Final answer:
Elastic recoil is the lung's tendency to return to its original shape after expansion, while compliance is a measurement of the lung's elasticity. In asthma, elastic recoil decreases while compliance may remain normal, leading to airway obstruction and difficulty in exhalation. Expiratory Reserve Volume is often reduced in asthma due to these obstructions.
Step-by-step explanation:
Elastic Recoil and Compliance in Asthma
The elastic recoil is a property of the lung that influences it to return to its original shape after being stretched, much like a rubber band snapping back after being extended. This property drives the lung tissue inward during exhalation. In the case of asthma, which is an obstructive pulmonary disease, inflammation triggered by environmental factors leads to airway obstruction. This obstruction can be due to edema, smooth muscle spasms in the bronchioles, increased mucus secretion, or damage to the epithelia of the airways. These factors lead to a decrease in the elastic recoil because the airways cannot constrict and expel air efficiently.
Compliance refers to the measurement of the elasticity or 'stretchiness' of the lung. Pulmonary diseases can affect lung compliance, which in turn influences the ease of breathing. In asthma, compliance is often normal, but the ability to exhale effectively is compromised due to increased resistance in the airways. Therefore, patients may have a normal lung volume but face difficulty in expelling air, leading to symptoms such as wheezing and shortness of breath.
Expiratory Reserve Volume (ERV) is the amount of additional air that can be forcibly exhaled after a normal exhalation. In diseases like asthma, ERV may be reduced due to the difficulty in expelling air caused by obstructed airways. Thus, people with asthma have a tendency to breathe at a higher lung volume to compensate for the lack of efficient airway clearance, resulting in larger volumes of air being trapped after exhalation.