Physiology - overview of respiratory system Flashcards
does gas exchange occur through type I or II alveolar cells
type I
Type II alveolar cells function
secrete surfactant, reabsorb Na ions and water
compliance definition
change in lung volume per change in transpulmonary pressure
diseases associated with increased compliance
emphysema
hyperinflation of lungs
old age
diseases associated with decreased compliance
pneumonia
pulmonary fibrosis
surfactant effect on surface tension and compliance
reduce surface tension
increase compliance
surfactant effect on hydrogen bonds in water molecules
reduces H bonds between water molecules
RDS
respiratory distress syndrome
- absent/insufficient surfactant in premature babies causes RDS due to collapse of primitive alveoli
Tidal volume
volume of gas inspired or expired in an unforced respiratory cycle
residual volume
volume of gas in lungs after maximum expiration
functional residual capacity
amount of gas in lungs after normal tidal expiration
air in anatomical dead space has inc/dec CO2 and O2 concentration
increased CO2 concentration
decreased O2 concentration
parasympathetic - broncho construction/dilation
bronchoconstriction
sympathetic - broncho construction/dilation
bronchodilation
- decreased resistance
- increase air flow
forces promoting alveolar collapse
elasticity
alveolar surface tension
- attraction between water molecules at liquid air surface
forces keeping alveoli open
transmural pressure gradient
pulmonary surfactant
alveolar interdependence
law of laplace
pressure is proportional to surface tension and inversely proportional to alveolar radius
boyle’s law
pressure is inversely proportional to volume
henry’s law
concentration of gas dissolved in a liquid is proportional to partial pressure of gas
dalton’s law
pressire exerted by a gas mixture equals the sum of pressures that would be exerted by each gas alone
2 factors in linkage of lungs to thorax
intrapleural fluid cohesiveness
- water molecules in intrapleural fluid are attracted together, resist pulling apart
negative intrapleural pressure
- lungs expand out, chest in
