Liver and bile ducts anatomy Liver histology Liver

Liver and bile ducts - anatomy

Liver – histology

Liver function Energy metabolism - saccharides, proteins, lipids n Synthetic processes n Biodegradation and elimination n Blood coagulation n Inner environment homeostasis n Extramedular haematopoiesis n

Test types in hepatology Dynamic tests - measure liver capacity to metabolize exogenous substance Static tests - evaluate immediate metabolic liver situation n n Tests for hepatocytes damage – ALT, AST Tests for bile ducts obstruction – ALP, GGT Tests for liver synthetic function – ALB, p. ALB, CHS Tests measure liver detoxification activity – NH 3, Bil.

Dynamic tests n n n Only liver metabolized substances, non-toxic Tests of liver microsomal function 1. chromoexcretion tests – indocyanine green Procedure: i. v. application (0. 5 mg/kg) – spectrophotometric measurement in 20 th min (more than 4% retention = pathology) 2. other tests - aminopyrine test (13 C-aminopyrine) – detection of 13 CO 2 in exhaled air (NH 6. 6 ± 1. 3 % of applied substance) - lidocaine test – 10 hours starving, application of 1 mg/kg lidocaine i. v. , after 15 min determination of MEGX levels of MEGX below 10 ng/L – bad prognosis

Tests for hepatocytes damage – ALT, AST n Function: transfer of α-amino group from L-aspartate and L-alanine to α-ketone group of glutarate (gluconeogenesis) n ALT – primary localisation in liver, cytosol AST – liver, heart, skeletal muscles, pancreas, kidney, erythrocytes AST – 2 isoforms: a) mitochondrial, b) cytosolic de Ritis index – AST/ALT, value above 1 = hepatocyte necrosis n PR: AST: 0. 16 – 0. 72 μkat/L, ALT: 0. 17 – 0. 78 μkat/L n n Increased activity: hepatitis, toxic liver damage, circulation shock, cirrhosis, neoplasia, metabolic disorder

Tests for bile ducts obstruction – ALP, Cu n ALP – catalyzes hydrolysis of phosphate esters in alkaline conditions - has few isoforms – bone, gut, liver and placental PR: 0. 66 – 2. 2 μkat/L Increased activity 1. hepatic causes – cholestatic disorders, PBC, prim. sclerotic cholangitis, liver processes (absces, sec. tumors, cysts) 2. non-hepatic causes – rickets, bone tumors, leukemia, lymfoms, gut ischemia, gravidity ↑ S-Cu – bile ducts obstruction „marker“ (PR: 11. 6 – 20. 6 μmol/L)

Tests for bile ducts obstruction – GGT n GGT – catalyzes transfer γ-glutamyle group of peptides to other amino acids Localisation: bile duct cells, pancreas, kidney, prostate, heart n PR: men 0. 14 – 0. 84 μkat/L, n n women 0. 14 – 0. 64 μkat/L Increased activity: cholestasis, liver tumors, pancreatitis, AIM, renal insufficiency, chronic alcoholism

Tests for liver synthetic function n n n Albumin – the most important protein synthetized in liver - synthesis about 12– 15 g daily, biol. half 19 -21 days PR: 35 – 53 g/L Deceased levels: cirrhosis, ascites, nephrotic syndrome, burns Prealbumin – biol. half 2 days – better for proteosynthesis estimation PR: 0. 2 – 0. 4 g/L Changes of γ-globulines – polyclonal gammapathy, increased levels of Ig. A, Ig. M, Ig. G Coagulation factors – FBG, prothrombin, V, VII, IX a X - changes of coagulation tests – Quick test

Tests for liver synthetic function n CHE(S) – (acetyl)choline esterase vs. pseudocholine esterase n diagnostic power: decreased activity in serum n Causes: proteosynthesis disorder – hepatopathy, malnutrition intoxication by organic phosphates – insecticides, nerve gases - familiar idiopatic acholinesterasemia - in anaesthesiology - dibucaine number

Tests measure liver detoxification activity – NH 3, Bil. n n n Ammonia – AA metabolism product , ureogenesis disorder marker Bilirubin – metabolism: formation, conjugation, excretion, δ–bilirubin enterohepatic circulation, UDP–glucuronyl transferase, urobilinogen, stercobilinogen, jaundice production 250 -350 mg/day n bilirubin – indirect x unconjugated, soluble in fats bilirubin – direct x conjugated, soluble in water n PR: con-Bil : 2 – 17 μmol/L, uncon-Bil : 0 – 5 μmol/L n

Hyperbilirubinemias n n n Unconjugated – increased bilirubin formation, conjugation disorders Causes: hemolytic anemia, morbus haemolyticus neonatorum, defects of UDP-glucuronyl transferase, Gilbert ; Crigler-Najjar Mixed – hepatocytes damage, conjugation disorders Causes: hepatitis, toxic liver lesion, liver cirrhosis Conjugated – obstruction icterus, excretion con-Bil disorder Causes: obstruction–lithiasis, bile ducts tumors, Dubin-Johnso n; Rotor