PHYL2001 Lecture Notes - Lecture 9: Balloon Catheter, Lung Volumes, Spirometer
Document Summary
Ease with which lungs can be inflated distensibility. How much effort is required to distend/ inhale the lungs. With tidal inspiration- you require very little effort (tidal respiration the lungs are fairly compliant, and are little resistance to flow) If no negative pressure in the pleural cavity- work outwards: surface tension. Important usually happens at water-air interface: water molecules- attracted very tightly to each other- if in contact with air there is an increase in surface tension. Alveolar air liquid interface liquid within the cells. The water molecule- tend to pack tightly to each other. Inwardly directed force tends to reduce alveolar diameter. If calculate the pressure within the alveoli of different sizes will find that there is a greater pressure in smaller alveoli due to the different diameters. Since air flow goes down the pressure gradient- it would go down the pathway of least resistance.
