Emphysema

Pathogenesis. Many theories of pathogenesis of emphysema explain only a few cases of emphysema or on factors playing, perhaps a supporting role.
Extrapulmonary theory put forward in the first place changes chest and spine.
Theory of reducing the elasticity of the lung is congenital or as a result of inflammation is not confirmed as next of old studies and modern measuring the elasticity of the lung tissue.
Related to the previous theory pererastala light on voltage - emphysema musicians and glass-blowers is also refuted by modern observations.
The theory of the initial changes in vessels of the small circle of blood circulation (P. Beresnevich) or bronchial arteries [Cudkowicz and Armstrong (L. Cudkowitz, J. Armstrong)] in some cases only explains atrophic processes in the lung tissue.
The theory of nervous origin of emphysema - increasing inspiratory pulse (I. L. Biryukov), changing the reflex of Hering - Breuer (bpts Kushelev) - also do not explain the increase in residual air. More likely part of the nervous system in the implementation of bronchospasm.
The so-called obstructive theory is now widely accepted and most justified on objective methods. According to this theory, the narrowing of the bronchial tubes can be caused by a spasm of the bronchial muscles (not always detected posthumously), swelling of mucous membrane, viscous sputum, pressing inflamed bronchial tubes or scar peribronchial cloth, which flabby bronchial wall is subjected to compression of the surrounding lung tissue on the exhale.
According to the law Poiseuille flow resistance to the flow of air increases inversely proportional to the fourth power of the radius. Reduction of bronchi doubles the resistance to the flow of air in 16 times. To promote air requires a greater effort, the greater the pressure drop. In these cases, to ensure that (despite the increase resistance) proper ventilation exhale (usually passive) becomes active. As the narrowing of the bronchi increases the increased intrathoracic pressure; when the alveoli, the surrounding of the small bronchi constrict bronchus, creating the so-called valve mechanism (C. E. Votchal). Due to the irregular narrowing of the small bronchi air from the alveoli, bronchus which narrowed, starts to pass through the so-called pores Kona to neighbouring alveoli with less narrow bronchus; expands and then break millionares partitions. Due to reduced clearance bronchi as the last exhale is limited, which leads to an increase of the residual volume of air.
Reflex (compensatory) gradually created position of the chest, close to the maximum breath, which leads not only to the useful bronchi, but also harmful to stretch of the alveoli. The pressure in the alveoli on the exhale, squeezing the capillaries that impairs blood flow and increases the atrophy.
The leading mechanism in the narrowing of the bronchi is a spasm of smooth muscles. It may be called infectious-allergic factor (I. A. Chernogorov), Central nervous way: through the vagus nerve, such as contusions (bpts Kushelev), and also due to high sensitivity receptors in the bronchi. The last mechanism is proved by lowering the threshold to aerosols acetylcholine [tiffno (Century Tiffeneau)]. In most cases, there comes a narrowing of the small bronchi. However, the described cases [Duke (N. Herzog) and others], which emphysema developed due to sagging pars merabranacea trachea, and large bronchi. Bronchoscopy in these cases, we could see that the back wall of the trachea during the forced expiratory were showing through, into the lumen of the trachea, almost completely closing. This mechanism is often attached to the violation of patency of the small bronchi.
Obstructive theory explains the emergence not only of emphysema, but a sharp blow-UPS of the lungs during an attack of asthma in capillary bronchitis (influenza, action, S, drowning).