Congenital malformations of lung

August 12, 2017 17:51 | Genetic Diseases

idea of ​​congenital malformations of lung inextricably linked to the understanding of the basic laws of formation of bronchopulmonary system.Easy man formed continuously from the earliest stages of fetal development and continues throughout childhood.

are allocated 3 periods or stages of embryonic development easy: glandular when developing airways;canalicular corresponding to the formation of the respiratory (breathing) of the bronchioles and alveolar, when formed alveolar ducts and alveoli.

primary rudiment of light detected in a 3-week embryo, a length of 3 mm.In the embryo 4 mm (gestational age - 1 week) formed the beginnings of giving further initiated the formation of the main bronchi.On the 5 th week of the beginnings continue to grow, giving rise to lobar bronchi.At 6-7 weeks of fetal development are the main bronchi and segmental bronchi beginnings and up to 8 weeks - subsegmental branching bronchi.

In parallel with the formation of the first bronchus for each lung differentiate pulmonary ar

tery.At 6-7 weeks there is arterial system of the pulmonary circulation.Pulmonary veins appear in the lung tissue bud and grow toward the heart.By the end of the 3rd month of fetal development the large bronchi are the structural elements of all three shells, their generators.At the same time begins the formation of the bronchial glands.On the 5-6 th month of fetal development there are small bronchi and respiratory bronchioles.Light at this time are well supplied with blood, the body, as in any other gland embryonic period is not so developed network of blood vessels.For 7 months of embryonic development, the structure of the respiratory tract is already capable of providing gas exchange processes.Formation of alveoli begins at the beginning of the 8 th month of fetal life.Since that time, a light fruit acquires a structure that has at birth.

Stopping or violation of embryonic development of the respiratory system are possible at various stages of its formation.This determines the diversity and nature of defects.So, stop development at the primary rudiment determines the absence of a bilateral (two-sided agenesis) light.Violation of the 4th week of the embryonic period causes a unilateral absence or hypoplasia of the lung.Such defects as polycystic, branching anomalies arise in later periods of fetal life.

Formation light goes on after birth.In the first 10 years of his life light is growing rapidly, the number of alveoli increases progressively, new bronchial ramifications.Malformations of the respiratory system in much of the cases are the basis for the formation of a child's recurrent (occurring with periodic exacerbations) and chronic lung disease.According malformations data available in the literature are diagnosed in 10-15% of people with chronic lung diseases.In the development of these defects lead role to the hereditary factors.It is believed that the contribution of these factors in the origin of defects exceeds 75-80%.Defects may be the result of gene mutations, chromosomal abnormalities and have multifactorial origins, t. E. To develop as a result of the influence of many factors.

Defects lungs clinically usually do not appear until the layering of any infection.Joining infection turns blemish carrier in a patient with chronic pneumonia.