lung development

Definition

Target type: biologicalprocess

The process whose specific outcome is the progression of the lung over time, from its formation to the mature structure. In all air-breathing vertebrates the lungs are developed from the ventral wall of the oesophagus as a pouch which divides into two sacs. In amphibians and many reptiles the lungs retain very nearly this primitive sac-like character, but in the higher forms the connection with the esophagus becomes elongated into the windpipe and the inner walls of the sacs become more and more divided, until, in the mammals, the air spaces become minutely divided into tubes ending in small air cells, in the walls of which the blood circulates in a fine network of capillaries. In mammals the lungs are more or less divided into lobes, and each lung occupies a separate cavity in the thorax. [GOC:jid, UBERON:0002048]

Lung development is a complex and intricate process that begins early in embryonic life and continues until adulthood. It involves a series of coordinated events, including the formation of the respiratory tract, the branching of the airways, the differentiation of specialized cell types, and the establishment of functional gas exchange.

The development of the lung begins in the fourth week of human gestation. The respiratory system originates from the ventral portion of the foregut, a tube-like structure that forms the primitive digestive tract. This region, known as the respiratory diverticulum, grows and eventually separates from the foregut, forming the trachea and the lung buds.

The lung buds then undergo a series of branching events, giving rise to the bronchial tree. This process, known as bronchiogenesis, involves the proliferation and differentiation of epithelial cells. The branching pattern is highly organized, with the main bronchi dividing into lobar bronchi, segmental bronchi, and ultimately, into terminal bronchioles.

As the airways branch, they become surrounded by mesenchyme, a loose connective tissue. The mesenchyme provides structural support and plays a crucial role in the development of the lung parenchyma, the functional tissue of the lung.

The development of the lung parenchyma involves the formation of alveoli, the tiny air sacs where gas exchange occurs. This process, known as alveologenesis, begins around the 24th week of gestation and continues until birth. The alveoli are lined with epithelial cells, including type I pneumocytes, which are responsible for gas exchange, and type II pneumocytes, which produce surfactant, a substance that reduces surface tension and prevents the alveoli from collapsing.

During fetal development, the lungs are filled with fluid, which is gradually replaced by air at birth. This process, known as lung aeration, is essential for the establishment of functional gas exchange.

Lung development continues after birth, with the alveoli increasing in number and size until adulthood. The process of lung development is influenced by a complex interplay of genetic and environmental factors.

Genetic factors play a crucial role in the regulation of lung development, with mutations in certain genes leading to congenital lung diseases. Environmental factors, such as prenatal exposure to smoke, can also have a significant impact on lung development and may increase the risk of respiratory diseases later in life.'
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Proteins (30)

Compounds (937)