Book contents
- Frontmatter
- Contents
- Contributing Authors
- Preface to the Third Edition
- Preface to the First Edition
- SECTION I PATHOPHYSIOLOGY OF PEDIATRIC LIVER DISEASE
- 1 Liver Development: From Endoderm to Hepatocyte
- 2 Functional Development of the Liver
- 3 Mechanisms of Bile Formation and Cholestasis
- 4 The Cholangiopathies
- 5 Acute Liver Failure in Children
- 6 Cirrhosis and Chronic Liver Failure
- 7 Portal Hypertension
- 8 Laboratory Assessment of Liver Function and Injury in Children
- SECTION II CHOLESTATIC LIVER DISEASES
- SECTION III HEPATITIS AND IMMUNE DISORDERS
- SECTION IV METABOLIC LIVER DISEASE
- SECTION V OTHER CONDITIONS AND ISSUES IN PEDIATRIC HEPATOLOGY
- Index
- Plate section
- References
2 - Functional Development of the Liver
from SECTION I - PATHOPHYSIOLOGY OF PEDIATRIC LIVER DISEASE
Published online by Cambridge University Press: 18 December 2009
- Frontmatter
- Contents
- Contributing Authors
- Preface to the Third Edition
- Preface to the First Edition
- SECTION I PATHOPHYSIOLOGY OF PEDIATRIC LIVER DISEASE
- 1 Liver Development: From Endoderm to Hepatocyte
- 2 Functional Development of the Liver
- 3 Mechanisms of Bile Formation and Cholestasis
- 4 The Cholangiopathies
- 5 Acute Liver Failure in Children
- 6 Cirrhosis and Chronic Liver Failure
- 7 Portal Hypertension
- 8 Laboratory Assessment of Liver Function and Injury in Children
- SECTION II CHOLESTATIC LIVER DISEASES
- SECTION III HEPATITIS AND IMMUNE DISORDERS
- SECTION IV METABOLIC LIVER DISEASE
- SECTION V OTHER CONDITIONS AND ISSUES IN PEDIATRIC HEPATOLOGY
- Index
- Plate section
- References
Summary
The liver attains its highest relative size at about 10% of fetal weight at the ninth week of gestation. Early in gestation the liver is the primary site for hematopoiesis. At 7 weeks of gestation, hematopoietic cells outnumber hepatocytes. Primitive hepatocytes are smaller than mature cells and are deficient in glycogen. As the fetus nears term, hepatocytes predominate and enlarge with expansion of the endoplasmic reticulum and accumulation of glycogen. Hepatic blood flow, plasma protein binding, and intrinsic clearance by the liver (reflected in the maximal enzymatic and transport capacity of the liver) also undergo significant postnatal maturation [1]. These changes correlate with an increased capacity for hepatic metabolism and detoxification. At birth the liver constitutes about 4% of body weight compared with 2% in the adult. Liver weight doubles by 12 months of age and increases threefold by 3 years of age.
The functional development of the liver that occurs in concert with growth requires a complicated orchestration of changes in hepatic enzymes and metabolic pathways that result in the mature capacity of the liver to undertake metabolism, biotransformation, and vectorial transport. Greengard [2] has established a paradigm for hepatic development based on a group of several hepatic enzymes studied in the rat and, less extensively, in humans. In one pattern of hepatic development, enzymatic activity is high in a fetus and falls during postnatal development. Examples would include thymidine kinase and ornithine decarboxylase [3].
- Type
- Chapter
- Information
- Liver Disease in Children , pp. 14 - 27Publisher: Cambridge University PressPrint publication year: 2007
References
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