Abstract
Lung development begins within 2-3 weeks of conception and is completed when thoracic growth ceases in late adolescence. Human lung morphogenesis largely occurs before birth and during infancy under the control of a genetic program that is modulated by endocrine and physical factors. Lung development occurs by branching morphogenesis which is closely regulated by intrinsic growth factors. After the bronchial tree has been laid down, lung growth occurs by expansion of existing lung tissue rather than by the establishment of new structural units. In the fetus, the development of major lung components including the vascular bed, alveoli, and innervation occurs in parallel such that by the time of term birth, the lung is capable of effective gas exchange. During fetal life, the lung is expanded by liquid, which is critical for tissue growth and remodeling; after birth, growth of the thoracic cage is likely to drive lung growth. The genetic program of lung development can be altered by prenatal and early postnatal challenges leading to lasting effects on lung structure and function. Fetal exposure to adverse intrauterine conditions such as reduced amniotic fluid, excess glucocorticoids, nutritional and oxygen restriction, or maternal tobacco smoking can interfere with the genetic program of development.
Original language | English |
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Title of host publication | Encyclopedia of Respiratory Medicine, Four-Volume Set |
Publisher | Academic Press |
Pages | 613-619 |
Number of pages | 7 |
ISBN (Print) | 9780123708793 |
DOIs | |
Publication status | Published - 1 Jan 2006 |
Keywords
- Airways
- Alveolus
- Angiogenesis
- Branching morphogenesis
- Embryo
- Fetal breathing movements
- Fetal lung liquid
- Fetus
- Growth factor
- Newborn
- Tissue strain
- Type-I cells
- Type-II cells