what is the function of bronchioles in respiratory system

The bronchioles are part of the tracheobronchial tree, which is where air passes to your lungs and exchanges gases (oxygen and carbon dioxide) . The bronchioles are one of the smallest airways in the respiratory tract, and their function is to deliver air to a diffuse network of around 300 million alveoli in the lungs. The bronchioles carry oxygen-rich air into the lungs and carry carbon dioxide-rich air out of the lungs, thereby facilitating gas exchange. The bronchioles also help moisturize the air you breathe and screen out foreign particles. The airways are lined with cells that create mucus, which keeps your airways moist and traps bacteria, viruses, fungi, and other particles to protect your lungs and prevent infection. The bronchioles are lined with cilia, tiny hairlike structures that help move mucus (phlegm) and particles out of your lungs. When you cough or swallow, the particles trapped in the mucus move out of your body or into your digestive tract, where your body can dispose of them.