anterior
to those superior mesenteric vessels and it's also anterior to a very important origin and
that is of the hepatic portal vein so what happens is the superior mesenteric vein arises and meets
with the splenic vein to form the hepatic portal vein and that is just posterior to the neck
of the pancreas to erase some of this the body of the pancreas is found posterior to the stomach and
the tail of the pancreas is found nestled adjacent to the hilum of the spleen so the totality of the
pancreas is secondarily retroperitoneal and the exception is this tail which is intra peritoneal
as a glandular organ of both exocrine and endocrine nature uh the pancreas is going to be
known for its secretions the endocrine portions of the pancreas are going to secrete into capillaries
that will permeate the pancreas whereas the exocrine portions of the parenchyma which are
the majority of the pancreas will secrete into ducts so these ducts all are going to coalesce
into one of two ducts we have the main pancreatic duct sometimes just known as the pancreatic duct
which is going to join with the common bile duct so that is the pancreaticobiliary junction there
where they come together is the hepatopancreatic ampulla sometimes known as the ampulla of Vater
and that ampulla is going to drain through the major duodenal papilla
an eruption of mucosa in the second part of the duodenum and pancreatic juice will be
expelled into the duodenum there as will bile
it is possible for the bile duct and the main pancreatic duct to independently drain
into the second part of the duodenum there may also be although this is not a constant
an accessory pancreatic duct which drains the superior portion of the head of the pancreas
and if it is present it will drain through the minor duodenal papilla these duodenal papillae
are going to be found in the medial wall of the second part of the duodenum the major
duodenal papilla is an anatomical landmark which divides the foregut from the mid gut
and it's typically found distal to the minor duodenal papilla
that main pancreatic duct is sometimes known as the duct of Wirsung the accessory pancreatic duct
is sometimes known as the duct of Santorini if there is any issue of edema here either through
infection or if there is a neoplastic growth affecting the head of the pancreas this can be
very problematic physiologically because it can occlude the flow of bile and of pancreatic juice
into the small intestines and so it can affect secretions into the duodenum
the blood supply of the pancreas is quite extensive and will be the uh
the focus of another learning objective um the pancreas shares quite a bit of blood supply with
the duodenum as one might imagine and there are four major sources of blood to the uh the pancreas
so the gastroduodenal artery which is a branch of the common hepatic artery of the celiac trunk is
one of the major blood suppliers to the pancreas so this will give rise to the
posterior superior pancreaticoduodenal artery the anterior superior pancreaticoduodenal artery
the uh the duodenal arteries which also will give rise to branches to the the head of the pancreas
as well there's an inferior pancreaticoduodenal artery from the superior mesenteric artery or sma
which has anterior and posterior branches which announced the most with those anterior
and posterior superior pancreaticoduonal branches of the gastroduodenal artery the splenic artery
is a very robust and torturous branch of the celiac trunk and that's going to give rise to very
many important branches of of artery which supply the pancreas so for instance the uh the dorsal
pancreatic artery which is then contiguous with the inferior pancreatic artery uh there's also
the uh the great or greater pancreatic artery as well as the artery to the tail of the pancreas
and if that isn't enough we also have branches of jejunal arteries from the superior mesenteric
artery that can supply blood to the pancreas as well in terms of innervation uh sort of the uh
the guideline here is think of the vasculature that serves the organ and the uh the innervation
will follow and that's that's no uh exception uh to that guideline here so uh surrounding the
celiac trunk is the celiac plexus which derives its fibers from the thoracic splanchnic nerves as
well as the posterior vagal trunk sympathetics from the thoracic splanchnic parasympathetics
from the posterior vagal trunk and so those fibers will be conducted along the celiac
artery and its branches to the pancreas also any arterial branches from the superior mesenteric
artery located there from the superior mesenteric plexus will also serve the pancreas so
parasympathetic stimulation rest and digest will lead to exocrine secretion as well as vasodilation
so an active pancreas whereas sympathetic stimulation will lead to vasoconstriction and
the inhibition of exocrine secretion so quite the opposite of rest and digest there general
visceral afferent or gva fibers that conduct visceral pain will follow sympathetic fibers
here so referred pain from the pancreas will be to the epigastric region so we've discussed
the pancreas its parts their orientations in relative locations to other structures
the pattern of exocrine drainage of the pancreas blood supply to the pancreas as
well as innervation of the pancreas this is your summary slide thank you for your time