Gallbladder: Anatomy and Function

Gallbladder Anatomy and Function

• Gallbladder wall is 1 to 2 mm thick
• The gallbladder is pear-shaped
• The gallbladder has fundus, a body, and a neck; its wall contains mucosa, muscularis, and serosa
• The distal fundus goes beyond the anterior liver border
• The central body makes up most of the gallbladder
• The neck joins the cystic duct and narrows
• The extrahepatic biliary tree is outside the liver
• Right and left hepatic ducts join to form the common hepatic duct (CHD) in the porta hepatis (hilum of the liver)
• The common hepatic duct joins with the cystic duct to form the common bile duct
• The cystic duct links the gallbladder to the CHD
• The common bile duct results from the fusion of the CHD and cystic duct
• The common bile duct is 2 to 9 cm long
• The common bile duct runs behind the duodenum, through the pancreas head, and into the duodenum via the ampulla of Vater to discharge gallbladder contents
• The gallbladder stores and releases bile
• The gallbladder empties into the cystic duct
• The extrahepatic biliary tree serves to transport bile
• Cholecystokinin stimulates gallbladder contraction and stored bile release
• Bile is required for dietary fat intestinal absorption, but the gallbladder itself is not
• 95% of secreted bile acids are reabsorbed in the ileum, returning to the liver via portal blood, a process known as enterohepatic circulation
• The body eliminates Cholesterol evey day

Bile Salts and Lecithin

• Bile salts include cholates, chenodeoxycholates, deoxycholates, lithocholates, and ursodeoxycholates
• Bile salts: Major hepatic products of cholesterol metabolism
• Bile salts are water-soluble sterols
• Bile Salts solubilize water-insoluble lipids secreted by the liver into the biliary tree
• Bile salts promote dietary lipid absorption in the gut
• Lecithin (phosphatidylcholine) is hydrophobic and nonaqueous
• Lecithin (phosphatidylcholine) has minimal water solubility

Gallstones Composition and Formation

• Gallstones are composed of cholesterol, calcium, and bilirubin
• Cholesterol stones: Made mainly of cholesterol monohydrate, found in the gallbladder in >90% of the instances
• Black pigment stones: Composed of bilirubin polymers and calcium, located in the gallbladder and found in approximately 2% of the cases
• Brown pigment stones: Contain calcium bilirubinate, are located in infected bile ducts, and are present in approximately 10% of the instances
• Gallstone formation Mechanisms: Increased cholesterol secretion, Decreased bile acid secretion, or Combination of both
• Factors associated with increased cholesterol secretion in gallstone formation include age, obesity, estrogen treatment, female sex, and pregnancy
• Factors associated with decreased bile acid secretion include terminal ileum inflammatory bowel disease and prolonged fasting
• Cholesterol supersaturation in bile is the most important step that results in gallstone development

Complications of Gallstones

• Gallstones can cause impaction in the cystic duct, that results in acute cholecystitis
• Gallstones can cause billeary obstruction
• Gallstones can cause gallstone pancreatitis

Acute Cholecystitis

• Acute cholecystitis is an abrupt destructive process of the gallbladder
• Acute cholecystitis is frequently caused by stones blocking the cystic duct
• In acute cholecystitis, ~50% of cases are complicated by bacterial infection
• Essential features of acute cholecystitis is Inflammation of gallbladder by stones, ischemia, or substances
• Essential features of acute cholecystitis is Gallbladder wall thickening and pericholecystic fluid
• Essential features of acute cholecystitis include Complications such as perforation
• Acalculous cholecystitis: Seen more frequently in acalculous cholecystitis
• Cholecystectomy within 72 hours is typically curative for cholecystitis

Acute Cholecystitis Pathophysiology

• Calculous acute cholecystitis is caused by blockage of the neck or cystic duct
• Calculus blockage is often caused by gallstones or biliary sludge
• calculus blockage promotes Continued mucus production by the gallbladder with no outlet
• Calculus blockage creates Increased pressure within the gallbladder
• Calculus blockage inhibits Venous stasis, Arterial stasis and causes Gallbladder ischemia and necrosis
• Acalculous acute cholecystitis is is not caused by blockage of the cystic duct, its caused by Bile stasis and ischemia
• Acalculous acute cholecystitis is caused by Blood clotting disorders, No collateral blood supply (complete reliance on cystic artery), Cystic duct anomalies/congenital anomalies, Sphincter anomalies, Cystic Fibrosis, Viruses and Cocaine
• Symptoms of acute cholecystitis: include Right upper quadrant pain, nausea, vomiting, anorexia, and fever
• Other indications of acute cholecystitis include Leukocytosis and Hyperbilirubinemia with elevated liver function tests
• acute cholecystitis can result in Distention/edema
• acute cholecystitis can result in Serosa: Exudate and Hemorrhage
• acute cholecystitis can result in Wall-thickening
• acute cholecystitis can result in Mucosa: ulcers, stones, bile, hemorrhage
• acute cholecystitis complications include Rupture, Fistula, Abscess, Infected stones into biliary tree and Pancreatitis
• acute cholecystitis has mortality rate of 20%

Chronic Cholecystitis

• Chronic cholecystitis is Chronic inflammation of the gallbladder
• Chronic cholecystitis is the most common disease of the gallbladder
• Chronic cholecystitis is more common in the Female sex
• Chronic cholecystitis is Associated with stones in > 90% of cases
• Chronic cholecystitis is Often associated with repeated acute cholecystitis episodes
• Chronic cholecystitis Usually has vague RUQ pain, bloating, and indigestion as symptoms
• In Chronic cholecystitis the Gallbladder can be thickened or shrunken, strong clinical suspicion

Pancreas Location and Anatomy

• The pancreas is 15 cm in length, shaped like the letter J and sideways
• The loop of the sideways J of the pancreas is around the duodenum
• The pancreas parts are divided into the head, body and tail
• The pancreas is a Retroperitoneal organ (except tail)
• The retroperitoneal pancreas is close to the superior mesenteric artery and portal vein
• The Anterior body of the pancreas touches the posterior wall of the stomach
• The Posterior of the pancreas touches aorta, splenic vein and left kidney
• The Pancreatic tail extends to the splenic hilum
• The Orifice of the bile duct is called ampulla of Vater, with a sphincter of Oddi to release bile and pancreatic juice into the duodenum
• Anomalies of the Pancreas: Duct empties into common bile duct, not into ampulla directly
• Anomalies of the Pancreas: Abnormal bud fusion causes annular or heterotopic pancreas
• The pancreas has exocrine and endocrine functions
• Pancreas is divided into the head, neck, body and tail
• Pancreas drains secretions by the main pancreatic duct (with "vent") in major duodenal papilla (papilla of Vater)
• 5-10% of people have accessory pancreatic duct with orifice in minor duodenal papilla
• Pancreas is embedded in fibrous capsule passing in fibrous septa, separating lobuli

Pancreas Function, Exocrine and Endocrine

• Pancreas has exocrine and endocrine functions
• The exocrine function consists of 99% of the cells
• Exocrine function produces pancreatic juice from acinar cells
• Pancreatic juice contains bicarbonate and a lot of enzymes including proteolytic enzymes (trypsinogen, chymotrypsinogen, carboxypeptidase, elastase), lipolytic enzymes (lipase, esterase, phospholipase), saccharide degrading enzyme (amylase), nucleic acid degrading enzymes (DNAse, RNAse)
• Enzymes must be activated in the intestine before they perform their fucntions
• Trypsin catalyzes activation of the other enzymes
• The endocrine function consists of 1% of cells
• The endocrine function consists of a lot of types of hormones
• Hormones are released into the blood
• Glucagon production increases blood glucose concentration; insulin production decreases blood glucose, glucose intake in adipocytes and muscle cells
• Somatostatin production inhibits smooth muscle motility and antagonize gastrointestinal hormones
• Pancreatic polypeptide production regulates pancreatic juice and bile release
• Vasoactive intestinal polypeptide induces glycogenolysis and hyperglycemia to stimulates GI fluid secretion and causes secretory diarrhea
• P substance and serotonin -stimulatates gastrointestinal motility
• Gastrin -stimultes gastric juice release
• Pancreatic polypeptide -stimulates secretion of gastric and intestinal enzymes and inhibits intestinal motility
• Ghrelin - regulation of hunger and energetic metabolism

Acute Pancreatitis

• Acute pancreatitis is inflammatory disease of the exocrine pancreas
• Acute pancreatitis causes acute onset of severe abdominal pain to pancreatic necrosis
• Acute pancreatitis Reversibly injures pancreatic parenchyma
• Acute pancreatitis is caused by gallstones, alcohol and hypertriglyceridemia
• Main histological features of acute pancreatitis: Acute inflammatory cells with hemorrhage and necrosis
• Acute pancreatitis treatment is supportive
• In acute pancreatitis, 20-70% of ptiennts experiece a gallstone attack
• Acute pancreatitis affects the West and the male sex
• Peak prevalence for acute pancreatitis is in the fifth and sixth decades
• Second most common cause is alcohol accounting for 30% of cases
• Mortality of acute pancreatitis ranges from 3% to 20%

Acute pancreatitis symptoms

• Mild to severe epigastric pain
• Nausea and vomiting
• High white blood cell count
• Diffuse fat necrosis
• Peripheral vascular collapse
• Acute tubular necrosis
• Shock
• Electrolyte disturbances
• Endotoxemia
• Releases of cytokines
• Hypocalcemia
• Hyperglycemia.
• Pancreatic pseudocyst
• Walled-off necrosis
• Peripancreatic fluid collection
  • Includes ARDS, acute kidney injury, and DIC
• Diffuse stippled,
• hemorrhagic, and
• black-brown necrosis

Chronic Pancreatitis

• Chronic pancreatitis is the fibroinflammatory syndrome
• Fibroinflammatory Syndrome is histologically parenchymal fibrosis, atrophy, and duct changes with pancreatis
• Fibroinflammatory Syndrome causes pain and symptoms of pancreatic insufficiency
• Pancreatic fibroinflammatory disease causes fibrosis, loss of acinar tissue and duct changes (stenosis)
• chronic pancreatitis histological diagnosis isn't efficient. Clinical and radiological data needs to happen
• Aicoholic pancreatitis: Young to middle aged males
• Obstructive pancreatitis: M = F; wide age range
• Hereditary pancreatitis: M = F; PRSS1 and CFTR related, where it affects very young children
• Hereditary pancreatitis: : M = F; SPINK1 related, where it affects adult patients
• Paraduodenal pancreatitis: Middle aged males with a history of alcohol abuse and smoking
• Alcoholic and hereditary chronic pancreatitis affects the whole pancreas
• Obstructive pancreatitis affects the gland past the obstruction site
• Paraduodenal pancreatitis centers in the groove area
• Alcoholic pancreatitis is caused by prolonged alcohol abuse and other cofactors such as smoking
• Obstructive pancreatitis is by obstruction of man or secondary pancreatic ducts due to mass forming lesions or intraductal stones
• Hereditary pancreatitis comes from germline mutations in PRSS1
• Paraduodenal pancreatitis results from the chronic obstruction of the mini papilla.
• Severe abdominal pain occurs often, often radiates to the interscapular region
• Paraduodenal pancreatitis may be associated with signs and symptoms of duodenal stenosis such as postprandial vomit
• Risk of developing pancreatic ductal adenocarcinoma is increase 10 fold for patients with chronic pancreatitis
• Risk and diagnostic factors are steatorrhea, weight loss, bloating and diabetes

Tumor Types and Pancreatic Ductal Adenocarcinoma (PDAC)

• Neoplasms can arise from any type of cell in the pancreas
• Pancreatic duodenal adenovarsinoma
• Exocrine cells
• Pancreatic ductal adenocarcinoma/PDAC tumor
• A pancreatic ductal adenocarcinoma (PDAC) is an invasive pancreatic epithelial neoplasm with glandular(ductal)differentiation
• It arises from pancreatic ductal epithelia, with elements, desmoplasia, and necrosis
• Poor prognosis: The 5 year survival rate is 6%
• 50% of cases: Head tumors
• 85% of cases distention of the biliary tree and progressive jaundice Heredity syndromes are
• Pertuz-Jeghers
• Familial atypical mole melanoma
• And Lynch syndrome To perform a curative surgery it's called "whipple Resection" This surgery removes cancerous tumors from organs other as well as the stomach and intestines And the sub total pancreaticoduodenectomy with a 2% of morality

Liver Tumors

• Hemangiomas
• Liver cell adenomas Well circumscribed tumors in women tumors is the hepatic adenoma
• It consist of benign Hepatocytes
• Usually asymptomatic and is Incidental diagnosis Hepatocellular Carcinoma A cancerous cells is "cerosis" for the liver <2% of women get cancer but in it most prevalent in Asia One of the biggest reason is "chronic liver cancer 90% of it is primary with liver tumors
• It's a malignancy arising from the thebillery tree It's very uncommon to find
• A 50 - 60 % of of intrapedal cholangiocarcinoma for for hilar cholangioclarcinoa. Metastatic Carcinoma 98% come from the liver from another organ
• Such as the lungs,breasts and colon If someone takes medication while pregnant they can have enlarged
• It's called focal nodular tumor (FNH)