Chapter 27 Flashcards
What equilibrium generates a subatmospheric intrapleural pressure?
The balance between an outward elastic recoil of the lungs and the inward elastic recoil of the lungs.
What happens when the thorax volume is increased?
Inspiration of air
How is the volume of the thorax increased?
Contraction of the diaphragm and the intercostal muscles increases the volume of the thorax.
How does expiration occur?
Relaxation of the diaphragm and the intercostal muscles decreases the volume of the lung, producing expiration.
What does increasing the static compliance of the lungs do?
Makes it easier to inflate the lungs
What is responsible for the elastic recoil of the lungs?
Surface tension from the pulmonary surfactant
What is the pulmonary surfactant made of?
Mixture of lipids and apoproteins, mostly dipalmitoylphosphitidylcholine.
What does pulmonary surfactant do?
Reduce surface tension and increase compliance
What is airflow equal to?
Airflow = (Alveolar pressure - atmospheric pressure) / Airway resistance
Do alveolar pathways have high or low resistance to the conducting air pathways?
Low
What are 3 factors that increase airway resistance?
Vagal tone, histamine, and reduced lung volume
As respiratory frequency increases, what happens?
Dynamic compliance falls
During inspiration, does the transmural pressure dilate or constrict the pathways? How about during expiration?
Dilate during inspiration and constrict during expiration.
