Localization and Mechanisms of Airway Responses

Abstract

The air passages of the lung are not rigid tubes; they can reduce their caliber in response to chemicals, such as sulfur dioxide, drugs, such as histamine, and antigenic agents, such as ragweed pollen. The effects of these substances may be direct and local, or they may be reflexly mediated by the vagus nerve. The body's reactions can consist of smooth muscle constriction, mucosal edema with or without inflammatory-cell infiltration, increased secretions, altered clearance and changes in parenchymal elasticity, which depend on the nature of the agent, the dosage and the duration of exposure and subsequent response. These reactions appear . . .