It's Not All Smooth Muscle: Non-Smooth-Muscle Elements in Control of Resistance to Airflow

Abstract

To achieve gas exchange, inspired air must pass through an intricate and dynamic tracheobronchial tree. The tree offers resistance to airflow, and increased resistance is the most important functional change in lung disease. Numerous mechanisms contribute to increased resistance by causing airway narrowing, closure, occlusion, and/or obliteration. Although airway smooth muscle (ASM) contraction and shortening are an important cause of increased resistance, non-ASM elements can also contribute. Nonmuscle elements can modify the amount of airway narrowing for any given level of ASM shortening and the amount of shortening for a given level of ASM activation. In this review, we outline the physiological basis for airflow resistance and describe how changes in the lung parenchyma, the airways, and their luminal contents can contribute to increased airflow resistance. A detailed understanding of the mechanisms and consequences of increased airway resistance is vital to our attempts to alleviate the enormous burden of suffering caused by obstructive lung diseases.

Mucociliary clearance: pathophysiological aspects

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Airway Smooth Muscle in Asthma Symptoms: Culprit but Maybe Innocent

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Dinámica y patología del barrido mucociliar como mecanismo defensivo del pulmón y alternativas farmacológicas de tratamiento

“…Una excesiva producción de moco impide su eliminación, aumenta la resistencia al flujo aéreo obstruyendo la vía aérea, y favorece la colonización bacteriana. Trastornos en su viscoelasticidad alteran las defensas contra las infecciones, inhibiendo la migración de neutrófilos, entre otros factores 27,28 .…”

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