Which factors are the three main influencers of resistance in the respiratory system?

The three main influencers of resistance in the respiratory system focus on how obstructions and changes within the airways can affect airflow. Bronchiolar diameter is particularly significant because the narrower the airways, the greater the resistance to airflow, making it more challenging for air to be drawn into or expelled from the lungs. Changes in bronchiolar diameter can occur due to various factors, including smooth muscle contraction or relaxation, which can be influenced by factors like inflammation, allergens, or irritants.

Pulmonary compliance refers to the ability of the lung tissue to stretch and expand. If the lungs are stiff or less compliant due to conditions such as pulmonary fibrosis or edema, it can limit lung expansion and thus influence airflow resistance indirectly, as the lungs may not adequately fill with air.

Surface tension, primarily at the air-liquid interfaces within the alveoli, plays a crucial role in maintaining alveolar stability and affects the ease with which the lungs can expand. Surfactant decreases surface tension, helping to maintain alveolar structure and preventing collapse, thus facilitating easier air movement.

Understanding how these factors interact helps explain the mechanics of ventilation and how diseases can influence respiratory resistance, making option B the right choice.