The Liver

Anatomy Largest gland in the body (1.5 kg) Under the diaphragm, within the rib cage in the upper right quadrant of the abdomen Only human organ that can self- regenerate

Anatomy 4 lobes  Major: left & right  Minor: caudate & quadrate Ducts  Common hepatic  Cystic From gallbladder  Common bile Joins pancreatic duct at hepatopancreatic ampulla

Anatomy

Blood flow Hepatic artery  Brings oxygenated blood to liver Hepatic vein  Carries deoxygenated blood away from the liver Hepatic portal vein  Brings blood from small intestine  Deoxygenated but full of nutrients

Blood flow Hepatic portal vein divides into smaller vessels called sinusoids Sinusoids eventually drain into the central vein of the lobule  Eventually drains into the hepatic vein Hepatic vein drains into the inferior vena cava

Bile production Hepatocytes (liver cells) secrete bile Bile is secreted into the canaliculi  To the bile ductules  To the common bile duct  To the gall bladder Storage  To the bile duct  To the small intestine Helps digest fats

Gallbladder anatomy Thin-walled green muscular sac On the inferior surface of the liver Stores bile that is not immediately needed for digestion When muscular wall of gallbladder contracts, bile is expelled into the bile duct

Functions The liver has more than 200 functions, including:  Regulation of blood glucose & glycogen  Storage of nutrients Including iron, vitamin A, & vitamin D  Breakdown of erythrocytes  Bile secretion  Synthesis of plasma proteins Incl globulins, albumin, prothrombin, & fibrinogen  Synthesis of cholesterol  Detoxification of harmful substances

Functions Normal blood glucose = 90 mg/100 mL Liver pulls excess glucose from blood plasma and stores it as glycogen As blood sugar levels decrease, glycogen reserves are converted back to glucose

Functions Adjusts amino acid levels in blood Excess amino acids are deaminated and excreted through the kidney

Functions

What gets broken down? Insulin & other hormones Hemoglobin Toxic substances  Alcohol & drugs Some antibiotics & hormones  Including estrogen & testosterone Converts ammonia to urea Waste products are excreted through the kidneys

Erythrocyte breakdown Red blood cells have a life span of 120 days RBCs weaken and rupture, releasing hemoglobin into the blood plasma

Erythrocyte breakdown Hemoglobin is absorbed by phagocytosis by Kuppfer cells in the liver Hemoglobin is split into:  Heme groups Iron is removed from heme  Iron is carried to bone marrow  Used for hemoglobin in new RBCs Remaining substance = bilirubin  Becomes bile pigment  Globins Hydrolyzed into amino acids and returned to blood

Erythrocyte breakdown

Problems with excessive alcohol consumption Metabolized alcohol may still be toxic to cells Healthy liver cells are replaced with fibrous scar tissue  Reduces ability to metabolize carbohydrates, fats, & proteins  Reduces ability to transport materials through the body Blood flow is blocked to and from the liver Over time, this may lead to nutritional deprivation & increased susceptibility to infection

Problems with excessive alcohol consumption Long term alcohol abuse results in 3 primary effects on the liver:  Inflammation – swelling of damaged liver tissue  Fat accumulation  Cirrhosis – build up scar tissue left in areas of liver destroyed by prolonged alcohol exposure

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