Lecture 17: The Work of Breathing Flashcards
The pressure of a gas is inversely proportional to its
volume
Decreased volume results in
increased pressure
Increased volume results in
decreased pressure
Pressure is proportional to the concentration because
of collisions of molecules with each other and with the container
Less collisions means
less pressure
More collisions means
more pressure
What drives the movement of gases?
a pressure gradient
Gas will more from _____ pressure to ________ pressure
high
low
Right before a breath, the pressure outside the body is _______ ______ the pressure inside the body so the air
equal to
does not flow
Describe the pressure gradient created when you inhale including how this affects the volume, the pressure and the flow of air
as you inhale
- volume increases
- pressure decreases
- air from the outside rushes into your lungs
Describe the pressure gradient created when you exhale including how this affects the volume, the pressure and the flow of air
as you exhale
- volume decreases
- pressure increases
- air from your lungs rushes outwards
What are the two opposing forces that must be overcome to take a breath?
- stiffness of the lungs
- resistance of the airways to the lungs
Describe why the stiffness of the lungs must be overcome?
The lungs don’t want to inflate naturally so there is resistance to stretching and accomodating the air
What two things determine the stiffness of the lungs?
their compliance and the surface tension which holds the lungs in place
What is compliance?
The ability to expand and accomodate an increased volume