Bronchioloide
Bronchioloides are small, thin-walled airways that branch off from the terminal bronchioles in the lungs. They are part of the respiratory system and play a crucial role in gas exchange. Unlike the larger bronchi and bronchioles, bronchioloides are not lined with ciliated epithelium, which is responsible for moving mucus and foreign particles out of the lungs. Instead, they are lined with simple squamous epithelium, which facilitates the diffusion of gases between the alveoli and the bloodstream. The walls of bronchioloides are composed of smooth muscle, elastic fibers, and collagen, which help maintain their patency and support their structure. These airways are particularly important in the early stages of lung development and in certain respiratory conditions, such as chronic obstructive pulmonary disease (COPD), where they may become dilated and contribute to airflow obstruction.