As the branches of the bronchial tree get smaller, what component increases in concentration?

As the branches of the bronchial tree become progressively smaller, the concentration of smooth muscle increases significantly. This is crucial because smooth muscle plays a vital role in regulating airway diameter through contraction and relaxation, which directly affects airflow resistance and the distribution of air within the lungs.

In the larger bronchi, there is more cartilage present, providing structural support to keep the airways open. However, as bronchi narrow into bronchioles, the amount of cartilage decreases, and the surrounding smooth muscle becomes more prominent. This allows for better control over the diameter of the airways, particularly important during processes such as bronchoconstriction and bronchodilation, which can be vital in response to various physiological needs or pathological conditions.

Elastic fibers also play a role in the bronchial tree, aiding in the recoil of airways after inhalation, but the increase in smooth muscle is particularly crucial for dynamic control of airflow. The prominence of epithelial tissue remains relatively consistent; however, the changes in smooth muscle content are key to understanding the functional adaptations throughout the bronchial tree.