Anatomy - Biliary tree, small intestine and pancreas Flashcards
Describe jaundice (icterus)
What causes it?
A buildup of bilirubin in the blood
Describe the normal journey of bilirubin
RBCs broken down in the spleen
–>
Bilirubin goes to the liver where it is incorporated into bile
–>
Bile is secreted into the 2nd part of the duodenum
Describe the biliary tree
Right and left hepatic ducts fuse to form the common hepatic duct
The cystic duct (from the gallbladder) fuses with the common hepatic duct to form the common bile duct
Merges with the main pancreatic duct
Makes the ampulla of Vater
Drains into the 2nd part of the duodenum
Describe the ampulla of Vater
The biliary tree and main pancreatic duct merge to form the ampulla of Vater
this is a wider section that feeds into the 2nd section of the duodenum via the sphincter of Oddi and the major duodenal papilla
Describe the sphincters of the biliary tree
Composition?
Names?
Locations?
Functions?
circumferential smooth muscle sphincters
There are 3:
- bile duct sphincter
- pancreatic duct sphincter
- sphincter of Oddi
Function:
Bile duct sphincter:
- controls the flow of bile
Pancreatic duct sphincter:
- controls the flow out of the main pancreatic duct
Sphincter of Oddi:
- Prevents duodenal chyme and juice entering the biliary tree
Describe an endoscopic retrograde chalangiopancreatography
Endoscope is inserted orally, and goes to the duodenum
Secretes dye up the biliary tree
Radiography is then used to image and treat the biliary tree
(CAN be used directly for treatment)
Describe post-hepatic jaundice
Jaundice that is caused by a biliary tree obstruction
gallstones/pancreatic enlargement --> biliary tree obstructed --> back pressure up the tree --> bile is stuck in the liver --> bile (and bilirubin) spills into the blood
Describe the pancreas
- anatomical relationships
- relationship with the peritoneum
- parts
5 parts:
- Head (in the “C” of the duodenum)
- Uncinate process
- Neck
- Body
- Tail
It is retroperitoneal, lies against the posterior abdominal wall
stomach = anterior
splenic vessels = superoposteriorly
posterior = right kidney, IVC, aorta, bile ducts, sup. mesenteric vessels
Describe the function of the pancreas
Exocrine:
- produces digestive enzymes into the duodenum, via the main pancreatic duct
Endocrine:
- makes insulin and glucagon
Describe the control of the pancreas
Hormonal:
- Majority of control
- by hormones from the duodenum
Innervation:
symp = abdominal splanchnic
para = vagus
They from the celiac and sup. mesenteric plexuses, and then go perivascularly
Which arteries supply the pancreas?
Pancreatic arteries (from the splenic)
Sup. pancreaticoduodenal artery
Inf. pancreaticoduodenal artery
Describe pancreatic pain
Cause?
Location?
Referred pain?
Often due to pancreatitis
Caused by:
Ampulla of Vater getting blocked by a gallstone
–>
Bile goes into main pancreatic duct and pancreas
Pain:
- epigastric/umbilical region
Referred pain:
- midline back, between shoulder blades
Name the 3 parts of the small intestine
Which parts are foregut and which are midgut?
duodenum --> jejunum --> ileum
Foregut:
- first 2 parts of the duodenum
Midgut:
- everything else
List the 4 parts of the duodenum
Describe their relationship to the peritineum
1- superior (duodenal cap)
2- descending
3- horizontal
4- ascending
Intraperitoneal:
- duodenal cap
Retroperitoneal:
- descending, horizontal, and ascending
What marks the start and end of the duodenum?
starts = pyloric sphincter
end = duodenal-jejunal flexure
Describe the blood supply of the duodenum
Sup. pancreaticoduodenal artery
Inf. pancreaticoduodenal artery
Describe the locations of the duodenum, jejunum, and ileum in the abdomen using the quadrant system
Duodenum:
- left and right upper quadrants
Jejunum:
- Left (and right) upper quadrants
- left lower (a bit)
Ileum:
- right and left lower quadrants
- right upper (a bit)
What marks the end of the ileum?
ileocaecal junction
Describe the differences in the walls of the jejunum and ileum
Wall width:
- Wall thickness decreases down the tract
Plicae circulares:
- folds become less down the tract
- (ileum is smoother)
Lumen width:
- Decreases down the tract
Describe the blood supply of the jejunum and ileum
sup. mesenteric artery
–>
jejunal and ileal arteries
(Vessels travel in the mesentery)
Describe the venous drainage of the jejunum and ileum
jejunal and ileal veins --> sup. mesenteric vein --> hepatic portal vein
Describe fat absorbtion
Chylomicrons in lumen --> lacteal --> lymphatics --> left venous angle
Describe the lymph nodes of the abdomen
Most surround the arterial trunk
- Celiac
- sup. mesenteric
- inf. mesenteric
- lumber
