Use LEFT and RIGHT arrow keys to navigate between flashcards;
Use UP and DOWN arrow keys to flip the card;
H to show hint;
A reads text to speech;
31 Cards in this Set
- Front
- Back
What is the pressure reference point in pulmonary medicine?
|
ambient air pressure
e.g.: Patm = 740 = 0 |
|
What does it mean to have "negative pressure in the lungs"
|
pressure is less than ambient air pressure
|
|
general equation for distending pressure
|
distending pressure = pressure inside - pressure outside
|
|
lung distending pressure, aka:
|
transpulmonary pressure (PTP)
|
|
PTP =
|
PTP = Palveolar - Pip
|
|
Intrapleural pressure must be _____ to keep the lungs distended
|
Intrapleural pressure must be SUB-ATMOSPHERIC to keep the lungs distended
|
|
What must be true for distending pressue to be positive?
How does lung achieve this? |
Pressure inside > pressure outside
by keeping Pip < Patm |
|
Just before inspiration begins, Palveolar =
|
Just before inspiration begins,
P(alveolar) = Patm |
|
Lung volume just prior to inspiration =
|
FRC
|
|
7 steps of inspiration
|
inspiratory muscles contract
chest wall expands and diaphragm lowers intrapelural pressue (Pip) becomes more negative than -5 cm H2O tranplumonary pressure increases (becomes more positive than +5 cm H2O) lungs expand alveolar pressure decreases below Patm air flows into lungs |
|
Physical law describing flow of air into lungs during inspiration
|
Ohm's Law:
Flow = Driving force * conductance = driving force/resistance = (Patm - P(alveolar))/airway resistance |
|
What must happen wrt pressures to cause expiration?
|
P(alveolar) must rise above Patm
|
|
7 steps of expiration
|
inspiratory muscles relax
chest wall moves inward/diaphragm upward Pip becomes less negative PTP decreases lungs decrease in size Palveolar increases air flows out of the lungs |
|
compliance =
lung compliance = |
compliance = change in volume/change in distending pressure
lung compliance = change in vol./change in PTP = slop of line in lung vol. vs. PTP graph |
|
restrictive pulmonary disease is characterized by abnormally...
|
restritive pulmonary disease is characterized by abnormally LOW LUNG COMPLIANCE
|
|
Lungs in restrictive pulmonary disease require an abnormally large ______ to inflate
|
distending pressure
|
|
Which pressure must be greater than normal to inflate lungs in restrictive disease?
|
distending pressure, aka: PTP
|
|
TO achive normal FRC in restrictive disease, which pressure must be LOWER than normal?
|
Pip
|
|
How does the body make Pip lower than normal in restrictive disease?
|
powerful contraction of inspiratory muscles
|
|
3 clinical examples of restrictive disease
|
pulmonary fibrosis (fibrous replaces elastic tissue)
pulmonary edema (tissue water-logged, stiff) infant respiratory distress syndrome (inadequate sufactant, high surface tension in fluid lining alveoli, stiff alveoli) |
|
Clinical values characterizing restrictive disease
|
FEV1/FVC is NOT REDUCED
& TLC decreased a lot residual volume decreased some ergo, FVC is decreased |
|
Obstructive pulmonary disease is characterized by abnormally...
|
obstructive disease is characterized by abnormally HIGH AIRWAY RESISTANCE
|
|
Is there a problem holidng lungs at FRC in obstructive disease?
|
No
|
|
which cells in alveoli does surfactant cover?
|
all of them - thin walls, too!
|
|
what leads to obstruction, restriction AND alveolar diffusion limitation?
|
pulmonary edema
|
|
equation for oxygen consumption
|
??
|
|
pulmonary vascular resistance =
|
(pulm artery pressure - LA pressure)/CO
|
|
The air in Lansing has ____ PO2 in comparison with the air on a mountain top.
|
The air in Lansing has a HIGHER PO2 in comparison with the air on a mountain top.
|
|
normal PaO2
|
100 mmHg
|
|
normal PaCO2
|
40 mmHg
|
|
normal [HCO3-]
|
24 mM
|