Midterm Flashcards
Functions of the Conduction Zone
warm, humidify and filter air
Types of pnuemocyte
Type 1 - squamous epithelium
Type 2 - Produces surfactant
Atmospheric Pressure
Patm
-0 mmHg
Alveolar Pressure Palv
-must be negative (lower than Patm) during inspiration and higher during expiration
Transmural pressure
Palv - Pip
- the pressure difference across the alveolar wall
- as this increases alveoli size increases
Intrapleural Pressure Pip
- usually negative and keeps alveoli inflated
- decreasing this pulls on the alveoli increasing the volume
- change is generated by muscles
Compliance
delta V / delta P
with a lowered compliance you need to muscular work harder to breathe
Elasticity
Delta P / Delta V
-if lowered you need to work harder to exhale
What does surfactant do?
- inserts itself between water molecules and reduces surface tension
- increased lung V, surfactant spreads out and increases surface tension
Dynamic Compression
During forced expiration Pip becomes positive
- if Pip exceeds airway pressure than airways can narrow/collapse
- Pursed-lip breathing increases Palv to counter act this
What can cause Bronchiolar Smooth Muscle Constriction
- histamine
- PNS stimulation
- decreased PCO2
- expiration
What can cause Bronchiolar Smooth Muscle Relaxation
- epinephrine (Beta2 stim)
- increased PCO2
- inspiration
Inspiratory Reserve Volume
Top of TV to max inspiratory effort
Inspiratory Capacity
TV + IRV
Expiratory Reserve Volume
-low point of TV to the most they can expire
Residual volume
-gas that is left in the lungs that cannot be exhaled
Total Lung Capacity
IRV + TV + ERV + RV
Functional Residual Capacity
ERV + RV
FEV1
forced expiratory volume in 1 second
-should be 80% of FVC
Minute Ventilation
TV x f
Dead Space
volume of gas that fills conducting airways and doesn’t do gas exchange
Composition of Alveolar gas and pulmonary veins
100 mmHg of O2
40 mmHg of CO2
Composition of gas in pulmonary arteries and peripheral veins
40 mmHg of O2
46mmHg of CO2
Intrapulmonary Shunt
-perfusion w/o Ventilation