Associated Glands of the GIT

Flashcards covering anatomy, blood supply, biliary structures, and clinical applications for the liver, gallbladder, spleen, and pancreas.

Liver

The largest gland in the body and the largest single organ after the skin, weighing approximately $1500\,g$ and accounting for approximately $2.5\%$ of adult body weight.

Hematopoietic organ

A role the liver serves in the late fetus, where it is proportionally twice as large, accounting for $5\%$ of body weight.

Liver Location

Occupies almost all of the right hypochondrium and epigastrium, and extends slightly into the left hypochondrium.

Subphrenic recesses

Superior extensions of the peritoneal cavity (greater sac) existing between the diaphragm and the anterior and superior aspects of the diaphragmatic surface of the liver.

Falciform ligament

A ligament that extends between the liver and the anterior abdominal wall, separating the subphrenic recesses into right and left recesses.

Hepatorenal recess (Morison’s pouch)

The posterosuperior extension of the subhepatic space lying between the right part of the visceral surface of the liver and the right kidney and suprarenal gland.

Bare area of the liver

A posterior region on the diaphragmatic surface where the liver lies in direct contact with the diaphragm, demarcated by the reflection of peritoneum as the coronary ligament.

Porta hepatis

A transverse fissure on the visceral surface transmitting neurovascular structures (except hepatic veins) and providing attachment for the lesser omentum.

Ligamentum teres

Also known as the round ligament, it forms the anterior part of the left sagittal fissure of the liver.

Quadrate lobe

An accessory lobe on the visceral surface demarcated anteriorly and inferiorly by the right and left sagittal fissures and the porta hepatis.

Caudate lobe

An accessory lobe on the visceral surface demarcated posteriorly and superiorly; it has independent vascularization from the portal triad bifurcation.

Liver Blood Supply (Venous)

The portal vein brings $75$ to $80\%$ of the blood to the liver, containing about $40\%$ more oxygen than systemic blood and carrying all nutrients except lipids.

Liver Blood Supply (Arterial)

The hepatic artery accounts for $20$ to $25\%$ of the blood received by the liver, distributed initially to non-parenchymal structures like intrahepatic bile ducts.

Hepatic veins

Formed by collecting veins that drain central veins, there are right, intermediate, and left veins which open into the IVC just inferior to the diaphragm.

Hepatomegaly

Enlargement of the liver that can occur due to congestive heart failure, hepatitis, or tumors, often palpated below the right costal margin.

Cirrhosis of the Liver

Progressive destruction of hepatocytes and their replacement by fat and fibrous tissue, most frequently caused by chronic alcoholism.

Biliary Ducts

Convey bile from the liver to the duodenum; bile is produced continuously by hepatocytes into bile canaliculi.

Bile duct (Common bile duct)

Formed in the lesser omentum by the union of the cystic duct and common hepatic duct, measuring $5$ to $15\,cm$ in length.

Hepatopancreatic ampulla (of Vater)

The dilation formed by the union of the bile duct and main pancreatic duct, opening into the duodenum through the major duodenal papilla.

Sphincter of Oddi (Hepatopancreatic sphincter)

The smooth muscle sphincter around the hepatopancreatic ampulla that controls the flow of bile and pancreatic juice.

Gallbladder

A pear-shaped cystic structure ($7-10\,cm$ long) that holds up to $50\,mL$ of bile and lies in a fossa on the visceral surface of the liver.

Parts of the Gallbladder

The fundus (projects from the inferior border), the body (contacts the liver and duodenum), and the neck (joins the cystic duct).

Spiral fold (Spiral valve)

A structure in the mucosa of the cystic duct neck that helps keep the duct open.

Cholelithiasis

Gallstones typically composed of cholesterol crystals; if they block the cystic duct, they cause biliary colic and cholecystitis.

Spleen

The largest lymphatic organ, located in the left upper abdominal quadrant; it removes expended RBCs and serves as a blood reservoir.

Splenic Hlium

The only part of the spleen not surrounded by peritoneum, where splenic branches of the artery and vein enter and leave.

Splenectomy

Surgical removal of the spleen; total removal is generally non-vital as other reticuloendothelial organs assume its functions.

Accessory Spleen

A small nodule of splenic tissue (about $1\,cm$ diameter) found in approximately $10\%$ of people, often near the hilum or tail of the pancreas.

Pancreas

An elongated, retroperitoneal accessory digestive gland with both exocrine (pancreatic juice) and endocrine (glucagon and insulin) functions.

Uncinate process

A projection from the inferior part of the pancreatic head that extends medially to the left, posterior to the SMA.

Main pancreatic duct

Begins in the tail of the pancreas and runs to the head; it usually unites with the bile duct to form the hepatopancreatic ampulla.

Pancreatitis

Inflammation of the pancreas occurring from infection or bile reflux into pancreatic tissues.

Obstructive jaundice

A condition caused by retention of bile pigments, often resulting from cancer of the pancreatic head compressing the bile duct.