LIVER & Pancreas Hepatic veins LIVER W Beresford

LIVER & Pancreas Hepatic veins LIVER W Beresford Bile GI worm Portal vein Hepatic artery Liver is the blood-processing glandular intermediary between you and your G-I worm (tract) that determines blood quality in two ways METABOLIC by

Hepatocytes PROTECTIVE by Kupffer cells (MFs) Questions 1 How do hepatocytes (& Kupffer cells) get access to slow-moving blood? 2 How is bile produced and collected as a fluid separate from blood? HEPATIC PARENCHYMA epithelial working tissue Plate of hepatocytes Endothelial cells blood SINUSOID

Kupffer cell Plate of hepatocytes SINUSOID Space LIVER: low-power section Mesotheliumclad Capsule BD PV HA Portal triad Central vein BD bile ductule PV

portal venule HA hepatic arteriole CV Sublobular vein Lobule LIVER: low-power section Capsule BD PV HA Hepatic parenchyma

Portal triad Central vein Portal triad lies in CT comprising a Portal area CV Sublobular vein at the edge of lobule Lobule BLOOD & BILE FLOWS IN THE LIVER SUBLOBULAR VEIN 6 5

Centripetal blood flow in sinusoids 3 Portal venule INFERIOR VENA CAVA 7 HEPATIC VEIN 4 CENTRAL VEIN Centrifugal flow of bile within plates of hepatocytes in canaliculi 2

Bile ductule Hepatic arteriole 1 PORTAL VEIN Hepatic artery HEPATIC DUCT CELL TYPES & ARRANGEMENT OF LIVER Fenestrated Endothelial cells SINUSOID Kupffer cell STELLATE CELL Hepatocytes in plates

Bile canaliculus Microvilli SPACE OF DISSE HEPATOCYTE ENDOTHELIAL CELL KUPFFER CELL STELLLATE CELL CELL TYPES & ARRANGEMENT OF LIVER Fenestrated Endothelial cells SINUSOID Kupffer cell STELLATE CELL Reticular fiber

Hepatocytes in plates Tight junctions Microvilli Bile canaliculus SPACE OF DISSE Hepatocytes work on plasma, not blood cells, and need time to act. The space of Disse & the fenestrations provide a backwater for the microvillated hepatocytes to work CELL TYPES & ARRANGEMENT OF LIVER Fenestrated Endothelial cells with gut endotoxins & other bad stuff SINUSOID

Reticular fiber Hepatocytes in plates Tight junctions Microvilli Kupffer cell deals Bile canaliculus STELLATE CELL makes collagen fibrils & ECM materials SPACE OF DISSE has ECM materials, but no distinct basal lamina

HEPATOCYTE Microvilli Space of Disse Lysosome PEROXISOME Tight junction Glycogen GOLGI Golgi complex Smooth ER Mitochondrion

GER Bile canaliculus ZONES IN LIVER PARENCHYMA* Peri-portal zone Portal vein branch } } Lobule Central vein Peri-venous/ pericentral zone GALL BLADDER* Highly folded & outpouching T MUCOSA with regular simple columnar epithelium

Thin T MUSCULARIS T SEROSA except where gallbladder attaches to liver PANCREAS Duodenum Enteroendocrine cells hormones Exocrine acini digestive enzymes Endocrine islet metabolic hormones Ducts alkaline ions

} Lobule Duodenal papilla EXOCRINE PANCREAS Ducts 1 Exocrine acini } Principal duct Lobule Interlobular duct Intralobular ducts

Intercalated ducts Duodenal papilla EXOCRINE PANCREAS Ducts 2 Principal duct Exocrine acini } Intralobular ducts Lobule Intercalated ducts Interlobular duct Their accompanying

connective tissue creates the skeleton for the gland Duct intruded into the acinus comprises the centroacinar cells Intercalated duct Duct intruded into the acinus comprises the centroacinar cells Only this plane gives the classic centroacinar view Many section planes will miss the duct and show NO centroacinar cells

STIMULI EXOCRINE PANCREAS Controls Acid Fats Peptides Duodenum Enteroendocrine cells CONTROLLER Secretin & CCK + Vagal cholinergic control Exocrine acini RESPONSE HCO3- ions digestive enzymes PANCREATIC ACINAR CELLS

Apically are many zymogen granules awaiting stimulation for release Lipase & amylase are active, but peptidases that could digest the pancreas are stored in the precleaved, inactive, zymogen form Basal region of the cell houses extensive basophilic granular endoplasmic reticulum