Metabolism of Bilirubin and Hormones

Synthesis and Storage:

Liver regulates blood glucose levels through:
- Gluconeogenesis - synthesizing glucose
- Storing excess glucose as glycogen
Synthesizes:
- Fatty acids and triglycerides from excess carbohydrates
- Lipoproteins (VLDL, HDL, LDL) for lipid transport
- Cholesterol
- Bile salts for digestion and absorption of lipids
- Ketones as a consequence of excess fatty acid oxidation
Synthesizes plasma proteins:
- Blood clotting factors
- Transport proteins
- Albumin for plasma oncotic pressure
- Complement
Stores vitamins A, D, K, and B12, as well as iron as ferritin

Detoxification and Inactivation:

Breaks down fat-soluble compounds through hydrolysis, oxidation, and conjugation
- Converts them to water-soluble forms that can be excreted by the kidneys
Used for removal of substances like testosterone, aldosterone, and bilirubin

Filtration:

Blood from the GI tract enters the liver via the hepatic portal vein, containing nutrients, toxins, drugs, etc.
Kupffer cells in the liver remove foreign particles like bacteria, viruses, and antigens from this blood.

Surface Anatomy:

Ligaments:

Coronary ligament attaches the superior surface of the liver to the diaphragm
Triangular ligaments attach the right and left lobes to the diaphragm
Falciform ligament attaches the anterior surface of the liver to the abdominal wall

Functional Lobes:

Histology:

Classic liver lobule has a central vein and portal triad at the periphery
Portal lobule has the portal triad in the center
Portal triad contains branches of the hepatic artery, portal vein, and bile duct

Vasculature:

Dual blood supply:
- Hepatic artery provides oxygenated blood
- Hepatic portal vein provides nutrients and toxins from the GI tract
Venous drainage via hepatic veins into the inferior vena cava

Gallbladder is a reservoir for bile, located on the visceral surface of the liver
Cystic duct connects the gallbladder to the common hepatic duct
Biliary tree allows bile produced by hepatocytes to drain into the duodenum

Innervation:

Lymphatics:

Steatosis - increased fat buildup in the liver
Steatohepatitis - inflammation of a fatty liver
Cirrhosis - chronic liver damage leading to scarring and failure
Hepatocellular carcinoma - liver cancer often associated with chronic viral hepatitis

Performed to diagnose liver conditions like abnormal liver function tests, malignancy, or fibrosis
Procedure involves taking a small sample of liver tissue using a needle biopsy

Cholelithiasis - presence of gallstones, often asymptomatic
Cholecystitis - inflammation of the gallbladder, often causes pain
Choledocholithiasis - gallstones in the common bile duct
Cholangitis - infection of the bile duct, often due to choledocholithiasis### Small Intestine
The superior part of the pancreas extends from the right crus of the diaphragm and suspends the duodenojejunal junction
The jejunum has a larger diameter, greater surface for digestion, thicker wall, less vascular arcades, thinner mesentery with less fat, and many large, tall mucosal folds
The ileum has a smaller diameter, smaller surface for digestion, thinner wall, more vascular arcades, thicker mesentery with more fat, and less low, sparse mucosal folds

Arterial supply comes from the superior mesenteric artery, which forms jejunal and ileal branches that create arterial arcades and vasa recta
Lymphatic drainage goes to the superior mesenteric lymph nodes, mesenteric lymph nodes, juxtaintestinal lymph nodes, and ileocolic lymph nodes

Sympathetic innervation comes from T9-12 and goes through the sympathetic trunks, greater, lesser, and least splanchnic nerves, and the superior mesenteric plexus, controlling pain
Parasympathetic innervation comes from the posterior vagal trunk and controls motor function

The pancreas is located in the right and left upper quadrants, epigastrium, umbilical, and left hypochondrium
The pancreas has four divisions: head, uncinate process, neck, body, and tail
The pancreas is retroperitoneal in position

The main pancreatic duct is in the body and tail of the pancreas and connects to the hepaticopancreatic ampulla (of Vater) at the major duodenal papilla
The accessory pancreatic duct is in the uncinate process and connects to the minor duodenal papilla
The pancreatic duct has three sphincters: the sphincter of the bile duct, the sphincter of the pancreatic duct, and the hepaticopancreatic sphincter (of Odi)

The head of the pancreas is anterior to the transverse mesocolon, posterior to the IVC, right renal vessels, and left renal vein, and lateral, superior, and inferior to the duodenum
The neck of the pancreas is anterior to the pylorus and posterior to the SMA/V and portal vein
The body of the pancreas is anterior to the omental bursa and posterior to the aorta, SMA, splenic artery, L2, left suprarenal gland, left kidney, and left renal vessels
The tail of the pancreas is posterior to the left kidney, lateral to the splenic hilum, and inferior to the left colic flexure

The body and tail of the pancreas are supplied by the splenic artery, gastroduodenal artery, and superior mesenteric artery
The head of the pancreas is supplied by the superior and inferior pancreaticoduodenal arteries
Lymphatic drainage goes to the pancreaticosplenic lymph nodes, pyloric lymph nodes, and superior mesenteric to hepatic to coeliac lymph nodes

Parasympathetic innervation comes from the vagus nerve (CN X) and is motor
Sympathetic innervation comes from T6-9 and goes through the superior mesenteric plexus

Pancreatic cancer typically occurs after the age of 40
There are many types of pancreatic cancers, with ductal adenocarcinoma being the most prevalent
Risk factors include smoking, obesity, diabetes, and others