Lung bronchus in case of asthma, cross-section
Cross-section through a lung bronchus of a lung that's suffering from bronchitis. The wall layers are identifiable, from outside to inside: Cartilagenous layer, muscular layer, and respiratory epithelium with microvilli. The bronchus is severly constricted due to a massive mucosal swelling (innermost layer), e.g. due to asthma bronchiale with bronchospasm. The alveoles are shown in the background.
