Abdominal viscera: Liver, Pancreas and Spleen Flashcards
Describe the development of the liver, pancreas and spleen
Liver and gallbladder develop as an outpouching of the foregut in ventral mesentery.
The spleen develops from mesoderm in dorsal mesentery.
The pancreas develops from both a dorsal and ventral bud from the foregut that develops in the mesentery. The ventral bud forms the head and uncinate process, rotates around the bile duct during development to join dorsal bud. Dorsal bud forms majority of the head, neck body and tail.
During development the stomach rotates clockwise and to the left, pushing the spleen to the left and it expands. At the same time the duodenum, dorsal mesentery and dorsal bud of pancreas swings to the right and fuses with the body wall. Massive growth of the liver in the ventral mesentery and fusion to the superior surface of the diaphragm.
What structures come from the foregut?
Stomach, distal oesophagus, liver, gallbladder, pancreas.
what is an annular pancreas?
Annular pancreas occurs when the ventral bud of the developing pancreas splits into two and encircles the duodenum. Can present with failure to thrive, vomiting and poor gastric emptying.
Sometimes detected in US as increase in amniotic fluid as obstruction stops fetus swallowing amniotic fluid.
How does development of the stomach, liver, pancreas and dudodenum finish?
Stomach rotates to left and clockwise by 90 degrees
Liver grows out of ventral mesentery
Pancreas and duodenum become secondarily retroperitoneal.
What is the transverse mesocolon?
Transverse mesocolon is double layered fold of peritoneum (mesentery) that attaches the transverse colon to the posterior abdominal wall.
What are the boundaries of the lesser sac?
Superiorly bound by the liver.
Lesser sac is formed anteriorly by the lesser omentum stretching from the lesser curvature of the stomach to the inferior border of the liver.
Inferiorly bound by the greater omentum, hanging off the greater curvature of the stomach and attaching to the posterior abdominal wall. Posteriorly and inferiorly by the transverse mesocolon.
Posterior wall of the lesser sac is parietal peritoneum overlying the pancreas, kidneys and adrenal glands.
What is the greater sac?
What are the two regions of the greater sac?
Greater sac is all of the peritoneal cavity not included in the lesser sac.
Lies anterior to the liver, lesser omentum, greater omentum.
Split into the supra and infracolic compartments.
Supracolic sits above the level of the transverse colon and anterior to the greater omentum.
Infracolic sits below the transverse colon and behind the greater omentum.
Where does the liver sit within the abdominal cavity?
(surface anatomy)
Liver extends from the 5th rib to the 10 th rib, mostly in the right hypochondrium, but extends to the MCL in the left hypochondrium.
Its inferior border follows the subcostal border, it is in direct contact with the diaphragm and moves inferiorly on inspiration.
What is the bare area?
What is the falciform ligament and what structure ran within this?
Bare area is an area on the superior surface of the liver that is in direct contact with the diaphragm, grows out of the ventral mesentery during development. Rest of the visceral surface of the liver is covered in visceral peritoneum.
Anterior remnant of ventral mesentery that attaches the liver to the anterior abdominal wall is the Falciform ligament.
Within the falciform ligament is the ligamentum teres, remnant of the umbilical vein.
What is the only route into the lesser sac?
Only route into the lesser sac is via the epiploic foramen which is continous with the greater sac.
Describe the ligaments of the liver
Liver has multiple ligaments:
Anteriorly the falciform ligament which contains ligamentum teres, remnant of the umbilical vein.
On the superior surface have anterior and posterior coronary ligaments which border the bare area, and laterally the R and L triangular ligaments.
On the visceral surface the liver is split into right and left lobes by fossa for the IVC and Gallbladder which lie to the right.
To the left of the IVC and gallbladder are the ligamentum venosum superiorly and the ligamentum teres inferiorly.
Also have the hepatogastric ligament connecting liver to the stomach and the hepatoduodenal ligament, connected the liver to the duodenum.
What are the lobes of the liver?
What impression are left on the liver?
liver split into R and L lobes, on the visceral surface by fossa for IVC and the gallbladder.
R lobe is the largest lobe, left lobe is smaller.
The caudate lobe is the smaller superior lobe bound on the R by the IVC and on the left by the ligamentum venosum.
The quadrate lobe is the smaller inferior lobe bound on the R by the gallbladder and on the left by the ligamentum teres.
Impressions left on the liver: To the left is the gastric impression and the oesophageal impression. On the right it the impression of the right kidney and the right suprarenal gland.
What is the porta hepatis?
The porta hepatis is formed by the hepatic artery, the hepatic portal vein and the bile duct as they enter/ exit the liver.
What is the relevance of segementation of the liver?
Liver is divided into 8 functionally independent segments, each with its own arterial and venous supply, and bile drainage. Clinically relevant as a segment of the liver can be resected without affecting the function of the other segments.
What is the blood supply to the liver?
70% from the hepatic portal vein which is formed by the union of the splenic vein with the IMV and SMV.
30% from the hepatic artery which is a branch off the coeliac trunk.
Coeliac trunk divides into left gastric, splenic and common hepatic artery.
Common hepatic artery then divides into R and L hepatic arteries, the R hepatic artery gives off the cystic artery which supplies the gallbladder.
What structure does the hepatic artery run in?
What does it run with?
What is the pringle manouvre?
The hepatic artery runs with the hepatic portal vein and the common bile duct in the free edge of the lesser omentum.
The pringle manouvre is a pinching manouvre, whereby the free edge of the lesser omentum is pinched during surgery after trauma to prevent blood loss from the hepatic vessels.
What regions are drained by the HPV?
What vertebral level does it form at?
HPV formed by the union of the splenic vein, IMV and SMV posterior to the neck of the pancreas at T11.
Receives blood from the spleen, pancreas, stomach, small intestine and large intestine.
What are some of the tribituaries to the hepatic portal vein?
Tribitaries include the R and L gastric veins draining lesser curvature of the stomach and the abdominal oesophagus.
cystic veins from the gallbladder
paraumbilical veins associated with the obliterated umbilical vein and anastomose with veins on the anterior abdominal wall.
What is portal hypertension?
How can it present?
Portal tension occurs when there is increased pressure within the portal venous system, often due to liver disease either cirrhosis or cancer which restricts blood flow, increasing resistance and causing backflow into the portal system.
This can present with splenomegaly and varices at regions of portosystemic anastomosis.
What are the three regions of portosystemic anastomoses?
1) gastro-oesophageal junction between the azygous vein and the left gastric vein which gives off branches that drains the abdominal oesophagus. Portal HTN forms oesophageal varices these are at high risk of trauma and bleeding -> requires emergency tx.
2) rectal varices between the superior rectal vein given off by the IMV and the middle and inferior rectal veins given off by the internal iliac vein.
3) paraumbilical veins on the anterior abdominal wall that anastomose with veins on the anterior abdo wall. Paraumbilical are associated with the obliterated umbilical vein, when portal HTN occurs blood is shunted back into these veins forming caput medusae.
Describe the bile drainage from the liver and gallbladder?
Bile drained from L and R bile ducts that form the common hepatic duct. The common hepatic duct runs in the free margin of the lesser omentum. This is then joined by the cystic duct and forms the common bile duct which passes posterior to the duodenum before emptying into the second part of the duodenum along with the pancreatic duct at the major duodenal papilla.
What is severe pain in the gallbladder called?
What is it caused by?
what is inflammation of the gall bladder called?
Severe pain in the gallbladder is called biliary colic and is caused by contraction of the gallbladder (induced by CCK from small intestine) against an obstructed outflow in the gallbladder neck. Gallstones can lodge within the gallbladder neck (cholelithiasis) or lodge within the bile duct (choledocolithiasis). When the gallbladder contracts against obstructed lumen there is severe pain.
Gallstones represent and infection and inflammation risk, inflammation of the gallbladder is called cholecystitis.
Where does pain from an cholecystitis refer to?
Pain will present on the anterior abdominal wall in the right hypochondrium region and in the epigastric region due to direct irritation of the parietal periotoneum in the area of the inflammed gallbladder.
Pain will also refer to the right shoulder due to irritation of the diaphragm which is innervated by the phrenic nerve C3-5.
How can gallstones cause jaundice?
If a gallstone lodges within the bile duct at the region of the sphincter of oddi, it can obstruct pancreatic outflow as well as obstructing outflow of bile containing bilirubin from the liver and gallbladder store. Leads to hyperbilirubinaemia and yellowing of the skin/ sclera/ mucuous membranes and itchy skin.
