Compliance curve of the lung given below. Curve A signifies which of the followings:
Compliance is defined as the change in volume for a unit change in pressure. It measures the distensibility or, stretchability of lung The total compliance of both lungs together in the normal adult human averages about 200 milliliters of air per centimeter of water transpulmonary pressure. The compliance of the combined lungthorax system is almost exactly one half that of the lungs alone-- 110 milliliters of volume per centimeter of water pressure. Types of compliance measurements: Static compliance: This is the measurement made without taking into account the effect of the different phases of respiration. Dynamic compliance: Compliance measurement during the difference phases of respiratory. So it's a measure of static compliance (lungs and chest wall stiffness) plus airway resistance = impedance of lung Specific compliance = Compliance/FRC Reduced compliance is caused by: Increased fibrous tissue in the lung (pulmonary fibrosis) Decreased surfactant or increased surface tension Presence of air (pneumothorax), excess fluid (pleural effusion), or blood (hemothorax) in the intrapleural space Alveolar edema, which prevents the inflation of some alveoli Atelectasis (collapse) Increased pulmonary venous pressure a lung becomes engorged with blood An increased compliance occurs in pulmonary emphysema normal aging lung In both instances, an alteration in the elastic tissue in the lung is probably responsible. Aging cause changes in the structure of lung collagen and elastin rather than changes in the amount or propoion of the two molecules. In emphysema, the alveolar septal tissue that normally opposes lung expansion are destroyed. Increased compliance also occurs during an asthma, but the reason is unclear.
Pulmonary fibrosis
Atelectasis
Emphysema
ARDS
Respiratory System