Respiration 2 Flashcards
What is compliance?
A measure of elasticity
What is the equation for compliance?
C = DeltaV/DeltaP
How does low compliance affect respiration?
Stiffer muscles require more energy to expand so more energy is required to inspire.
Volume change is smaller
How does high compliance affect respiration?
There is a lack of elastic recoil
Tissues around the lungs may be broken down so smaller airways become easier to collapse.
More difficulty expiring
What are the 2 major components of elastic recoil?
Surface tension
Elastic tissues
How is elastic recoil created due to surface tension?
Surface tension is generated at air-fluid interface
Difference in forces of water molecules but no up pull so vector is downwards ->
Molecules remaining at the surface develop opposing forces
What is Laplace’s equation? What does it explain?
P = 2T/r (pressure, tension, radius)
The balance between pressure exerted by the gas and the surface tension in a gas bubble/
Why will air flow from smaller alveoli to larger alveoli?
Laplace’s law states twice as much pressure us needed to keep the smaller sacs inflated so the smaller one will empty into the larger one
What specialisation allows small alveoli sacs to overcome collapsing?
Surfactant
- Reduces surface tension
How does surfactant reduce surface tension?
Decreases the density of the water molecules because their hydrophobic tails pull them upward, reducing the downwards vector
What do type 2 pneumocytes produce?
Surfactant
How does a spirometer work?
Pen goes up on expiration and down on inspiration
What are the 2 types of dead space?
Anatomical
Physiological
Describe anatomical dead space
Volume of conducting airways
(trachea, bronchi and bronchioles)
150mls at rest
Describe physiological dead space
Volume of lungs not participating in gas exchange
Conducting zone and non functional areas of the respiratory zone
