Liver • Histology of accessory organs: Liver (hepa = liver; hepatic--of the liver, hepatocyte, etc.) • Liver's organization is determined by its main function of removing unwanted materials from and maintaining the composition of blood. • 1 Liver • Many functions 2 Liver • Falciform ligament Dark red-brown; Liver lobe Gall bladder Liver lobe Inferior vena cava Liver lobe 3 Liver • Lobules In the shape of polygonal (hexagonal) columns. • Centered on a branch of the hepatic vein, the central vein. Lobule: • • Dense (interlobular) CT 4 Liver • Small central vein • Hepatic parenchyma 5 6 Liver • Hepatocytes 7 Liver • • Hepatocytes Granularity due to 8 Liver Hepatocytes • • Hepatic portal vein carries nutrients to the hepatocytes from the small intestine • 9 Liver Sinusoidal endothelium • Space of Disse • 10 11 Liver • Lipid droplet Hepatic stellate cells 12 HSC Liver Bile canaliculi, tiny channels; between adjacent hepatocytes of the same cord (sheet). • • Bile function 13 He pat te ocy Bile canaliculus Sinusoid 14 Liver Bile salts are polar steroids; two roles: • • 1- Bile salts are emulsifiers • 2- Triglycerides 15 Liver Bile : contain waste molecule derived porphyrin ring of heme groups (and other hemeproteins). • Hepatocytes absorb bilirubin from the blood • 16 Liver • Biliverdin and bilirubin • Hepatocyte malfunction • 17 Liver Bile canaliculi drain into small bile ducts; walls are simple cuboidal epithelium • hepatic ducts (from the liver) cystic duct common hepatic duct gallbladder bile common bile duct store bile pancreatic duct hepatopancreatic duct or ampulla mixture pancreas duodenum 18 pancreatic juice Liver Blood-flow paths within lobule: Blood into the sinusoids at the lobule's periphery, at six outer corners, from two sources: Hepatic lobule Bile duct tributary • Hepatic portal vein tributary • Hepatic artery tributary Portal Triad Central vein to inf. vena cava Surrounded by dense CT • 19 Hepatic lobule Bile duct tributary Hepatic portal vein tributary Hepatic artery tributary Portal Triad Central vein to inf. vena cava 20 Liver Blood leaves the sinusoids via the central vein; tributary of the hepatic vein • 21 Liver • Cirrhosis http://library.med.utah.edu/WebPath/jpeg4/LIVER015.jpg 22 Gall bladder • hepatic ducts Gall bladder (from the liver) cystic duct common hepatic duct gallbladder bile common bile duct store bile pancreatic duct hepatopancreatic duct or ampulla pancreatic juice pancreas mixture duodenum 23 Gall bladder hepatic ducts Arrival of fatty foods in the duodenum (from the liver) • cystic duct common hepatic duct gallbladder bile common bile duct store bile pancreatic duct hepatopancreatic duct or ampulla mixture pancreas duodenum 24 pancreatic juice Gall bladder • Mucosa; • . Adaptation for greater surfacearea; absorption • 25 Gall bladder • Pits and folds vary in orientation 26 Gall bladder Submucosa: generally absent in relatively small gall bladders. • • Muscularis externa 27 Gall bladder • Between SMFs • Pattern of gallbladder SMT • 28 Gall bladder • Tunica adventitia: present 29 Gall bladder • Cholecystitis 30