PSIO 532 Study Guide - Midterm Guide: Bronchiole, Intrapleural Pressure, Transpulmonary Pressure
PSL – Respiratory Physiology
Functional Residual Capacity
This graph shows the relationship between airway resistance
and lung volume. As the lung volume decreases below
normal, airway resistance is increased. This is because the structure of the lung is such that
inflation of alveoli results in the structural support of the small airways. Note the close
relationship of the bronchiole in the inset picture to the alveoli surrounding it.
❖ We see a bronchiole (the hole), and it is surrounded by alveoli → air enters the alveoli,
the alveoli expands, and the alveoli tends to cause radial traction on the bronchiole;
alveoli dilates the bronchiole due to the expansion of the alveoli → decrease resistance
❖ The relationship between lung volume and resistance is seen on the left
❖ Recognize that we are typically working at FRC; in the example shown, we are at blue
circle
❖ However, if we have variations in lung volume: if we reduce our lung volume, we will
get less radial traction, and due to this we will get reduction in the radius and increase
in airway resistance
❖ If you increase lung volume, we will get increase in pulling of the small bronchiole →
this will increase the radius, which will decrease the resistance
❖ Individuals with COPD, there is a change in relationship between lung volume and
airway resistance → for a given lung volume, you have a greater airway resistance for
individuals with COPD
find more resources at oneclass.com
find more resources at oneclass.com
Document Summary
This graph shows the relationship between airway resistance and lung volume. As the lung volume decreases below normal, airway resistance is increased. This is because the structure of the lung is such that inflation of alveoli results in the structural support of the small airways. Note the close relationship of the bronchiole in the inset picture to the alveoli surrounding it. The relationship between lung volume and resistance is seen on the left. Recognize that we are typically working at frc; in the example shown, we are at blue circle. However, if we have variations in lung volume: if we reduce our lung volume, we will get less radial traction, and due to this we will get reduction in the radius and increase in airway resistance. If you increase lung volume, we will get increase in pulling of the small bronchiole this will increase the radius, which will decrease the resistance.
