Lanier WI, Warner DO: Intracranial elastance versus intracranial compliance: Terminology should agree with that of other disciplines [letter]. Anesthesia, 3rd edition. Copyright by the American Society of Anesthesiologists, Inc. View Metrics. Citing articles via Web Of Science 3. Uptake of Halothane by the Human Body. Email alerts Article Activity Alert.
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Close Modal. Since the elastance in each of the lungs and the chest wall is approximately 5 cmH 2 O, the elastance of the respiratory system is approximately 10 cmH 2 O. Changes in the elastance and therefore the compliance of the chest wall are uncommon.
In contrast, the elastance of the lungs is affected by many respiratory diseases. Thus, variations in the elastance of the respiratory system are mainly due to alterations of the elastance of the lungs, which is governed by two main factors:. This accounts for approximately one fourth to one third of the elastic resistance of the lungs and holds the responsibility of generating the recoil forces necessary to increase the intra-alveolar pressure during expiration, which is a passive process.
This is responsible for the remaining two-thirds to three-fourths of the elastance of the lungs. Since the alveoli are globular structures, having a thin lining of fluid, which comes into contact with air, the net surface tension force acts inwards. When a whole lung is considered, the transmural pressure is the transpulmonary pressure intra-alveolar pressure — intra-pleural pressure. The contribution of elastic recoil and the surface tension on the total elastance can be demonstrated by pressure-volume curves, determined in vitro, of lungs which are either gas-filled or liquid filled.
The elastance of the gas-filled lungs can be assumed to have the same elastance as that, which is attached to the thoracic wall. Since, the surface tension forces are eliminated in the liquid-filled lungs as there is no air-liquid interface, the elastance becomes much lower approximately one-fourth compared to a normal lung as the elastance is entirely due to the elastin fibers.
Reduction in the surface tension would lead to a reduction in the trasnpulmonary pressure that is required to keep the alveoli expanded.
Thus, this decreases the power that needs to be generated by the muscles of inspiration and hence, the work of breathing. The surface tension in the lungs is reduced by a chemical agent, known as surfactant, secreted by the type II alveolar cells in the lungs. Details regarding the secretion of surfactant and the functions of surfactant will be described in a separate hub. Marine Biology.
Electrical Engineering. Compliance increase blood flow by converting elastic energy stored in arterial wall to movement energy. Blog Section Compliance and Elastance. Compliance:Dilation of the arteries, veins in response to mechanical load. Elastance: Resistance, stiffness of the arteries, veins in response to mechanical load Arteries have lower compliance and high elastance Veins heave high compliance and low elastance Compliance: reflects ability to change the shape of the structure when mechanical load applied.
Stored elastic energy in large and middle sized arteries windkessel During systole pressure elastance and volume compliance of the large arteries are increased. Energy Generated by Heart: -Movement energy blood flow -Pressure energy pressure of fluid -Elastic energy arterial wall During systole pressure energy converts to elastic energy and movement energy.
During diastole elastic energy of the arterial wall converts to movement energy.
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